* add strtok_r

src/string/src/lib.rs

@@ -352,17 +352,46 @@ pub extern "C" fn strtok(s1: *mut c_char, delimiter: *const c_char) -> *mut c_ch
 
         return token;
     }
-
-    ptr::null_mut()
 }
 
 #[no_mangle]
 pub extern "C" fn strtok_r(
     s: *mut c_char,
-    sep: *const c_char,
+    delimiter: *const c_char,
     lasts: *mut *mut c_char,
 ) -> *mut c_char {
-    unimplemented!();
+    // Loosely based on GLIBC implementation
+    unsafe {
+        let mut haystack = s;
+        if haystack.is_null() {
+            if (*lasts).is_null() {
+                return ptr::null_mut();
+            }
+            haystack = *lasts;
+        }
+
+        // Skip past any extra delimiter left over from previous call
+        haystack = haystack.add(strspn(haystack, delimiter));
+        if *haystack == 0 {
+            haystack = ptr::null_mut();
+            *lasts = ptr::null_mut();
+            return ptr::null_mut();
+        }
+
+        // Build token by injecting null byte into delimiter
+        let token = haystack;
+        haystack = strpbrk(token, delimiter);
+        if !haystack.is_null() {
+            haystack.write(0);
+            haystack = haystack.add(1);
+            *lasts = haystack;
+        } else {
+            haystack = ptr::null_mut();
+            *lasts = ptr::null_mut();
+        }
+
+        return token;
+    }
 }
 
 #[no_mangle]

tests/Makefile

@@ -30,6 +30,7 @@ EXPECT_BINS=\
 	string/strstr \
 	string/strpbrk \
 	string/strtok \
+	string/strtok_r \
 	unlink \
 	waitpid \
 	write

tests/expected/string/strtok_r.stdout

@@ -0,0 +1,2 @@
+I'd_just_like_to_interject_for_a_moment.__What_you're_referring_to_as_Linux,
+is_in_fact,_GNU/Linux,_or_as_I've_recently_taken_to_calling_it,_GNU_plus_Linux.

tests/string/strtok_r.c

@@ -0,0 +1,18 @@
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char* argv[]) {
+    char source[] = "I'd just like to interject for a moment.  What you're referring to as Linux, "
+                    "is in fact, GNU/Linux, or as I've recently taken to calling it, GNU plus Linux.\n";
+    char* sp;
+
+    char* token = strtok_r(source, " ", &sp);
+    while (token) {
+        printf("%s", token);
+        if (token = strtok_r(NULL, " ", &sp)) {
+            printf("_");
+        }
+    }
+
+    return 0;
+}