nightly-2016-10-11

mapping.rs

@@ -89,3 +89,77 @@
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src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/buffered.rs

@@ -0,0 +1,1146 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/memchr.rs

@@ -0,0 +1,410 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = if end_align >= len { 0 } else { len - end_align };
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment_reversed() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/mod.rs

@@ -0,0 +1,1943 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/117cbb879e6ef498ea04e08bd80688bf2fc4a183/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/buffered.rs

@@ -0,0 +1,1146 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// at the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/cursor.rs

@@ -0,0 +1,594 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use core::convert::TryInto;
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos: usize = self.position().try_into().map_err(|_| {
+            Error::new(ErrorKind::InvalidInput,
+                       "cursor position exceeds maximum possible vector length")
+        })?;
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let len = self.inner.len();
+        if len < pos {
+            // use `resize` so that the zero filling is as efficient as possible
+            self.inner.resize(pos, 0);
+        }
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position((pos + buf.len()) as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    #[cfg(target_pointer_width = "32")]
+    fn vec_seek_and_write_past_usize_max() {
+        let mut c = Cursor::new(Vec::new());
+        c.set_position(<usize>::max_value() as u64 + 1);
+        assert!(c.write_all(&[1, 2, 3]).is_err());
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/memchr.rs

@@ -0,0 +1,143 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+#[inline]
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    ::sys::memchr::memchr(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+#[inline]
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    ::sys::memchr::memrchr(needle, haystack)
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/mod.rs

@@ -0,0 +1,1979 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` or EOF is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 if buf.len() != 0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "23755")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[test]
+    fn chain_zero_length_read_is_not_eof() {
+        let a = b"A";
+        let b = b"B";
+        let mut s = String::new();
+        let mut chain = (&a[..]).chain(&b[..]);
+        chain.read(&mut []).unwrap();
+        chain.read_to_string(&mut s).unwrap();
+        assert_eq!("AB", s);
+    }
+
+    #[bench]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/1f9036872d7ea8bee91f8588e3c4a613c58c76cb/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/buffered.rs

@@ -0,0 +1,1145 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// at the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/memchr.rs

@@ -0,0 +1,410 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = if end_align >= len { 0 } else { len - end_align };
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment_reversed() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/mod.rs

@@ -0,0 +1,1981 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 if buf.len() != 0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "0")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[test]
+    fn chain_zero_length_read_is_not_eof() {
+        let a = b"A";
+        let b = b"B";
+        let mut s = String::new();
+        let mut chain = (&a[..]).chain(&b[..]);
+        chain.read(&mut []).unwrap();
+        chain.read_to_string(&mut s).unwrap();
+        assert_eq!("AB", s);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/26f9949bf678abc1fae595e3f6eb59a5bf8a7564/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/buffered.rs

@@ -0,0 +1,1146 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// at the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 exbibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/cursor.rs

@@ -0,0 +1,594 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use core::convert::TryInto;
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos: usize = self.position().try_into().map_err(|_| {
+            Error::new(ErrorKind::InvalidInput,
+                       "cursor position exceeds maximum possible vector length")
+        })?;
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let len = self.inner.len();
+        if len < pos {
+            // use `resize` so that the zero filling is as efficient as possible
+            self.inner.resize(pos, 0);
+        }
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position((pos + buf.len()) as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    #[cfg(target_pointer_width = "32")]
+    fn vec_seek_and_write_past_usize_max() {
+        let mut c = Cursor::new(Vec::new());
+        c.set_position(<usize>::max_value() as u64 + 1);
+        assert!(c.write_all(&[1, 2, 3]).is_err());
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/memchr.rs

@@ -0,0 +1,143 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+#[inline]
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    ::sys::memchr::memchr(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+#[inline]
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    ::sys::memchr::memrchr(needle, haystack)
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/mod.rs

@@ -0,0 +1,1979 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` or EOF is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 if buf.len() != 0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "23755")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[test]
+    fn chain_zero_length_read_is_not_eof() {
+        let a = b"A";
+        let b = b"B";
+        let mut s = String::new();
+        let mut chain = (&a[..]).chain(&b[..]);
+        chain.read(&mut []).unwrap();
+        chain.read_to_string(&mut s).unwrap();
+        assert_eq!("AB", s);
+    }
+
+    #[bench]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/8d06332a27b020f5252238946fa9dccc3843d52a/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/8d06332a27b020f5252238946fa9dccc3843d52a/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/buffered.rs

@@ -0,0 +1,1148 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/cursor.rs

@@ -0,0 +1,585 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+    use vec::Vec;
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/error.rs

@@ -0,0 +1,415 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use convert::Into;
+use error;
+use fmt;
+use marker::{Send, Sync};
+use option::Option::{self, Some, None};
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// `ErrorKind`.
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// Any I/O error not part of this list.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use prelude::v1::*;
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/impls.rs

@@ -0,0 +1,289 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+use string::String;
+use vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use vec::Vec;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/memchr.rs

@@ -0,0 +1,388 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = len - cmp::min(usize_bytes - end_align, len);
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/mod.rs

@@ -0,0 +1,1927 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try!.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use iter::{Iterator};
+use marker::Sized;
+use ops::{Drop, FnOnce};
+use option::Option::{self, Some, None};
+use result::Result::{Ok, Err};
+use result;
+use string::String;
+use str;
+use vec::Vec;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args!.html
+    /// [write]: ../macro.write!.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with `SeekFrom::Start`.
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/92400cf8dcf411ce7e70ab2960639977d46d5b01/util.rs

@@ -0,0 +1,217 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/buffered.rs

@@ -0,0 +1,1146 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/error.rs

@@ -0,0 +1,561 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// Any I/O error not part of this list.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/memchr.rs

@@ -0,0 +1,388 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = len - cmp::min(usize_bytes - end_align, len);
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/mod.rs

@@ -0,0 +1,1943 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/9a2c8783d91624261317316f996d8d2d09b7b6a4/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/buffered.rs

@@ -0,0 +1,1146 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// at the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/memchr.rs

@@ -0,0 +1,230 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+#[allow(dead_code)]
+pub mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = if end_align >= len { 0 } else { len - end_align };
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment_reversed() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+        }
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/mod.rs

@@ -0,0 +1,1979 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` or EOF is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 if buf.len() != 0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "0")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[test]
+    fn chain_zero_length_read_is_not_eof() {
+        let a = b"A";
+        let b = b"B";
+        let mut s = String::new();
+        let mut chain = (&a[..]).chain(&b[..]);
+        chain.read(&mut []).unwrap();
+        chain.read_to_string(&mut s).unwrap();
+        assert_eq!("AB", s);
+    }
+
+    #[bench]
+    #[cfg_attr(target_os = "emscripten", ignore)]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/d311079a6f70577d02f35bb80d27eef7e2b18a4a/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/buffered.rs

@@ -0,0 +1,1145 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/memchr.rs

@@ -0,0 +1,410 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = if end_align >= len { 0 } else { len - end_align };
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment_reversed() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/mod.rs

@@ -0,0 +1,1970 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "0")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/d6aa4e828c3dc3b7c417197990741b024f8c4ca3/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/buffered.rs

@@ -0,0 +1,1145 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// at the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            Write::write(&mut self.buf, buf)
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/error.rs

@@ -0,0 +1,562 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error;
+use fmt;
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// A marker variant that tells the compiler that users of this enum cannot
+    /// match it exhaustively.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/impls.rs

@@ -0,0 +1,285 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/memchr.rs

@@ -0,0 +1,410 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = if end_align >= len { 0 } else { len - end_align };
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment_reversed() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn each_alignment() {
+        let mut data = [1u8; 64];
+        let needle = 2;
+        let pos = 40;
+        data[pos] = needle;
+        for start in 0..16 {
+            assert_eq!(Some(pos - start), memchr(needle, &data[start..]));
+        }
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/mod.rs

@@ -0,0 +1,1970 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use result;
+use str;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+
+    /// Consumes the `Take`, returning the wrapped reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io_take_into_inner)]
+    ///
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut file = try!(File::open("foo.txt"));
+    ///
+    /// let mut buffer = [0; 5];
+    /// let mut handle = file.take(5);
+    /// try!(handle.read(&mut buffer));
+    ///
+    /// let file = handle.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io_take_into_inner", issue = "0")]
+    pub fn into_inner(self) -> T {
+        self.inner
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/e107c8b84969fbe52cae7c9fd61858fddc6e016b/util.rs

@@ -0,0 +1,215 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/buffered.rs

@@ -0,0 +1,1148 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/cursor.rs

@@ -0,0 +1,585 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+    use vec::Vec;
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/error.rs

@@ -0,0 +1,566 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use convert::Into;
+use error;
+use fmt;
+use marker::{Send, Sync};
+use option::Option::{self, Some, None};
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// Any I/O error not part of this list.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use prelude::v1::*;
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/impls.rs

@@ -0,0 +1,289 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+use string::String;
+use vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use vec::Vec;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/memchr.rs

@@ -0,0 +1,388 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = len - cmp::min(usize_bytes - end_align, len);
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/mod.rs

@@ -0,0 +1,1951 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use iter::{Iterator};
+use marker::Sized;
+use ops::{Drop, FnOnce};
+use option::Option::{self, Some, None};
+use result::Result::{Ok, Err};
+use result;
+use string::String;
+use str;
+use vec::Vec;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args.html
+    /// [write]: ../macro.write.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/e6cc4c5d13f8819c72568f9675e84c1d17368c67/util.rs

@@ -0,0 +1,217 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/buffered.rs

@@ -0,0 +1,1118 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = try!(self.fill_buf());
+            try!(rem.read(buf))
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = try!(self.inner.read(&mut self.buf));
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = try!(self.inner.seek(SeekFrom::Current(offset)));
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                try!(self.inner.seek(SeekFrom::Current(-remainder)));
+                self.pos = self.cap; // empty the buffer
+                result = try!(self.inner.seek(SeekFrom::Current(n)));
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = try!(self.inner.seek(pos));
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            try!(self.flush_buf());
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = try!(self.inner.write(&buf[..i + 1]));
+                if n != i + 1 { return Ok(n) }
+                try!(self.inner.flush());
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().err().unwrap();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/cursor.rs

@@ -0,0 +1,583 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = try!(Read::read(&mut try!(self.fill_buf()), buf));
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = try!((&mut self.inner[(pos as usize)..]).write(data));
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = try!((&mut self.inner[(pos as usize)..]).write(buf));
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+    use vec::Vec;
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/error.rs

@@ -0,0 +1,400 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use convert::Into;
+use error;
+use fmt;
+use marker::{Send, Sync};
+use option::Option::{self, Some, None};
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// `ErrorKind`.
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    #[allow(missing_docs)]
+    #[unstable(feature = "read_exact_old", reason = "recently added",
+               issue = "0")]
+    #[rustc_deprecated(since = "1.6.0", reason = "renamed to UnexpectedEof")]
+    UnexpectedEOF,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// Any I/O error not part of this list.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    #[allow(deprecated)] // remove with UnexpectedEOF
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEOF => "unexpected end of file",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use prelude::v1::*;
+    use super::{Error, ErrorKind};
+    use error;
+    use error::Error as error_Error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/impls.rs

@@ -0,0 +1,289 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+use string::String;
+use vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if try!(self.write(data)) == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use vec::Vec;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/memchr.rs

@@ -0,0 +1,388 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = len - cmp::min(usize_bytes - end_align, len);
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all plattforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/mod.rs

