code review 4711045: runtime: improve Linux mutex

src/pkg/runtime/string.goc

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package runtime
 #include "runtime.h"
 #include "malloc.h"
 
 String  runtime·emptystring;
 
@@ skipping 175 matching lines @@
                 c2 = s2[i];
                 if(c1 < c2)
                         return -1;
                 if(c1 > c2)
                         return +1;
                 if(c1 == 0)
                         return 0;
         }
 }
 
+byte*
+runtime·strstr(byte *s1, byte *s2)
+{
+        byte *sp1, *sp2;
+
+        if(*s2 == 0)
+                return s1;
+        for(; *s1; s1++) {
+                if(*s1 != *s2)
+                        continue;
+                sp1 = s1;
+                sp2 = s2;
+                for(;;) {
+                        if(*sp2 == 0)
+                                return s1;
+                        if(*sp1++ != *sp2++)
+                                break;
+                }
+        }
+        return nil;
+}
+
 func slicestring(si String, lindex int32, hindex int32) (so String) {
         int32 l;
 
         if(lindex < 0 || lindex > si.len ||
            hindex < lindex || hindex > si.len) {
                 runtime·panicslice();
         }
 
         l = hindex-lindex;
         so.str = si.str + lindex;
@@ skipping 113 matching lines @@
         if(retv < Runeself) {
                 retk = k+1;
                 goto out;
         }
 
         // multi-char rune
         retk = k + runtime·charntorune(&retv, s.str+k, s.len-k);
 
 out:
 }