@@ -0,0 +1,2005 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     let line = try!(line);
+//!     println!("{}", line);
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions]: #functions
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try!.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use iter::{Iterator};
+use marker::Sized;
+use ops::{Drop, FnOnce};
+use option::Option::{self, Some, None};
+use result::Result::{Ok, Err};
+use result;
+use string::String;
+use str;
+use vec::Vec;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 64 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+
+    /// Creates a reader adaptor which will write all read data into the given
+    /// output stream.
+    ///
+    /// Whenever the returned `Read` instance is read it will write the read
+    /// data to `out`. The current semantics of this implementation imply that
+    /// a `write` error will not report how much data was initially read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer1 = Vec::with_capacity(10);
+    /// let mut buffer2 = Vec::with_capacity(10);
+    ///
+    /// // write the output to buffer1 as we read
+    /// let mut handle = f.tee(&mut buffer1);
+    ///
+    /// try!(handle.read(&mut buffer2));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    #[rustc_deprecated(reason = "error handling semantics unclear and \
+                                 don't seem to have an ergonomic resolution",
+                       since = "1.6.0")]
+    #[allow(deprecated)]
+    fn tee<W: Write>(self, out: W) -> Tee<Self, W> where Self: Sized {
+        Tee { reader: self, writer: out }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args!.html
+    /// [write]: ../macro.write!.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Creates a new writer which will write all data to both this writer and
+    /// another writer.
+    ///
+    /// All data written to the returned writer will both be written to `self`
+    /// as well as `other`. Note that the error semantics of the current
+    /// implementation do not precisely track where errors happen. For example
+    /// an error on the second call to `write` will not report that the first
+    /// call to `write` succeeded.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer1 = try!(File::create("foo.txt"));
+    /// let mut buffer2 = Vec::new();
+    ///
+    /// // write the output to buffer1 as we read
+    /// let mut handle = buffer1.broadcast(&mut buffer2);
+    ///
+    /// try!(handle.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    #[rustc_deprecated(reason = "error handling semantics unclear and \
+                                 don't seem to have an ergonomic resolution",
+                       since = "1.6.0")]
+    #[allow(deprecated)]
+    fn broadcast<W: Write>(self, other: W) -> Broadcast<Self, W>
+        where Self: Sized
+    {
+        Broadcast { first: self, second: other }
+    }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with `SeekFrom::Start`.
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buff
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// A `Write` adaptor which will write data to multiple locations.
+///
+/// This struct is generally created by calling [`broadcast()`][broadcast] on a
+/// writer. Please see the documentation of `broadcast()` for more details.
+///
+/// [broadcast]: trait.Write.html#method.broadcast
+#[unstable(feature = "io", reason = "awaiting stability of Write::broadcast",
+           issue = "27802")]
+#[rustc_deprecated(reason = "error handling semantics unclear and \
+                             don't seem to have an ergonomic resolution",
+                   since = "1.6.0")]
+pub struct Broadcast<T, U> {
+    first: T,
+    second: U,
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Write::broadcast",
+           issue = "27802")]
+#[rustc_deprecated(reason = "error handling semantics unclear and \
+                             don't seem to have an ergonomic resolution",
+                   since = "1.6.0")]
+#[allow(deprecated)]
+impl<T: Write, U: Write> Write for Broadcast<T, U> {
+    fn write(&mut self, data: &[u8]) -> Result<usize> {
+        let n = try!(self.first.write(data));
+        // FIXME: what if the write fails? (we wrote something)
+        try!(self.second.write_all(&data[..n]));
+        Ok(n)
+    }
+
+    fn flush(&mut self) -> Result<()> {
+        self.first.flush().and(self.second.flush())
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match try!(self.first.read(buf)) {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = try!(self.inner.read(&mut buf[..max]));
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        let buf = try!(self.inner.fill_buf());
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+/// An adaptor which will emit all read data to a specified writer as well.
+///
+/// This struct is generally created by calling [`tee()`][tee] on a reader.
+/// Please see the documentation of `tee()` for more details.
+///
+/// [tee]: trait.Read.html#method.tee
+#[unstable(feature = "io", reason = "awaiting stability of Read::tee",
+           issue = "27802")]
+#[rustc_deprecated(reason = "error handling semantics unclear and \
+                             don't seem to have an ergonomic resolution",
+                   since = "1.6.0")]
+pub struct Tee<R, W> {
+    reader: R,
+    writer: W,
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::tee",
+           issue = "27802")]
+#[rustc_deprecated(reason = "error handling semantics unclear and \
+                             don't seem to have an ergonomic resolution",
+                   since = "1.6.0")]
+#[allow(deprecated)]
+impl<R: Read, W: Write> Read for Tee<R, W> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        let n = try!(self.reader.read(buf));
+        // FIXME: what if the write fails? (we read something)
+        try!(self.writer.write_all(&buf[..n]));
+        Ok(n)
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        let mut buf = [0];
+        match self.inner.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(e) => Some(Err(e)),
+        }
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let mut buf = [0];
+        let first_byte = match self.inner.read(&mut buf) {
+            Ok(0) => return None,
+            Ok(..) => buf[0],
+            Err(e) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.char_at(0)),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/f1e191c0b959111aef19f3aa06b7f1743419470c/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/f1e191c0b959111aef19f3aa06b7f1743419470c/util.rs

@@ -0,0 +1,227 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        try!(writer.write_all(&buf[..len]));
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io;
+/// use std::io::Read;
+///
+/// # fn foo() -> io::Result<String> {
+/// let mut buffer = String::new();
+/// try!(io::empty().read_to_string(&mut buffer));
+/// # Ok(buffer)
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+
+    #[test]
+    #[allow(deprecated)]
+    fn tee() {
+        let mut buf = [0; 10];
+        {
+            let mut ptr: &mut [u8] = &mut buf;
+            assert_eq!(repeat(4).tee(&mut ptr).take(5).read(&mut [0; 10]).unwrap(), 5);
+        }
+        assert_eq!(buf, [4, 4, 4, 4, 4, 0, 0, 0, 0, 0]);
+    }
+
+    #[test]
+    #[allow(deprecated)]
+    fn broadcast() {
+        let mut buf1 = [0; 10];
+        let mut buf2 = [0; 10];
+        {
+            let mut ptr1: &mut [u8] = &mut buf1;
+            let mut ptr2: &mut [u8] = &mut buf2;
+
+            assert_eq!((&mut ptr1).broadcast(&mut ptr2)
+                                  .write(&[1, 2, 3]).unwrap(), 3);
+        }
+        assert_eq!(buf1, buf2);
+        assert_eq!(buf1, [1, 2, 3, 0, 0, 0, 0, 0, 0, 0]);
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/buffered.rs

@@ -0,0 +1,1148 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Buffering wrappers for I/O traits
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use marker::Reflect;
+use cmp;
+use error;
+use fmt;
+use io::{self, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a `Read` instance.
+/// For example, every call to `read` on `TcpStream` results in a system call.
+/// A `BufReader` performs large, infrequent reads on the underlying `Read`
+/// and maintains an in-memory buffer of the results.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut f = try!(File::open("log.txt"));
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = try!(reader.read_line(&mut line));
+/// println!("First line is {} bytes long", len);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufReader<R> {
+    inner: R,
+    buf: Box<[u8]>,
+    pos: usize,
+    cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+    /// Creates a new `BufReader` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: R) -> BufReader<R> {
+        BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufReader` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with ten bytes of capacity:
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::with_capacity(10, f);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+        BufReader {
+            inner: inner,
+            buf: vec![0; cap].into_boxed_slice(),
+            pos: 0,
+            cap: 0,
+        }
+    }
+
+    /// Gets a reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &R { &self.inner }
+
+    /// Gets a mutable reference to the underlying reader.
+    ///
+    /// It is inadvisable to directly read from the underlying reader.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+    /// Unwraps this `BufReader`, returning the underlying reader.
+    ///
+    /// Note that any leftover data in the internal buffer is lost.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::BufReader;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut f1 = try!(File::open("log.txt"));
+    /// let mut reader = BufReader::new(f1);
+    ///
+    /// let f2 = reader.into_inner();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> R { self.inner }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Read for BufReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        // If we don't have any buffered data and we're doing a massive read
+        // (larger than our internal buffer), bypass our internal buffer
+        // entirely.
+        if self.pos == self.cap && buf.len() >= self.buf.len() {
+            return self.inner.read(buf);
+        }
+        let nread = {
+            let mut rem = self.fill_buf()?;
+            rem.read(buf)?
+        };
+        self.consume(nread);
+        Ok(nread)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> BufRead for BufReader<R> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        // If we've reached the end of our internal buffer then we need to fetch
+        // some more data from the underlying reader.
+        if self.pos == self.cap {
+            self.cap = self.inner.read(&mut self.buf)?;
+            self.pos = 0;
+        }
+        Ok(&self.buf[self.pos..self.cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.pos = cmp::min(self.pos + amt, self.cap);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufReader")
+            .field("reader", &self.inner)
+            .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Seek> Seek for BufReader<R> {
+    /// Seek to an offset, in bytes, in the underlying reader.
+    ///
+    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// position the underlying reader would be at if the `BufReader` had no
+    /// internal buffer.
+    ///
+    /// Seeking always discards the internal buffer, even if the seek position
+    /// would otherwise fall within it. This guarantees that calling
+    /// `.unwrap()` immediately after a seek yields the underlying reader at
+    /// the same position.
+    ///
+    /// See `std::io::Seek` for more details.
+    ///
+    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// where `n` minus the internal buffer length underflows an `i64`, two
+    /// seeks will be performed instead of one. If the second seek returns
+    /// `Err`, the underlying reader will be left at the same position it would
+    /// have if you seeked to `SeekFrom::Current(0)`.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        let result: u64;
+        if let SeekFrom::Current(n) = pos {
+            let remainder = (self.cap - self.pos) as i64;
+            // it should be safe to assume that remainder fits within an i64 as the alternative
+            // means we managed to allocate 8 ebibytes and that's absurd.
+            // But it's not out of the realm of possibility for some weird underlying reader to
+            // support seeking by i64::min_value() so we need to handle underflow when subtracting
+            // remainder.
+            if let Some(offset) = n.checked_sub(remainder) {
+                result = self.inner.seek(SeekFrom::Current(offset))?;
+            } else {
+                // seek backwards by our remainder, and then by the offset
+                self.inner.seek(SeekFrom::Current(-remainder))?;
+                self.pos = self.cap; // empty the buffer
+                result = self.inner.seek(SeekFrom::Current(n))?;
+            }
+        } else {
+            // Seeking with Start/End doesn't care about our buffer length.
+            result = self.inner.seek(pos)?;
+        }
+        self.pos = self.cap; // empty the buffer
+        Ok(result)
+    }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements `Write`. For example, every call to `write` on `TcpStream`
+/// results in a system call. A `BufWriter` keeps an in-memory buffer of data
+/// and writes it to an underlying writer in large, infrequent batches.
+///
+/// The buffer will be written out when the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a `TcpStream`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 1..10 {
+///     stream.write(&[i]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct BufWriter<W: Write> {
+    inner: Option<W>,
+    buf: Vec<u8>,
+    // #30888: If the inner writer panics in a call to write, we don't want to
+    // write the buffered data a second time in BufWriter's destructor. This
+    // flag tells the Drop impl if it should skip the flush.
+    panicked: bool,
+}
+
+/// An error returned by `into_inner` which combines an error that
+/// happened while writing out the buffer, and the buffered writer object
+/// which may be used to recover from the condition.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// // do stuff with the stream
+///
+/// // we want to get our `TcpStream` back, so let's try:
+///
+/// let stream = match stream.into_inner() {
+///     Ok(s) => s,
+///     Err(e) => {
+///         // Here, e is an IntoInnerError
+///         panic!("An error occurred");
+///     }
+/// };
+/// ```
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+    /// Creates a new `BufWriter` with a default buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> BufWriter<W> {
+        BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+    }
+
+    /// Creates a new `BufWriter` with the specified buffer capacity.
+    ///
+    /// # Examples
+    ///
+    /// Creating a buffer with a buffer of a hundred bytes.
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+    /// let mut buffer = BufWriter::with_capacity(100, stream);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+        BufWriter {
+            inner: Some(inner),
+            buf: Vec::with_capacity(cap),
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        let mut written = 0;
+        let len = self.buf.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+            self.panicked = false;
+
+            match r {
+                Ok(0) => {
+                    ret = Err(Error::new(ErrorKind::WriteZero,
+                                         "failed to write the buffered data"));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => { ret = Err(e); break }
+
+            }
+        }
+        if written > 0 {
+            self.buf.drain(..written);
+        }
+        ret
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// It is inadvisable to directly write to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // we can use reference just like buffer
+    /// let reference = buffer.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+    /// Unwraps this `BufWriter`, returning the underlying writer.
+    ///
+    /// The buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // unwrap the TcpStream and flush the buffer
+    /// let stream = buffer.into_inner().unwrap();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+        match self.flush_buf() {
+            Err(e) => Err(IntoInnerError(self, e)),
+            Ok(()) => Ok(self.inner.take().unwrap())
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for BufWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        if self.buf.len() + buf.len() > self.buf.capacity() {
+            self.flush_buf()?;
+        }
+        if buf.len() >= self.buf.capacity() {
+            self.panicked = true;
+            let r = self.inner.as_mut().unwrap().write(buf);
+            self.panicked = false;
+            r
+        } else {
+            let amt = cmp::min(buf.len(), self.buf.capacity());
+            Write::write(&mut self.buf, &buf[..amt])
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf().and_then(|()| self.get_mut().flush())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("BufWriter")
+            .field("writer", &self.inner.as_ref().unwrap())
+            .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + Seek> Seek for BufWriter<W> {
+    /// Seek to the offset, in bytes, in the underlying writer.
+    ///
+    /// Seeking always writes out the internal buffer before seeking.
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Drop for BufWriter<W> {
+    fn drop(&mut self) {
+        if self.inner.is_some() && !self.panicked {
+            // dtors should not panic, so we ignore a failed flush
+            let _r = self.flush_buf();
+        }
+    }
+}
+
+impl<W> IntoInnerError<W> {
+    /// Returns the error which caused the call to `into_inner()` to fail.
+    ///
+    /// This error was returned when attempting to write the internal buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's log the inner error.
+    ///         //
+    ///         // We'll just 'log' to stdout for this example.
+    ///         println!("{}", e.error());
+    ///
+    ///         panic!("An unexpected error occurred.");
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn error(&self) -> &Error { &self.1 }
+
+    /// Returns the buffered writer instance which generated the error.
+    ///
+    /// The returned object can be used for error recovery, such as
+    /// re-inspecting the buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::io::BufWriter;
+    /// use std::net::TcpStream;
+    ///
+    /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+    ///
+    /// // do stuff with the stream
+    ///
+    /// // we want to get our `TcpStream` back, so let's try:
+    ///
+    /// let stream = match stream.into_inner() {
+    ///     Ok(s) => s,
+    ///     Err(e) => {
+    ///         // Here, e is an IntoInnerError, let's re-examine the buffer:
+    ///         let buffer = e.into_inner();
+    ///
+    ///         // do stuff to try to recover
+    ///
+    ///         // afterwards, let's just return the stream
+    ///         buffer.into_inner().unwrap()
+    ///     }
+    /// };
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> W { self.0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> From<IntoInnerError<W>> for Error {
+    fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Reflect + Send + fmt::Debug> error::Error for IntoInnerError<W> {
+    fn description(&self) -> &str {
+        error::Error::description(self.error())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W> fmt::Display for IntoInnerError<W> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.error().fmt(f)
+    }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = try!(File::create("poem.txt"));
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+///    file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = try!(File::open("poem.txt"));
+/// let mut contents = String::new();
+///
+/// try!(file.read_to_string(&mut contents));
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct LineWriter<W: Write> {
+    inner: BufWriter<W>,
+}
+
+impl<W: Write> LineWriter<W> {
+    /// Creates a new `LineWriter`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: W) -> LineWriter<W> {
+        // Lines typically aren't that long, don't use a giant buffer
+        LineWriter::with_capacity(1024, inner)
+    }
+
+    /// Creates a new `LineWriter` with a specified capacity for the internal
+    /// buffer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::with_capacity(100, file);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+        LineWriter { inner: BufWriter::with_capacity(cap, inner) }
+    }
+
+    /// Gets a reference to the underlying writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let file = LineWriter::new(file);
+    ///
+    /// let reference = file.get_ref();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+    /// Gets a mutable reference to the underlying writer.
+    ///
+    /// Caution must be taken when calling methods on the mutable reference
+    /// returned as extra writes could corrupt the output stream.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    /// let mut file = LineWriter::new(file);
+    ///
+    /// // we can use reference just like file
+    /// let reference = file.get_mut();
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+    /// Unwraps this `LineWriter`, returning the underlying writer.
+    ///
+    /// The internal buffer is written out before returning the writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::LineWriter;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let file = try!(File::create("poem.txt"));
+    ///
+    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///
+    /// let file: File = try!(writer.into_inner());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+        self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+            IntoInnerError(LineWriter { inner: buf }, e)
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> Write for LineWriter<W> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match memchr::memrchr(b'\n', buf) {
+            Some(i) => {
+                let n = self.inner.write(&buf[..i + 1])?;
+                if n != i + 1 || self.inner.flush().is_err() {
+                    // Do not return errors on partial writes.
+                    return Ok(n);
+                }
+                self.inner.write(&buf[i + 1..]).map(|i| n + i)
+            }
+            None => self.inner.write(buf),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("LineWriter")
+            .field("writer", &self.inner.inner)
+            .field("buffer",
+                   &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+    use sync::atomic::{AtomicUsize, Ordering};
+    use thread;
+    use test;
+
+    /// A dummy reader intended at testing short-reads propagation.
+    pub struct ShortReader {
+        lengths: Vec<usize>,
+    }
+
+    impl Read for ShortReader {
+        fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+            if self.lengths.is_empty() {
+                Ok(0)
+            } else {
+                Ok(self.lengths.remove(0))
+            }
+        }
+    }
+
+    #[test]
+    fn test_buffered_reader() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, inner);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 2);
+        let b: &[_] = &[0, 1];
+        assert_eq!(buf, b);
+
+        let mut buf = [0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[2];
+        assert_eq!(buf, b);
+
+        let mut buf = [0, 0, 0];
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[3, 0, 0];
+        assert_eq!(buf, b);
+
+        let nread = reader.read(&mut buf);
+        assert_eq!(nread.unwrap(), 1);
+        let b: &[_] = &[4, 0, 0];
+        assert_eq!(buf, b);
+
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buffered_reader_seek() {
+        let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+        let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+        assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+        assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+        assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+        reader.consume(1);
+        assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+    }
+
+    #[test]
+    fn test_buffered_reader_seek_underflow() {
+        // gimmick reader that yields its position modulo 256 for each byte
+        struct PositionReader {
+            pos: u64
+        }
+        impl Read for PositionReader {
+            fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+                let len = buf.len();
+                for x in buf {
+                    *x = self.pos as u8;
+                    self.pos = self.pos.wrapping_add(1);
+                }
+                Ok(len)
+            }
+        }
+        impl Seek for PositionReader {
+            fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+                match pos {
+                    SeekFrom::Start(n) => {
+                        self.pos = n;
+                    }
+                    SeekFrom::Current(n) => {
+                        self.pos = self.pos.wrapping_add(n as u64);
+                    }
+                    SeekFrom::End(n) => {
+                        self.pos = u64::max_value().wrapping_add(n as u64);
+                    }
+                }
+                Ok(self.pos)
+            }
+        }
+
+        let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+        assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+        assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // the following seek will require two underlying seeks
+        let expected = 9223372036854775802;
+        assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+        assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+        // seeking to 0 should empty the buffer.
+        assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+        assert_eq!(reader.get_ref().pos, expected);
+    }
+
+    #[test]
+    fn test_buffered_writer() {
+        let inner = Vec::new();
+        let mut writer = BufWriter::with_capacity(2, inner);
+
+        writer.write(&[0, 1]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.write(&[3]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[4]).unwrap();
+        writer.write(&[5]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+        writer.write(&[6]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+        writer.write(&[7, 8]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+        writer.write(&[9, 10, 11]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+    }
+
+    #[test]
+    fn test_buffered_writer_inner_flushes() {
+        let mut w = BufWriter::with_capacity(3, Vec::new());
+        w.write(&[0, 1]).unwrap();
+        assert_eq!(*w.get_ref(), []);
+        let w = w.into_inner().unwrap();
+        assert_eq!(w, [0, 1]);
+    }
+
+    #[test]
+    fn test_buffered_writer_seek() {
+        let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+        w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+        w.write_all(&[6, 7]).unwrap();
+        assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+        assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+        assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+        w.write_all(&[8, 9]).unwrap();
+        assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_read_until() {
+        let inner: &[u8] = &[0, 1, 2, 1, 0];
+        let mut reader = BufReader::with_capacity(2, inner);
+        let mut v = Vec::new();
+        reader.read_until(0, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(2, &mut v).unwrap();
+        assert_eq!(v, [1, 2]);
+        v.truncate(0);
+        reader.read_until(1, &mut v).unwrap();
+        assert_eq!(v, [1]);
+        v.truncate(0);
+        reader.read_until(8, &mut v).unwrap();
+        assert_eq!(v, [0]);
+        v.truncate(0);
+        reader.read_until(9, &mut v).unwrap();
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn test_line_buffer_fail_flush() {
+        // Issue #32085
+        struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+        impl<'a> Write for FailFlushWriter<'a> {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+                self.0.extend_from_slice(buf);
+                Ok(buf.len())
+            }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+            }
+        }
+
+        let mut buf = Vec::new();
+        {
+            let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+            let to_write = b"abc\ndef";
+            if let Ok(written) = writer.write(to_write) {
+                assert!(written < to_write.len(), "didn't flush on new line");
+                // PASS
+                return;
+            }
+        }
+        assert!(buf.is_empty(), "write returned an error but wrote data");
+    }
+
+    #[test]
+    fn test_line_buffer() {
+        let mut writer = LineWriter::new(Vec::new());
+        writer.write(&[0]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.write(&[1]).unwrap();
+        assert_eq!(*writer.get_ref(), []);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1]);
+        writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+        writer.flush().unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+        writer.write(&[3, b'\n']).unwrap();
+        assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+    }
+
+    #[test]
+    fn test_read_line() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let mut reader = BufReader::with_capacity(2, in_buf);
+        let mut s = String::new();
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "a\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "b\n");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "c");
+        s.truncate(0);
+        reader.read_line(&mut s).unwrap();
+        assert_eq!(s, "");
+    }
+
+    #[test]
+    fn test_lines() {
+        let in_buf: &[u8] = b"a\nb\nc";
+        let reader = BufReader::with_capacity(2, in_buf);
+        let mut it = reader.lines();
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    fn test_short_reads() {
+        let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+        let mut reader = BufReader::new(inner);
+        let mut buf = [0, 0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_char_buffered() {
+        let buf = [195, 159];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+    }
+
+    #[test]
+    fn test_chars() {
+        let buf = [195, 159, b'a'];
+        let reader = BufReader::with_capacity(1, &buf[..]);
+        let mut it = reader.chars();
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn dont_panic_in_drop_on_panicked_flush() {
+        struct FailFlushWriter;
+
+        impl Write for FailFlushWriter {
+            fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+            fn flush(&mut self) -> io::Result<()> {
+                Err(io::Error::last_os_error())
+            }
+        }
+
+        let writer = FailFlushWriter;
+        let _writer = BufWriter::new(writer);
+
+        // If writer panics *again* due to the flush error then the process will
+        // abort.
+        panic!();
+    }
+
+    #[test]
+    fn panic_in_write_doesnt_flush_in_drop() {
+        static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+        struct PanicWriter;
+
+        impl Write for PanicWriter {
+            fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+                WRITES.fetch_add(1, Ordering::SeqCst);
+                panic!();
+            }
+            fn flush(&mut self) -> io::Result<()> { Ok(()) }
+        }
+
+        thread::spawn(|| {
+            let mut writer = BufWriter::new(PanicWriter);
+            let _ = writer.write(b"hello world");
+            let _ = writer.flush();
+        }).join().unwrap_err();
+
+        assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+    }
+
+    #[bench]
+    fn bench_buffered_reader(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufReader::new(io::empty())
+        });
+    }
+
+    #[bench]
+    fn bench_buffered_writer(b: &mut test::Bencher) {
+        b.iter(|| {
+            BufWriter::new(io::sink())
+        });
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/cursor.rs

@@ -0,0 +1,585 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use prelude::v1::*;
+use io::prelude::*;
+
+use cmp;
+use io::{self, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`](trait.Seek.html) implementation.
+///
+/// Cursors are typically used with in-memory buffers to allow them to
+/// implement `Read` and/or `Write`, allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<Vec<u8>>` and `Cursor<&[u8]>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`][file] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+///     try!(writer.seek(SeekFrom::End(-10)));
+///
+///     for i in 0..10 {
+///         try!(writer.write(&[i]));
+///     }
+///
+///     // all went well
+///     Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = try!(File::create("foo.txt"));
+///
+/// try!(write_ten_bytes_at_end(&mut file));
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+///     // setting up a real File is much more slow than an in-memory buffer,
+///     // let's use a cursor instead
+///     use std::io::Cursor;
+///     let mut buff = Cursor::new(vec![0; 15]);
+///
+///     write_ten_bytes_at_end(&mut buff).unwrap();
+///
+///     assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+    inner: T,
+    pos: u64,
+}
+
+impl<T> Cursor<T> {
+    /// Creates a new cursor wrapping the provided underlying I/O object.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new(inner: T) -> Cursor<T> {
+        Cursor { pos: 0, inner: inner }
+    }
+
+    /// Consumes this cursor, returning the underlying value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let vec = buff.into_inner();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_inner(self) -> T { self.inner }
+
+    /// Gets a reference to the underlying value in this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_ref();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_ref(&self) -> &T { &self.inner }
+
+    /// Gets a mutable reference to the underlying value in this cursor.
+    ///
+    /// Care should be taken to avoid modifying the internal I/O state of the
+    /// underlying value as it may corrupt this cursor's position.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(Vec::new());
+    /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+    /// # force_inference(&buff);
+    ///
+    /// let reference = buff.get_mut();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+    /// Returns the current position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    /// use std::io::prelude::*;
+    /// use std::io::SeekFrom;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.seek(SeekFrom::Current(2)).unwrap();
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.seek(SeekFrom::Current(-1)).unwrap();
+    /// assert_eq!(buff.position(), 1);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn position(&self) -> u64 { self.pos }
+
+    /// Sets the position of this cursor.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Cursor;
+    ///
+    /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+    ///
+    /// assert_eq!(buff.position(), 0);
+    ///
+    /// buff.set_position(2);
+    /// assert_eq!(buff.position(), 2);
+    ///
+    /// buff.set_position(4);
+    /// assert_eq!(buff.position(), 4);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+    fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+        let pos = match style {
+            SeekFrom::Start(n) => { self.pos = n; return Ok(n) }
+            SeekFrom::End(n) => self.inner.as_ref().len() as i64 + n,
+            SeekFrom::Current(n) => self.pos as i64 + n,
+        };
+
+        if pos < 0 {
+            Err(Error::new(ErrorKind::InvalidInput,
+                           "invalid seek to a negative position"))
+        } else {
+            self.pos = pos as u64;
+            Ok(self.pos)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = Read::read(&mut self.fill_buf()?, buf)?;
+        self.pos += n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+        Ok(&self.inner.as_ref()[(amt as usize)..])
+    }
+    fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for Cursor<&'a mut [u8]> {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(data)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Cursor<Vec<u8>> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        // Make sure the internal buffer is as least as big as where we
+        // currently are
+        let pos = self.position();
+        let amt = pos.saturating_sub(self.inner.len() as u64);
+        // use `resize` so that the zero filling is as efficient as possible
+        let len = self.inner.len();
+        self.inner.resize(len + amt as usize, 0);
+
+        // Figure out what bytes will be used to overwrite what's currently
+        // there (left), and what will be appended on the end (right)
+        {
+            let pos = pos as usize;
+            let space = self.inner.len() - pos;
+            let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+            self.inner[pos..pos + left.len()].copy_from_slice(left);
+            self.inner.extend_from_slice(right);
+        }
+
+        // Bump us forward
+        self.set_position(pos + buf.len() as u64);
+        Ok(buf.len())
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "cursor_box_slice", since = "1.5.0")]
+impl Write for Cursor<Box<[u8]>> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let pos = cmp::min(self.pos, self.inner.len() as u64);
+        let amt = (&mut self.inner[(pos as usize)..]).write(buf)?;
+        self.pos += amt as u64;
+        Ok(amt)
+    }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use io::{Cursor, SeekFrom};
+    use vec::Vec;
+
+    #[test]
+    fn test_vec_writer() {
+        let mut writer = Vec::new();
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(writer, b);
+    }
+
+    #[test]
+    fn test_mem_writer() {
+        let mut writer = Cursor::new(Vec::new());
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn test_box_slice_writer() {
+        let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        assert_eq!(writer.write(&[]).unwrap(), 0);
+        assert_eq!(writer.position(), 8);
+
+        assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+        assert_eq!(writer.write(&[10]).unwrap(), 0);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(&**writer.get_ref(), b);
+    }
+
+    #[test]
+    fn test_buf_writer() {
+        let mut buf = [0 as u8; 9];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+            assert_eq!(writer.position(), 8);
+            assert_eq!(writer.write(&[]).unwrap(), 0);
+            assert_eq!(writer.position(), 8);
+
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
+        }
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_seek() {
+        let mut buf = [0 as u8; 8];
+        {
+            let mut writer = Cursor::new(&mut buf[..]);
+            assert_eq!(writer.position(), 0);
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+            assert_eq!(writer.position(), 2);
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
+            assert_eq!(writer.position(), 3);
+
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+            assert_eq!(writer.position(), 1);
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
+            assert_eq!(writer.position(), 2);
+
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+            assert_eq!(writer.position(), 7);
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
+            assert_eq!(writer.position(), 8);
+
+        }
+        let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+        assert_eq!(buf, b);
+    }
+
+    #[test]
+    fn test_buf_writer_error() {
+        let mut buf = [0 as u8; 2];
+        let mut writer = Cursor::new(&mut buf[..]);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_mem_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_boxed_slice_reader() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7).into_boxed_slice());
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
+        let mut v = Vec::new();
+        reader.read_to_end(&mut v).unwrap();
+        assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+    }
+
+    #[test]
+    fn test_slice_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = &mut &in_buf[..];
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.len(), 7);
+        let b: &[_] = &[0];
+        assert_eq!(&buf[..], b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.len(), 3);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(&buf[..], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_buf_reader() {
+        let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+        let mut reader = Cursor::new(&in_buf[..]);
+        let mut buf = [];
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.position(), 0);
+        let mut buf = [0];
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.position(), 1);
+        let b: &[_] = &[0];
+        assert_eq!(buf, b);
+        let mut buf = [0; 4];
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
+        assert_eq!(reader.position(), 5);
+        let b: &[_] = &[1, 2, 3, 4];
+        assert_eq!(buf, b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
+        let b: &[_] = &[5, 6, 7];
+        assert_eq!(&buf[..3], b);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+    }
+
+    #[test]
+    fn test_read_char() {
+        let b = &b"Vi\xE1\xBB\x87t"[..];
+        let mut c = Cursor::new(b).chars();
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
+    }
+
+    #[test]
+    fn test_read_bad_char() {
+        let b = &b"\x80"[..];
+        let mut c = Cursor::new(b).chars();
+        assert!(c.next().unwrap().is_err());
+    }
+
+    #[test]
+    fn seek_past_end() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec!(10));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+
+        let mut r = Cursor::new(vec![10].into_boxed_slice());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
+    }
+
+    #[test]
+    fn seek_before_0() {
+        let buf = [0xff];
+        let mut r = Cursor::new(&buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10));
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut buf = [0];
+        let mut r = Cursor::new(&mut buf[..]);
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+        let mut r = Cursor::new(vec!(10).into_boxed_slice());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+
+    #[test]
+    fn test_seekable_mem_writer() {
+        let mut writer = Cursor::new(Vec::<u8>::new());
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.position(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+        assert_eq!(writer.position(), 8);
+        let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+        assert_eq!(writer.position(), 0);
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+        assert_eq!(&writer.get_ref()[..], b);
+
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
+        let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+        assert_eq!(&writer.get_ref()[..], b);
+    }
+
+    #[test]
+    fn vec_seek_past_end() {
+        let mut r = Cursor::new(Vec::new());
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
+    }
+
+    #[test]
+    fn vec_seek_before_0() {
+        let mut r = Cursor::new(Vec::new());
+        assert!(r.seek(SeekFrom::End(-2)).is_err());
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/error.rs

@@ -0,0 +1,566 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use convert::Into;
+use error;
+use fmt;
+use marker::{Send, Sync};
+use option::Option::{self, Some, None};
+use result;
+use sys;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across `std::io` for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out `io::Error` directly and
+/// is otherwise a direct mapping to `Result`.
+///
+/// While usual Rust style is to import types directly, aliases of `Result`
+/// often are not, to make it easier to distinguish between them. `Result` is
+/// generally assumed to be `std::result::Result`, and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of `std::result::Result`.
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+///     let mut buffer = String::new();
+///
+///     try!(io::stdin().read_line(&mut buffer));
+///
+///     Ok(buffer)
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`ErrorKind`]: enum.ErrorKind.html
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Error {
+    repr: Repr,
+}
+
+enum Repr {
+    Os(i32),
+    Custom(Box<Custom>),
+}
+
+#[derive(Debug)]
+struct Custom {
+    kind: ErrorKind,
+    error: Box<error::Error+Send+Sync>,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[allow(deprecated)]
+pub enum ErrorKind {
+    /// An entity was not found, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotFound,
+    /// The operation lacked the necessary privileges to complete.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    PermissionDenied,
+    /// The connection was refused by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionRefused,
+    /// The connection was reset by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionReset,
+    /// The connection was aborted (terminated) by the remote server.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    ConnectionAborted,
+    /// The network operation failed because it was not connected yet.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    NotConnected,
+    /// A socket address could not be bound because the address is already in
+    /// use elsewhere.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrInUse,
+    /// A nonexistent interface was requested or the requested address was not
+    /// local.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AddrNotAvailable,
+    /// The operation failed because a pipe was closed.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    BrokenPipe,
+    /// An entity already exists, often a file.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    AlreadyExists,
+    /// The operation needs to block to complete, but the blocking operation was
+    /// requested to not occur.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WouldBlock,
+    /// A parameter was incorrect.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    InvalidInput,
+    /// Data not valid for the operation were encountered.
+    ///
+    /// Unlike `InvalidInput`, this typically means that the operation
+    /// parameters were valid, however the error was caused by malformed
+    /// input data.
+    ///
+    /// For example, a function that reads a file into a string will error with
+    /// `InvalidData` if the file's contents are not valid UTF-8.
+    #[stable(feature = "io_invalid_data", since = "1.2.0")]
+    InvalidData,
+    /// The I/O operation's timeout expired, causing it to be canceled.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    TimedOut,
+    /// An error returned when an operation could not be completed because a
+    /// call to `write` returned `Ok(0)`.
+    ///
+    /// This typically means that an operation could only succeed if it wrote a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// written.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    WriteZero,
+    /// This operation was interrupted.
+    ///
+    /// Interrupted operations can typically be retried.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Interrupted,
+    /// Any I/O error not part of this list.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Other,
+
+    /// An error returned when an operation could not be completed because an
+    /// "end of file" was reached prematurely.
+    ///
+    /// This typically means that an operation could only succeed if it read a
+    /// particular number of bytes but only a smaller number of bytes could be
+    /// read.
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    UnexpectedEof,
+
+    /// Any I/O error not part of this list.
+    #[unstable(feature = "io_error_internals",
+               reason = "better expressed through extensible enums that this \
+                         enum cannot be exhaustively matched against",
+               issue = "0")]
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+impl Error {
+    /// Creates a new I/O error from a known kind of error as well as an
+    /// arbitrary error payload.
+    ///
+    /// This function is used to generically create I/O errors which do not
+    /// originate from the OS itself. The `error` argument is an arbitrary
+    /// payload which will be contained in this `Error`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// // errors can be created from strings
+    /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+    ///
+    /// // errors can also be created from other errors
+    /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<E>(kind: ErrorKind, error: E) -> Error
+        where E: Into<Box<error::Error+Send+Sync>>
+    {
+        Self::_new(kind, error.into())
+    }
+
+    fn _new(kind: ErrorKind, error: Box<error::Error+Send+Sync>) -> Error {
+        Error {
+            repr: Repr::Custom(Box::new(Custom {
+                kind: kind,
+                error: error,
+            }))
+        }
+    }
+
+    /// Returns an error representing the last OS error which occurred.
+    ///
+    /// This function reads the value of `errno` for the target platform (e.g.
+    /// `GetLastError` on Windows) and will return a corresponding instance of
+    /// `Error` for the error code.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Error;
+    ///
+    /// println!("last OS error: {:?}", Error::last_os_error());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn last_os_error() -> Error {
+        Error::from_raw_os_error(sys::os::errno() as i32)
+    }
+
+    /// Creates a new instance of an `Error` from a particular OS error code.
+    ///
+    /// # Examples
+    ///
+    /// On Linux:
+    ///
+    /// ```
+    /// # if cfg!(target_os = "linux") {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(98);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    ///
+    /// On Windows:
+    ///
+    /// ```
+    /// # if cfg!(windows) {
+    /// use std::io;
+    ///
+    /// let error = io::Error::from_raw_os_error(10048);
+    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_raw_os_error(code: i32) -> Error {
+        Error { repr: Repr::Os(code) }
+    }
+
+    /// Returns the OS error that this error represents (if any).
+    ///
+    /// If this `Error` was constructed via `last_os_error` or
+    /// `from_raw_os_error`, then this function will return `Some`, otherwise
+    /// it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_os_error(err: &Error) {
+    ///     if let Some(raw_os_err) = err.raw_os_error() {
+    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///     } else {
+    ///         println!("Not an OS error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "raw OS error: ...".
+    ///     print_os_error(&Error::last_os_error());
+    ///     // Will print "Not an OS error".
+    ///     print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn raw_os_error(&self) -> Option<i32> {
+        match self.repr {
+            Repr::Os(i) => Some(i),
+            Repr::Custom(..) => None,
+        }
+    }
+
+    /// Returns a reference to the inner error wrapped by this error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {:?}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => Some(&*c.error),
+        }
+    }
+
+    /// Returns a mutable reference to the inner error wrapped by this error
+    /// (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    /// use std::{error, fmt};
+    /// use std::fmt::Display;
+    ///
+    /// #[derive(Debug)]
+    /// struct MyError {
+    ///     v: String,
+    /// }
+    ///
+    /// impl MyError {
+    ///     fn new() -> MyError {
+    ///         MyError {
+    ///             v: "oh no!".to_owned()
+    ///         }
+    ///     }
+    ///
+    ///     fn change_message(&mut self, new_message: &str) {
+    ///         self.v = new_message.to_owned();
+    ///     }
+    /// }
+    ///
+    /// impl error::Error for MyError {
+    ///     fn description(&self) -> &str { &self.v }
+    /// }
+    ///
+    /// impl Display for MyError {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "MyError: {}", &self.v)
+    ///     }
+    /// }
+    ///
+    /// fn change_error(mut err: Error) -> Error {
+    ///     if let Some(inner_err) = err.get_mut() {
+    ///         inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+    ///     }
+    ///     err
+    /// }
+    ///
+    /// fn print_error(err: &Error) {
+    ///     if let Some(inner_err) = err.get_ref() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(&change_error(Error::last_os_error()));
+    ///     // Will print "Inner error: ...".
+    ///     print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref mut c) => Some(&mut *c.error),
+        }
+    }
+
+    /// Consumes the `Error`, returning its inner error (if any).
+    ///
+    /// If this `Error` was constructed via `new` then this function will
+    /// return `Some`, otherwise it will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     if let Some(inner_err) = err.into_inner() {
+    ///         println!("Inner error: {}", inner_err);
+    ///     } else {
+    ///         println!("No inner error");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::Other, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "io_error_inner", since = "1.3.0")]
+    pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(c) => Some(c.error)
+        }
+    }
+
+    /// Returns the corresponding `ErrorKind` for this error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{Error, ErrorKind};
+    ///
+    /// fn print_error(err: Error) {
+    ///     println!("{:?}", err.kind());
+    /// }
+    ///
+    /// fn main() {
+    ///     // Will print "No inner error".
+    ///     print_error(Error::last_os_error());
+    ///     // Will print "Inner error: ...".
+    ///     print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn kind(&self) -> ErrorKind {
+        match self.repr {
+            Repr::Os(code) => sys::decode_error_kind(code),
+            Repr::Custom(ref c) => c.kind,
+        }
+    }
+}
+
+impl fmt::Debug for Repr {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Repr::Os(ref code) =>
+                fmt.debug_struct("Os").field("code", code)
+                   .field("message", &sys::os::error_string(*code)).finish(),
+            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match self.repr {
+            Repr::Os(code) => {
+                let detail = sys::os::error_string(code);
+                write!(fmt, "{} (os error {})", detail, code)
+            }
+            Repr::Custom(ref c) => c.error.fmt(fmt),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match self.repr {
+            Repr::Os(..) => match self.kind() {
+                ErrorKind::NotFound => "entity not found",
+                ErrorKind::PermissionDenied => "permission denied",
+                ErrorKind::ConnectionRefused => "connection refused",
+                ErrorKind::ConnectionReset => "connection reset",
+                ErrorKind::ConnectionAborted => "connection aborted",
+                ErrorKind::NotConnected => "not connected",
+                ErrorKind::AddrInUse => "address in use",
+                ErrorKind::AddrNotAvailable => "address not available",
+                ErrorKind::BrokenPipe => "broken pipe",
+                ErrorKind::AlreadyExists => "entity already exists",
+                ErrorKind::WouldBlock => "operation would block",
+                ErrorKind::InvalidInput => "invalid input parameter",
+                ErrorKind::InvalidData => "invalid data",
+                ErrorKind::TimedOut => "timed out",
+                ErrorKind::WriteZero => "write zero",
+                ErrorKind::Interrupted => "operation interrupted",
+                ErrorKind::Other => "other os error",
+                ErrorKind::UnexpectedEof => "unexpected end of file",
+                ErrorKind::__Nonexhaustive => unreachable!()
+            },
+            Repr::Custom(ref c) => c.error.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match self.repr {
+            Repr::Os(..) => None,
+            Repr::Custom(ref c) => c.error.cause(),
+        }
+    }
+}
+
+fn _assert_error_is_sync_send() {
+    fn _is_sync_send<T: Sync+Send>() {}
+    _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+    use prelude::v1::*;
+    use super::{Error, ErrorKind};
+    use error;
+    use fmt;
+    use sys::os::error_string;
+
+    #[test]
+    fn test_debug_error() {
+        let code = 6;
+        let msg = error_string(code);
+        let err = Error { repr: super::Repr::Os(code) };
+        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        assert_eq!(format!("{:?}", err), expected);
+    }
+
+    #[test]
+    fn test_downcasting() {
+        #[derive(Debug)]
+        struct TestError;
+
+        impl fmt::Display for TestError {
+            fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+                Ok(())
+            }
+        }
+
+        impl error::Error for TestError {
+            fn description(&self) -> &str {
+                "asdf"
+            }
+        }
+
+        // we have to call all of these UFCS style right now since method
+        // resolution won't implicitly drop the Send+Sync bounds
+        let mut err = Error::new(ErrorKind::Other, TestError);
+        assert!(err.get_ref().unwrap().is::<TestError>());
+        assert_eq!("asdf", err.get_ref().unwrap().description());
+        assert!(err.get_mut().unwrap().is::<TestError>());
+        let extracted = err.into_inner().unwrap();
+        extracted.downcast::<TestError>().unwrap();
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/impls.rs

@@ -0,0 +1,289 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use boxed::Box;
+use cmp;
+use io::{self, SeekFrom, Read, Write, Seek, BufRead, Error, ErrorKind};
+use fmt;
+use mem;
+use string::String;
+use vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read + ?Sized> Read for Box<R> {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        (**self).read(buf)
+    }
+
+    #[inline]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_to_end(buf)
+    }
+
+    #[inline]
+    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_to_string(buf)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        (**self).read_exact(buf)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<W: Write + ?Sized> Write for Box<W> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        (**self).write_all(buf)
+    }
+
+    #[inline]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+        (**self).write_fmt(fmt)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+    #[inline]
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+    #[inline]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+        (**self).read_until(byte, buf)
+    }
+
+    #[inline]
+    fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+        (**self).read_line(buf)
+    }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Read for &'a [u8] {
+    #[inline]
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let amt = cmp::min(buf.len(), self.len());
+        let (a, b) = self.split_at(amt);
+        buf[..amt].copy_from_slice(a);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+        if buf.len() > self.len() {
+            return Err(Error::new(ErrorKind::UnexpectedEof,
+                                  "failed to fill whole buffer"));
+        }
+        let (a, b) = self.split_at(buf.len());
+        buf.copy_from_slice(a);
+        *self = b;
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> BufRead for &'a [u8] {
+    #[inline]
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+    #[inline]
+    fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Write for &'a mut [u8] {
+    #[inline]
+    fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        let amt = cmp::min(data.len(), self.len());
+        let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+        a.copy_from_slice(&data[..amt]);
+        *self = b;
+        Ok(amt)
+    }
+
+    #[inline]
+    fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+        if self.write(data)? == data.len() {
+            Ok(())
+        } else {
+            Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+        }
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Vec<u8> {
+    #[inline]
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(buf);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use io::prelude::*;
+    use vec::Vec;
+    use test;
+
+    #[bench]
+    fn bench_read_slice(b: &mut test::Bencher) {
+        let buf = [5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_slice(b: &mut test::Bencher) {
+        let mut buf = [0; 1024];
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_read_vec(b: &mut test::Bencher) {
+        let buf = vec![5; 1024];
+        let mut dst = [0; 128];
+
+        b.iter(|| {
+            let mut rd = &buf[..];
+            for _ in 0..8 {
+                let _ = rd.read(&mut dst);
+                test::black_box(&dst);
+            }
+        })
+    }
+
+    #[bench]
+    fn bench_write_vec(b: &mut test::Bencher) {
+        let mut buf = Vec::with_capacity(1024);
+        let src = [5; 128];
+
+        b.iter(|| {
+            let mut wr = &mut buf[..];
+            for _ in 0..8 {
+                let _ = wr.write_all(&src);
+                test::black_box(&wr);
+            }
+        })
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/memchr.rs

@@ -0,0 +1,388 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// Original implementation taken from rust-memchr
+// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch
+
+
+
+/// A safe interface to `memchr`.
+///
+/// Returns the index corresponding to the first occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// memchr reduces to super-optimized machine code at around an order of
+/// magnitude faster than `haystack.iter().position(|&b| b == needle)`.
+/// (See benchmarks.)
+///
+/// # Example
+///
+/// This shows how to find the first position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memchr(b'k', haystack), Some(8));
+/// ```
+pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+    // libc memchr
+    #[cfg(not(target_os = "windows"))]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        let p = unsafe {
+            libc::memchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    // use fallback on windows, since it's faster
+    #[cfg(target_os = "windows")]
+    fn memchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memchr(needle, haystack)
+    }
+
+    memchr_specific(needle, haystack)
+}
+
+/// A safe interface to `memrchr`.
+///
+/// Returns the index corresponding to the last occurrence of `needle` in
+/// `haystack`, or `None` if one is not found.
+///
+/// # Example
+///
+/// This shows how to find the last position of a byte in a byte string.
+///
+/// ```rust,ignore
+/// use memchr::memrchr;
+///
+/// let haystack = b"the quick brown fox";
+/// assert_eq!(memrchr(b'o', haystack), Some(17));
+/// ```
+pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
+
+    #[cfg(target_os = "linux")]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use libc;
+
+        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
+        if haystack.is_empty() {return None}
+        let p = unsafe {
+            libc::memrchr(
+                haystack.as_ptr() as *const libc::c_void,
+                needle as libc::c_int,
+                haystack.len() as libc::size_t)
+        };
+        if p.is_null() {
+            None
+        } else {
+            Some(p as usize - (haystack.as_ptr() as usize))
+        }
+    }
+
+    #[cfg(not(target_os = "linux"))]
+    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
+        fallback::memrchr(needle, haystack)
+    }
+
+    memrchr_specific(needle, haystack)
+}
+
+#[allow(dead_code)]
+mod fallback {
+    use cmp;
+    use mem;
+
+    const LO_U64: u64 = 0x0101010101010101;
+    const HI_U64: u64 = 0x8080808080808080;
+
+    // use truncation
+    const LO_USIZE: usize = LO_U64 as usize;
+    const HI_USIZE: usize = HI_U64 as usize;
+
+    /// Return `true` if `x` contains any zero byte.
+    ///
+    /// From *Matters Computational*, J. Arndt
+    ///
+    /// "The idea is to subtract one from each of the bytes and then look for
+    /// bytes where the borrow propagated all the way to the most significant
+    /// bit."
+    #[inline]
+    fn contains_zero_byte(x: usize) -> bool {
+        x.wrapping_sub(LO_USIZE) & !x & HI_USIZE != 0
+    }
+
+    #[cfg(target_pointer_width = "32")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[inline]
+    fn repeat_byte(b: u8) -> usize {
+        let mut rep = (b as usize) << 8 | b as usize;
+        rep = rep << 16 | rep;
+        rep = rep << 32 | rep;
+        rep
+    }
+
+    /// Return the first index matching the byte `a` in `text`.
+    pub fn memchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned initial part, before the first word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the last remaining part, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search up to an aligned boundary
+        let align = (ptr as usize) & (usize_bytes- 1);
+        let mut offset;
+        if align > 0 {
+            offset = cmp::min(usize_bytes - align, len);
+            if let Some(index) = text[..offset].iter().position(|elt| *elt == x) {
+                return Some(index);
+            }
+        } else {
+            offset = 0;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        if len >= 2 * usize_bytes {
+            while offset <= len - 2 * usize_bytes {
+                unsafe {
+                    let u = *(ptr.offset(offset as isize) as *const usize);
+                    let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
+
+                    // break if there is a matching byte
+                    let zu = contains_zero_byte(u ^ repeated_x);
+                    let zv = contains_zero_byte(v ^ repeated_x);
+                    if zu || zv {
+                        break;
+                    }
+                }
+                offset += usize_bytes * 2;
+            }
+        }
+
+        // find the byte after the point the body loop stopped
+        text[offset..].iter().position(|elt| *elt == x).map(|i| offset + i)
+    }
+
+    /// Return the last index matching the byte `a` in `text`.
+    pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
+        // Scan for a single byte value by reading two `usize` words at a time.
+        //
+        // Split `text` in three parts
+        // - unaligned tail, after the last word aligned address in text
+        // - body, scan by 2 words at a time
+        // - the first remaining bytes, < 2 word size
+        let len = text.len();
+        let ptr = text.as_ptr();
+        let usize_bytes = mem::size_of::<usize>();
+
+        // search to an aligned boundary
+        let end_align = (ptr as usize + len) & (usize_bytes - 1);
+        let mut offset;
+        if end_align > 0 {
+            offset = len - cmp::min(usize_bytes - end_align, len);
+            if let Some(index) = text[offset..].iter().rposition(|elt| *elt == x) {
+                return Some(offset + index);
+            }
+        } else {
+            offset = len;
+        }
+
+        // search the body of the text
+        let repeated_x = repeat_byte(x);
+
+        while offset >= 2 * usize_bytes {
+            unsafe {
+                let u = *(ptr.offset(offset as isize - 2 * usize_bytes as isize) as *const usize);
+                let v = *(ptr.offset(offset as isize - usize_bytes as isize) as *const usize);
+
+                // break if there is a matching byte
+                let zu = contains_zero_byte(u ^ repeated_x);
+                let zv = contains_zero_byte(v ^ repeated_x);
+                if zu || zv {
+                    break;
+                }
+            }
+            offset -= 2 * usize_bytes;
+        }
+
+        // find the byte before the point the body loop stopped
+        text[..offset].iter().rposition(|elt| *elt == x)
+    }
+
+    // test fallback implementations on all platforms
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // test the implementations for the current plattform
+    use super::{memchr, memrchr};
+
+    #[test]
+    fn matches_one() {
+        assert_eq!(Some(0), memchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin() {
+        assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end() {
+        assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+    }
+
+    #[test]
+    fn matches_nul() {
+        assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul() {
+        assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+    }
+
+    #[test]
+    fn no_match_empty() {
+        assert_eq!(None, memchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match() {
+        assert_eq!(None, memchr(b'a', b"xyz"));
+    }
+
+    #[test]
+    fn matches_one_reversed() {
+        assert_eq!(Some(0), memrchr(b'a', b"a"));
+    }
+
+    #[test]
+    fn matches_begin_reversed() {
+        assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+    }
+
+    #[test]
+    fn matches_end_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+    }
+
+    #[test]
+    fn matches_nul_reversed() {
+        assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+    }
+
+    #[test]
+    fn matches_past_nul_reversed() {
+        assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+    }
+
+    #[test]
+    fn no_match_empty_reversed() {
+        assert_eq!(None, memrchr(b'a', b""));
+    }
+
+    #[test]
+    fn no_match_reversed() {
+        assert_eq!(None, memrchr(b'a', b"xyz"));
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/mod.rs

@@ -0,0 +1,1951 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`][read] and [`Write`][write] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! [read]: trait.Read.html
+//! [write]: trait.Write.html
+//!
+//! # Read and Write
+//!
+//! Because they are traits, `Read` and `Write` are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: `File`s, `TcpStream`s, and sometimes even `Vec<T>`s. For
+//! example, `Read` adds a `read()` method, which we can use on `File`s:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `Read` and `Write` are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the `Read` trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`][seek]
+//! and [`BufRead`][bufread]. Both of these build on top of a reader to control
+//! how the reading happens. `Seek` lets you control where the next byte is
+//! coming from:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut f = try!(File::open("foo.txt"));
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! try!(f.seek(SeekFrom::End(-10)));
+//!
+//! // read up to 10 bytes
+//! try!(f.read(&mut buffer));
+//!
+//! println!("The bytes: {:?}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [seek]: trait.Seek.html
+//! [bufread]: trait.BufRead.html
+//!
+//! `BufRead` uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, `BufReader` and `BufWriter`, which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, `BufReader` works with the `BufRead` trait to add extra
+//! methods to any reader:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! try!(reader.read_line(&mut buffer));
+//!
+//! println!("{}", buffer);
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! `BufWriter` doesn't add any new ways of writing; it just buffers every call
+//! to [`write()`][write()]:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::create("foo.txt"));
+//! {
+//!     let mut writer = BufWriter::new(f);
+//!
+//!     // write a byte to the buffer
+//!     try!(writer.write(&[42]));
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [write()]: trait.Write.html#tymethod.write
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! try!(io::stdin().read_line(&mut input));
+//!
+//! println!("You typed: {}", input.trim());
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::stdout().write(&[42]));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! Of course, using `io::stdout()` directly is less common than something like
+//! `println!`.
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, `Lines` is used to split over
+//! lines:
+//!
+//! ```
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! # fn foo() -> io::Result<()> {
+//! let f = try!(File::open("foo.txt"));
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//!     println!("{}", try!(line));
+//! }
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```
+//! use std::io;
+//!
+//! # fn foo() -> io::Result<()> {
+//! try!(io::copy(&mut io::stdin(), &mut io::stdout()));
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`][result]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`try!`][try] macro:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//!     let mut input = String::new();
+//!
+//!     try!(io::stdin().read_line(&mut input));
+//!
+//!     println!("You typed: {}", input.trim());
+//!
+//!     Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, `io::Result<()>`, is a very common type
+//! for functions which don't have a 'real' return value, but do want to return
+//! errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! [result]: type.Result.html
+//! [try]: ../macro.try!.html
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use cmp;
+use rustc_unicode::str as core_str;
+use error as std_error;
+use fmt;
+use iter::{Iterator};
+use marker::Sized;
+use ops::{Drop, FnOnce};
+use option::Option::{self, Some, None};
+use result::Result::{Ok, Err};
+use result;
+use string::String;
+use str;
+use vec::Vec;
+use memchr;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::buffered::IntoInnerError;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::cursor::Cursor;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::error::{Result, Error, ErrorKind};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{stdin, stdout, stderr, _print, Stdin, Stdout, Stderr};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::stdio::{StdoutLock, StderrLock, StdinLock};
+#[unstable(feature = "libstd_io_internals", issue = "0")]
+#[doc(no_inline, hidden)]
+pub use self::stdio::{set_panic, set_print};
+
+pub mod prelude;
+mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod lazy;
+mod util;
+mod stdio;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+//    checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+//    the function only *appends* bytes to the buffer. We'll get undefined
+//    behavior if existing bytes are overwritten to have non-UTF-8 data.
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+    where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+    struct Guard<'a> { s: &'a mut Vec<u8>, len: usize }
+        impl<'a> Drop for Guard<'a> {
+        fn drop(&mut self) {
+            unsafe { self.s.set_len(self.len); }
+        }
+    }
+
+    unsafe {
+        let mut g = Guard { len: buf.len(), s: buf.as_mut_vec() };
+        let ret = f(g.s);
+        if str::from_utf8(&g.s[g.len..]).is_err() {
+            ret.and_then(|_| {
+                Err(Error::new(ErrorKind::InvalidData,
+                               "stream did not contain valid UTF-8"))
+            })
+        } else {
+            g.len = g.s.len();
+            ret
+        }
+    }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+    let start_len = buf.len();
+    let mut len = start_len;
+    let mut new_write_size = 16;
+    let ret;
+    loop {
+        if len == buf.len() {
+            if new_write_size < DEFAULT_BUF_SIZE {
+                new_write_size *= 2;
+            }
+            buf.resize(len + new_write_size, 0);
+        }
+
+        match r.read(&mut buf[len..]) {
+            Ok(0) => {
+                ret = Ok(len - start_len);
+                break;
+            }
+            Ok(n) => len += n,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => {
+                ret = Err(e);
+                break;
+            }
+        }
+    }
+
+    buf.truncate(len);
+    ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are sometimes called 'readers'.
+///
+/// Readers are defined by one required method, `read()`. Each call to `read`
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of `read()`, giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to `read` may involve a system call, and
+/// therefore, using something that implements [`BufRead`][bufread], such as
+/// [`BufReader`][bufreader], will be more efficient.
+///
+/// [bufread]: trait.BufRead.html
+/// [bufreader]: struct.BufReader.html
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Read`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// try!(f.read(&mut buffer));
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// try!(f.read_to_end(&mut buffer));
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// try!(f.read_to_string(&mut buffer));
+///
+/// // and more! See the other methods for more details.
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Read {
+    /// Pull some bytes from this source into the specified buffer, returning
+    /// how many bytes were read.
+    ///
+    /// This function does not provide any guarantees about whether it blocks
+    /// waiting for data, but if an object needs to block for a read but cannot
+    /// it will typically signal this via an `Err` return value.
+    ///
+    /// If the return value of this method is `Ok(n)`, then it must be
+    /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+    /// that the buffer `buf` has been filled in with `n` bytes of data from this
+    /// source. If `n` is `0`, then it can indicate one of two scenarios:
+    ///
+    /// 1. This reader has reached its "end of file" and will likely no longer
+    ///    be able to produce bytes. Note that this does not mean that the
+    ///    reader will *always* no longer be able to produce bytes.
+    /// 2. The buffer specified was 0 bytes in length.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned. If an error is returned then it must be
+    /// guaranteed that no bytes were read.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read 10 bytes
+    /// try!(f.read(&mut buffer[..]));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// All bytes read from this source will be appended to the specified buffer
+    /// `buf`. This function will continuously call `read` to append more data to
+    /// `buf` until `read` returns either `Ok(0)` or an error of
+    /// non-`ErrorKind::Interrupted` kind.
+    ///
+    /// If successful, this function will return the total number of bytes read.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. Any bytes which have already been read will be appended to
+    /// `buf`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    ///
+    /// // read the whole file
+    /// try!(f.read_to_end(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+        read_to_end(self, buf)
+    }
+
+    /// Read all bytes until EOF in this source, placing them into `buf`.
+    ///
+    /// If successful, this function returns the number of bytes which were read
+    /// and appended to `buf`.
+    ///
+    /// # Errors
+    ///
+    /// If the data in this stream is *not* valid UTF-8 then an error is
+    /// returned and `buf` is unchanged.
+    ///
+    /// See [`read_to_end()`][readtoend] for other error semantics.
+    ///
+    /// [readtoend]: #method.read_to_end
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = String::new();
+    ///
+    /// try!(f.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we do *not* call `.read_to_end()` here. We are passing
+        // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+        // method to fill it up. An arbitrary implementation could overwrite the
+        // entire contents of the vector, not just append to it (which is what
+        // we are expecting).
+        //
+        // To prevent extraneously checking the UTF-8-ness of the entire buffer
+        // we pass it to our hardcoded `read_to_end` implementation which we
+        // know is guaranteed to only read data into the end of the buffer.
+        append_to_string(buf, |b| read_to_end(self, b))
+    }
+
+    /// Read the exact number of bytes required to fill `buf`.
+    ///
+    /// This function reads as many bytes as necessary to completely fill the
+    /// specified buffer `buf`.
+    ///
+    /// No guarantees are provided about the contents of `buf` when this
+    /// function is called, implementations cannot rely on any property of the
+    /// contents of `buf` being true. It is recommended that implementations
+    /// only write data to `buf` instead of reading its contents.
+    ///
+    /// # Errors
+    ///
+    /// If this function encounters an error of the kind
+    /// `ErrorKind::Interrupted` then the error is ignored and the operation
+    /// will continue.
+    ///
+    /// If this function encounters an "end of file" before completely filling
+    /// the buffer, it returns an error of the kind `ErrorKind::UnexpectedEof`.
+    /// The contents of `buf` are unspecified in this case.
+    ///
+    /// If any other read error is encountered then this function immediately
+    /// returns. The contents of `buf` are unspecified in this case.
+    ///
+    /// If this function returns an error, it is unspecified how many bytes it
+    /// has read, but it will never read more than would be necessary to
+    /// completely fill the buffer.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 10];
+    ///
+    /// // read exactly 10 bytes
+    /// try!(f.read_exact(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "read_exact", since = "1.6.0")]
+    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.read(buf) {
+                Ok(0) => break,
+                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        if !buf.is_empty() {
+            Err(Error::new(ErrorKind::UnexpectedEof,
+                           "failed to fill whole buffer"))
+        } else {
+            Ok(())
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Read`.
+    ///
+    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// current reader.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::Read;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = Vec::new();
+    /// let mut other_buffer = Vec::new();
+    ///
+    /// {
+    ///     let reference = f.by_ref();
+    ///
+    ///     // read at most 5 bytes
+    ///     try!(reference.take(5).read_to_end(&mut buffer));
+    ///
+    /// } // drop our &mut reference so we can use f again
+    ///
+    /// // original file still usable, read the rest
+    /// try!(f.read_to_end(&mut other_buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+    /// Transforms this `Read` instance to an `Iterator` over its bytes.
+    ///
+    /// The returned type implements `Iterator` where the `Item` is `Result<u8,
+    /// R::Err>`.  The yielded item is `Ok` if a byte was successfully read and
+    /// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
+    /// this iterator.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for byte in f.bytes() {
+    ///     println!("{}", byte.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn bytes(self) -> Bytes<Self> where Self: Sized {
+        Bytes { inner: self }
+    }
+
+    /// Transforms this `Read` instance to an `Iterator` over `char`s.
+    ///
+    /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+    /// sequence of characters. The returned iterator will return `None` once
+    /// EOF is reached for this reader. Otherwise each element yielded will be a
+    /// `Result<char, E>` where `E` may contain information about what I/O error
+    /// occurred or where decoding failed.
+    ///
+    /// Currently this adaptor will discard intermediate data read, and should
+    /// be avoided if this is not desired.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// #![feature(io)]
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    ///
+    /// for c in f.chars() {
+    ///     println!("{}", c.unwrap());
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[unstable(feature = "io", reason = "the semantics of a partial read/write \
+                                         of where errors happen is currently \
+                                         unclear and may change",
+               issue = "27802")]
+    fn chars(self) -> Chars<Self> where Self: Sized {
+        Chars { inner: self }
+    }
+
+    /// Creates an adaptor which will chain this stream with another.
+    ///
+    /// The returned `Read` instance will first read all bytes from this object
+    /// until EOF is encountered. Afterwards the output is equivalent to the
+    /// output of `next`.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f1 = try!(File::open("foo.txt"));
+    /// let mut f2 = try!(File::open("bar.txt"));
+    ///
+    /// let mut handle = f1.chain(f2);
+    /// let mut buffer = String::new();
+    ///
+    /// // read the value into a String. We could use any Read method here,
+    /// // this is just one example.
+    /// try!(handle.read_to_string(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+        Chain { first: self, second: next, done_first: false }
+    }
+
+    /// Creates an adaptor which will read at most `limit` bytes from it.
+    ///
+    /// This function returns a new instance of `Read` which will read at most
+    /// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
+    /// read errors will not count towards the number of bytes read and future
+    /// calls to `read` may succeed.
+    ///
+    /// # Examples
+    ///
+    /// [`File`][file]s implement `Read`:
+    ///
+    /// [file]: ../fs/struct.File.html
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let mut f = try!(File::open("foo.txt"));
+    /// let mut buffer = [0; 5];
+    ///
+    /// // read at most five bytes
+    /// let mut handle = f.take(5);
+    ///
+    /// try!(handle.read(&mut buffer));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+        Take { inner: self, limit: limit }
+    }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, `write()` and `flush()`:
+///
+/// * The `write()` method will attempt to write some data into the object,
+///   returning how many bytes were successfully written.
+///
+/// * The `flush()` method is useful for adaptors and explicit buffers
+///   themselves for ensuring that all buffered data has been pushed out to the
+///   'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout `std::io` take and provide types which implement the `Write`
+/// trait.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> std::io::Result<()> {
+/// let mut buffer = try!(File::create("foo.txt"));
+///
+/// try!(buffer.write(b"some bytes"));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Write {
+    /// Write a buffer into this object, returning how many bytes were written.
+    ///
+    /// This function will attempt to write the entire contents of `buf`, but
+    /// the entire write may not succeed, or the write may also generate an
+    /// error. A call to `write` represents *at most one* attempt to write to
+    /// any wrapped object.
+    ///
+    /// Calls to `write` are not guaranteed to block waiting for data to be
+    /// written, and a write which would otherwise block can be indicated through
+    /// an `Err` variant.
+    ///
+    /// If the return value is `Ok(n)` then it must be guaranteed that
+    /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+    /// underlying object is no longer able to accept bytes and will likely not
+    /// be able to in the future as well, or that the buffer provided is empty.
+    ///
+    /// # Errors
+    ///
+    /// Each call to `write` may generate an I/O error indicating that the
+    /// operation could not be completed. If an error is returned then no bytes
+    /// in the buffer were written to this writer.
+    ///
+    /// It is **not** considered an error if the entire buffer could not be
+    /// written to this writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+    /// Flush this output stream, ensuring that all intermediately buffered
+    /// contents reach their destination.
+    ///
+    /// # Errors
+    ///
+    /// It is considered an error if not all bytes could be written due to
+    /// I/O errors or EOF being reached.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::io::BufWriter;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
+    ///
+    /// try!(buffer.write(b"some bytes"));
+    /// try!(buffer.flush());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn flush(&mut self) -> Result<()>;
+
+    /// Attempts to write an entire buffer into this write.
+    ///
+    /// This method will continuously call `write` while there is more data to
+    /// write. This method will not return until the entire buffer has been
+    /// successfully written or an error occurs. The first error generated from
+    /// this method will be returned.
+    ///
+    /// # Errors
+    ///
+    /// This function will return the first error that `write` returns.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// try!(buffer.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+        while !buf.is_empty() {
+            match self.write(buf) {
+                Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+                                               "failed to write whole buffer")),
+                Ok(n) => buf = &buf[n..],
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
+            }
+        }
+        Ok(())
+    }
+
+    /// Writes a formatted string into this writer, returning any error
+    /// encountered.
+    ///
+    /// This method is primarily used to interface with the
+    /// [`format_args!`][formatargs] macro, but it is rare that this should
+    /// explicitly be called. The [`write!`][write] macro should be favored to
+    /// invoke this method instead.
+    ///
+    /// [formatargs]: ../macro.format_args!.html
+    /// [write]: ../macro.write!.html
+    ///
+    /// This function internally uses the [`write_all`][writeall] method on
+    /// this trait and hence will continuously write data so long as no errors
+    /// are received. This also means that partial writes are not indicated in
+    /// this signature.
+    ///
+    /// [writeall]: #method.write_all
+    ///
+    /// # Errors
+    ///
+    /// This function will return any I/O error reported while formatting.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// // this call
+    /// try!(write!(buffer, "{:.*}", 2, 1.234567));
+    /// // turns into this:
+    /// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+        // Create a shim which translates a Write to a fmt::Write and saves
+        // off I/O errors. instead of discarding them
+        struct Adaptor<'a, T: ?Sized + 'a> {
+            inner: &'a mut T,
+            error: Result<()>,
+        }
+
+        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+            fn write_str(&mut self, s: &str) -> fmt::Result {
+                match self.inner.write_all(s.as_bytes()) {
+                    Ok(()) => Ok(()),
+                    Err(e) => {
+                        self.error = Err(e);
+                        Err(fmt::Error)
+                    }
+                }
+            }
+        }
+
+        let mut output = Adaptor { inner: self, error: Ok(()) };
+        match fmt::write(&mut output, fmt) {
+            Ok(()) => Ok(()),
+            Err(..) => {
+                // check if the error came from the underlying `Write` or not
+                if output.error.is_err() {
+                    output.error
+                } else {
+                    Err(Error::new(ErrorKind::Other, "formatter error"))
+                }
+            }
+        }
+    }
+
+    /// Creates a "by reference" adaptor for this instance of `Write`.
+    ///
+    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// current writer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::Write;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> std::io::Result<()> {
+    /// let mut buffer = try!(File::create("foo.txt"));
+    ///
+    /// let reference = buffer.by_ref();
+    ///
+    /// // we can use reference just like our original buffer
+    /// try!(reference.write_all(b"some bytes"));
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut f = try!(File::open("foo.txt"));
+///
+/// // move the cursor 42 bytes from the start of the file
+/// try!(f.seek(SeekFrom::Start(42)));
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Seek {
+    /// Seek to an offset, in bytes, in a stream.
+    ///
+    /// A seek beyond the end of a stream is allowed, but implementation
+    /// defined.
+    ///
+    /// If the seek operation completed successfully,
+    /// this method returns the new position from the start of the stream.
+    /// That position can be used later with [`SeekFrom::Start`].
+    ///
+    /// # Errors
+    ///
+    /// Seeking to a negative offset is considered an error.
+    ///
+    /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub enum SeekFrom {
+    /// Set the offset to the provided number of bytes.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
+
+    /// Set the offset to the size of this object plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    End(#[stable(feature = "rust1", since = "1.0.0")] i64),
+
+    /// Set the offset to the current position plus the specified number of
+    /// bytes.
+    ///
+    /// It is possible to seek beyond the end of an object, but it's an error to
+    /// seek before byte 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Current(#[stable(feature = "rust1", since = "1.0.0")] i64),
+}
+
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+                                   -> Result<usize> {
+    let mut read = 0;
+    loop {
+        let (done, used) = {
+            let available = match r.fill_buf() {
+                Ok(n) => n,
+                Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                Err(e) => return Err(e)
+            };
+            match memchr::memchr(delim, available) {
+                Some(i) => {
+                    buf.extend_from_slice(&available[..i + 1]);
+                    (true, i + 1)
+                }
+                None => {
+                    buf.extend_from_slice(available);
+                    (false, available.len())
+                }
+            }
+        };
+        r.consume(used);
+        read += used;
+        if done || used == 0 {
+            return Ok(read);
+        }
+    }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
+///
+/// [readline]: #method.read_line
+/// [lines]: #method.lines
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+///     println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements `Read`, you can use the [`BufReader`
+/// type][bufreader] to turn it into a `BufRead`.
+///
+/// For example, [`File`][file] implements `Read`, but not `BufRead`.
+/// `BufReader` to the rescue!
+///
+/// [bufreader]: struct.BufReader.html
+/// [file]: ../fs/struct.File.html
+///
+/// ```
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// # fn foo() -> io::Result<()> {
+/// let f = try!(File::open("foo.txt"));
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+///     println!("{}", line.unwrap());
+/// }
+///
+/// # Ok(())
+/// # }
+/// ```
+///
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait BufRead: Read {
+    /// Fills the internal buffer of this object, returning the buffer contents.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`consume`][consume] method to function properly. When calling this
+    /// method, none of the contents will be "read" in the sense that later
+    /// calling `read` may return the same contents. As such, `consume` must be
+    /// called with the number of bytes that are consumed from this buffer to
+    /// ensure that the bytes are never returned twice.
+    ///
+    /// [consume]: #tymethod.consume
+    ///
+    /// An empty buffer returned indicates that the stream has reached EOF.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an I/O error if the underlying reader was
+    /// read, but returned an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    ///
+    /// // we can't have two `&mut` references to `stdin`, so use a block
+    /// // to end the borrow early.
+    /// let length = {
+    ///     let buffer = stdin.fill_buf().unwrap();
+    ///
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.len()
+    /// };
+    ///
+    /// // ensure the bytes we worked with aren't returned again later
+    /// stdin.consume(length);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn fill_buf(&mut self) -> Result<&[u8]>;
+
+    /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+    /// so they should no longer be returned in calls to `read`.
+    ///
+    /// This function is a lower-level call. It needs to be paired with the
+    /// [`fill_buf`][fillbuf] method to function properly. This function does
+    /// not perform any I/O, it simply informs this object that some amount of
+    /// its buffer, returned from `fill_buf`, has been consumed and should no
+    /// longer be returned. As such, this function may do odd things if
+    /// `fill_buf` isn't called before calling it.
+    ///
+    /// [fillbuf]: #tymethod.fill_buf
+    ///
+    /// The `amt` must be `<=` the number of bytes in the buffer returned by
+    /// `fill_buf`.
+    ///
+    /// # Examples
+    ///
+    /// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
+    /// that method's example includes an example of `consume()`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn consume(&mut self, amt: usize);
+
+    /// Read all bytes into `buf` until the delimiter `byte` is reached.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// delimiter or EOF is found. Once found, all bytes up to, and including,
+    /// the delimiter (if found) will be appended to `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function will ignore all instances of `ErrorKind::Interrupted` and
+    /// will otherwise return any errors returned by `fill_buf`.
+    ///
+    /// If an I/O error is encountered then all bytes read so far will be
+    /// present in `buf` and its length will have been adjusted appropriately.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read from standard input until we see an `a` byte.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// fn foo() -> io::Result<()> {
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = Vec::new();
+    ///
+    /// try!(stdin.read_until(b'a', &mut buffer));
+    ///
+    /// println!("{:?}", buffer);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+        read_until(self, byte, buf)
+    }
+
+    /// Read all bytes until a newline (the 0xA byte) is reached, and append
+    /// them to the provided buffer.
+    ///
+    /// This function will read bytes from the underlying stream until the
+    /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+    /// up to, and including, the delimiter (if found) will be appended to
+    /// `buf`.
+    ///
+    /// If this reader is currently at EOF then this function will not modify
+    /// `buf` and will return `Ok(n)` where `n` is the number of bytes which
+    /// were read.
+    ///
+    /// # Errors
+    ///
+    /// This function has the same error semantics as `read_until` and will also
+    /// return an error if the read bytes are not valid UTF-8. If an I/O error
+    /// is encountered then `buf` may contain some bytes already read in the
+    /// event that all data read so far was valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read all of the lines from standard input. If we were to do this in
+    /// an actual project, the [`lines()`][lines] method would be easier, of
+    /// course.
+    ///
+    /// [lines]: #method.lines
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    /// let mut stdin = stdin.lock();
+    /// let mut buffer = String::new();
+    ///
+    /// while stdin.read_line(&mut buffer).unwrap() > 0 {
+    ///     // work with buffer
+    ///     println!("{:?}", buffer);
+    ///
+    ///     buffer.clear();
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+        // Note that we are not calling the `.read_until` method here, but
+        // rather our hardcoded implementation. For more details as to why, see
+        // the comments in `read_to_end`.
+        append_to_string(buf, |b| read_until(self, b'\n', b))
+    }
+
+    /// Returns an iterator over the contents of this reader split on the byte
+    /// `byte`.
+    ///
+    /// The iterator returned from this function will return instances of
+    /// `io::Result<Vec<u8>>`. Each vector returned will *not* have the
+    /// delimiter byte at the end.
+    ///
+    /// This function will yield errors whenever `read_until` would have also
+    /// yielded an error.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`. In this example, we'll
+    /// read some input from standard input, splitting on commas.
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for content in stdin.lock().split(b',') {
+    ///     println!("{:?}", content.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+        Split { buf: self, delim: byte }
+    }
+
+    /// Returns an iterator over the lines of this reader.
+    ///
+    /// The iterator returned from this function will yield instances of
+    /// `io::Result<String>`. Each string returned will *not* have a newline
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+    ///
+    /// # Examples
+    ///
+    /// A locked standard input implements `BufRead`:
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    ///
+    /// let stdin = io::stdin();
+    ///
+    /// for line in stdin.lock().lines() {
+    ///     println!("{}", line.unwrap());
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn lines(self) -> Lines<Self> where Self: Sized {
+        Lines { buf: self }
+    }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain()`][chain] on a reader.
+/// Please see the documentation of `chain()` for more details.
+///
+/// [chain]: trait.Read.html#method.chain
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<T, U> {
+    first: T,
+    second: U,
+    done_first: bool,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read, U: Read> Read for Chain<T, U> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        if !self.done_first {
+            match self.first.read(buf)? {
+                0 => { self.done_first = true; }
+                n => return Ok(n),
+            }
+        }
+        self.second.read(buf)
+    }
+}
+
+#[stable(feature = "chain_bufread", since = "1.9.0")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        if !self.done_first {
+            match self.first.fill_buf()? {
+                buf if buf.len() == 0 => { self.done_first = true; }
+                buf => return Ok(buf),
+            }
+        }
+        self.second.fill_buf()
+    }
+
+    fn consume(&mut self, amt: usize) {
+        if !self.done_first {
+            self.first.consume(amt)
+        } else {
+            self.second.consume(amt)
+        }
+    }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take()`][take] on a reader.
+/// Please see the documentation of `take()` for more details.
+///
+/// [take]: trait.Read.html#method.take
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<T> {
+    inner: T,
+    limit: u64,
+}
+
+impl<T> Take<T> {
+    /// Returns the number of bytes that can be read before this instance will
+    /// return EOF.
+    ///
+    /// # Note
+    ///
+    /// This instance may reach EOF after reading fewer bytes than indicated by
+    /// this method if the underlying `Read` instance reaches EOF.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io;
+    /// use std::io::prelude::*;
+    /// use std::fs::File;
+    ///
+    /// # fn foo() -> io::Result<()> {
+    /// let f = try!(File::open("foo.txt"));
+    ///
+    /// // read at most five bytes
+    /// let handle = f.take(5);
+    ///
+    /// println!("limit: {}", handle.limit());
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn limit(&self) -> u64 { self.limit }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Read> Read for Take<T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(0);
+        }
+
+        let max = cmp::min(buf.len() as u64, self.limit) as usize;
+        let n = self.inner.read(&mut buf[..max])?;
+        self.limit -= n as u64;
+        Ok(n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: BufRead> BufRead for Take<T> {
+    fn fill_buf(&mut self) -> Result<&[u8]> {
+        // Don't call into inner reader at all at EOF because it may still block
+        if self.limit == 0 {
+            return Ok(&[]);
+        }
+
+        let buf = self.inner.fill_buf()?;
+        let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+        Ok(&buf[..cap])
+    }
+
+    fn consume(&mut self, amt: usize) {
+        // Don't let callers reset the limit by passing an overlarge value
+        let amt = cmp::min(amt as u64, self.limit) as usize;
+        self.limit -= amt as u64;
+        self.inner.consume(amt);
+    }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+    let mut buf = [0];
+    loop {
+        return match reader.read(&mut buf) {
+            Ok(0) => None,
+            Ok(..) => Some(Ok(buf[0])),
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => Some(Err(e)),
+        };
+    }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes()`][bytes] on a reader.
+/// Please see the documentation of `bytes()` for more details.
+///
+/// [bytes]: trait.Read.html#method.bytes
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bytes<R> {
+    inner: R,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<R: Read> Iterator for Bytes<R> {
+    type Item = Result<u8>;
+
+    fn next(&mut self) -> Option<Result<u8>> {
+        read_one_byte(&mut self.inner)
+    }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars()`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub struct Chars<R> {
+    inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+pub enum CharsError {
+    /// Variant representing that the underlying stream was read successfully
+    /// but it did not contain valid utf8 data.
+    NotUtf8,
+
+    /// Variant representing that an I/O error occurred.
+    Other(Error),
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl<R: Read> Iterator for Chars<R> {
+    type Item = result::Result<char, CharsError>;
+
+    fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+        let first_byte = match read_one_byte(&mut self.inner) {
+            None => return None,
+            Some(Ok(b)) => b,
+            Some(Err(e)) => return Some(Err(CharsError::Other(e))),
+        };
+        let width = core_str::utf8_char_width(first_byte);
+        if width == 1 { return Some(Ok(first_byte as char)) }
+        if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+        let mut buf = [first_byte, 0, 0, 0];
+        {
+            let mut start = 1;
+            while start < width {
+                match self.inner.read(&mut buf[start..width]) {
+                    Ok(0) => return Some(Err(CharsError::NotUtf8)),
+                    Ok(n) => start += n,
+                    Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+                    Err(e) => return Some(Err(CharsError::Other(e))),
+                }
+            }
+        }
+        Some(match str::from_utf8(&buf[..width]).ok() {
+            Some(s) => Ok(s.chars().next().unwrap()),
+            None => Err(CharsError::NotUtf8),
+        })
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl std_error::Error for CharsError {
+    fn description(&self) -> &str {
+        match *self {
+            CharsError::NotUtf8 => "invalid utf8 encoding",
+            CharsError::Other(ref e) => std_error::Error::description(e),
+        }
+    }
+    fn cause(&self) -> Option<&std_error::Error> {
+        match *self {
+            CharsError::NotUtf8 => None,
+            CharsError::Other(ref e) => e.cause(),
+        }
+    }
+}
+
+#[unstable(feature = "io", reason = "awaiting stability of Read::chars",
+           issue = "27802")]
+impl fmt::Display for CharsError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            CharsError::NotUtf8 => {
+                "byte stream did not contain valid utf8".fmt(f)
+            }
+            CharsError::Other(ref e) => e.fmt(f),
+        }
+    }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split()`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<B> {
+    buf: B,
+    delim: u8,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Split<B> {
+    type Item = Result<Vec<u8>>;
+
+    fn next(&mut self) -> Option<Result<Vec<u8>>> {
+        let mut buf = Vec::new();
+        match self.buf.read_until(self.delim, &mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf[buf.len() - 1] == self.delim {
+                    buf.pop();
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines()`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Lines<B> {
+    buf: B,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: BufRead> Iterator for Lines<B> {
+    type Item = Result<String>;
+
+    fn next(&mut self) -> Option<Result<String>> {
+        let mut buf = String::new();
+        match self.buf.read_line(&mut buf) {
+            Ok(0) => None,
+            Ok(_n) => {
+                if buf.ends_with("\n") {
+                    buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
+                }
+                Some(Ok(buf))
+            }
+            Err(e) => Some(Err(e))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+    use io::prelude::*;
+    use io;
+    use super::Cursor;
+    use test;
+    use super::repeat;
+
+    #[test]
+    fn read_until() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+        assert_eq!(v, b"12");
+
+        let mut buf = Cursor::new(&b"1233"[..]);
+        let mut v = Vec::new();
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+        assert_eq!(v, b"123");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+        assert_eq!(v, b"3");
+        v.truncate(0);
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+        assert_eq!(v, []);
+    }
+
+    #[test]
+    fn split() {
+        let buf = Cursor::new(&b"12"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"1233"[..]);
+        let mut s = buf.split(b'3');
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_line() {
+        let mut buf = Cursor::new(&b"12"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+        assert_eq!(v, "12");
+
+        let mut buf = Cursor::new(&b"12\n\n"[..]);
+        let mut v = String::new();
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+        assert_eq!(v, "12\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+        assert_eq!(v, "\n");
+        v.truncate(0);
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+    }
+
+    #[test]
+    fn lines() {
+        let buf = Cursor::new(&b"12\r"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+        assert!(s.next().is_none());
+
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
+        let mut s = buf.lines();
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
+    }
+
+    #[test]
+    fn read_to_end() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+        assert_eq!(v, []);
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = Vec::new();
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+        assert_eq!(v, b"1");
+
+        let cap = 1024 * 1024;
+        let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+        let mut v = Vec::new();
+        let (a, b) = data.split_at(data.len() / 2);
+        assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+        assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+        assert_eq!(v, data);
+    }
+
+    #[test]
+    fn read_to_string() {
+        let mut c = Cursor::new(&b""[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+        assert_eq!(v, "");
+
+        let mut c = Cursor::new(&b"1"[..]);
+        let mut v = String::new();
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+        assert_eq!(v, "1");
+
+        let mut c = Cursor::new(&b"\xff"[..]);
+        let mut v = String::new();
+        assert!(c.read_to_string(&mut v).is_err());
+    }
+
+    #[test]
+    fn read_exact() {
+        let mut buf = [0; 4];
+
+        let mut c = Cursor::new(&b""[..]);
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+    }
+
+    #[test]
+    fn read_exact_slice() {
+        let mut buf = [0; 4];
+
+        let mut c = &b""[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+
+        let mut c = &b"123"[..];
+        assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+                   io::ErrorKind::UnexpectedEof);
+        // make sure the optimized (early returning) method is being used
+        assert_eq!(&buf, &[0; 4]);
+
+        let mut c = &b"1234"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"1234");
+
+        let mut c = &b"56789"[..];
+        c.read_exact(&mut buf).unwrap();
+        assert_eq!(&buf, b"5678");
+        assert_eq!(c, b"9");
+    }
+
+    #[test]
+    fn take_eof() {
+        struct R;
+
+        impl Read for R {
+            fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+        }
+        impl BufRead for R {
+            fn fill_buf(&mut self) -> io::Result<&[u8]> {
+                Err(io::Error::new(io::ErrorKind::Other, ""))
+            }
+            fn consume(&mut self, _amt: usize) { }
+        }
+
+        let mut buf = [0; 1];
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+        assert_eq!(b"", R.take(0).fill_buf().unwrap());
+    }
+
+    fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+        let mut cat = Vec::new();
+        loop {
+            let consume = {
+                let buf1 = br1.fill_buf().unwrap();
+                let buf2 = br2.fill_buf().unwrap();
+                let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+                assert_eq!(buf1[..minlen], buf2[..minlen]);
+                cat.extend_from_slice(&buf1[..minlen]);
+                minlen
+            };
+            if consume == 0 {
+                break;
+            }
+            br1.consume(consume);
+            br2.consume(consume);
+        }
+        assert_eq!(br1.fill_buf().unwrap().len(), 0);
+        assert_eq!(br2.fill_buf().unwrap().len(), 0);
+        assert_eq!(&cat[..], &exp[..])
+    }
+
+    #[test]
+    fn chain_bufread() {
+        let testdata = b"ABCDEFGHIJKL";
+        let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+                                     .chain(&testdata[6..9])
+                                     .chain(&testdata[9..]);
+        let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+                                     .chain(&testdata[8..]);
+        cmp_bufread(chain1, chain2, &testdata[..]);
+    }
+
+    #[bench]
+    fn bench_read_to_end(b: &mut test::Bencher) {
+        b.iter(|| {
+            let mut lr = repeat(1).take(10000000);
+            let mut vec = Vec::with_capacity(1024);
+            super::read_to_end(&mut lr, &mut vec)
+        });
+    }
+}

src/fda473f00fa07b9a8246b104396f9922e54bff16/prelude.rs

@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use super::{Read, Write, BufRead, Seek};

src/fda473f00fa07b9a8246b104396f9922e54bff16/util.rs

@@ -0,0 +1,217 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(missing_copy_implementations)]
+
+use io::{self, Read, Write, ErrorKind, BufRead};
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// # fn foo() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// try!(io::copy(&mut reader, &mut writer));
+///
+/// assert_eq!(reader, &writer[..]);
+/// # Ok(())
+/// # }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+    where R: Read, W: Write
+{
+    let mut buf = [0; super::DEFAULT_BUF_SIZE];
+    let mut written = 0;
+    loop {
+        let len = match reader.read(&mut buf) {
+            Ok(0) => return Ok(written),
+            Ok(len) => len,
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        };
+        writer.write_all(&buf[..len])?;
+        written += len as u64;
+    }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty()`][empty]. Please see
+/// the documentation of `empty()` for more details.
+///
+/// [empty]: fn.empty.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return `Ok(0)`.
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Empty {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl BufRead for Empty {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+    fn consume(&mut self, _n: usize) {}
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat()`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Read for Repeat {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        for slot in &mut *buf {
+            *slot = self.byte;
+        }
+        Ok(buf.len())
+    }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink()`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Write for Sink {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+
+    use io::prelude::*;
+    use io::{copy, sink, empty, repeat};
+
+    #[test]
+    fn copy_copies() {
+        let mut r = repeat(0).take(4);
+        let mut w = sink();
+        assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+        let mut r = repeat(0).take(1 << 17);
+        assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+    }
+
+    #[test]
+    fn sink_sinks() {
+        let mut s = sink();
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+    }
+
+    #[test]
+    fn empty_reads() {
+        let mut e = empty();
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+    }
+
+    #[test]
+    fn repeat_repeats() {
+        let mut r = repeat(4);
+        let mut b = [0; 1024];
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
+        assert!(b.iter().all(|b| *b == 4));
+    }
+
+    #[test]
+    fn take_some_bytes() {
+        assert_eq!(repeat(4).take(100).bytes().count(), 100);
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+        assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+    }
+}