Merge pull request yuin#287 from jlauinger/fix-unsafe-slice-cast

Fix possible memory confusion in unsafe slice cast

Author: yuin

utils.go

@@ -255,8 +255,11 @@ func strCmp(s1, s2 string) int {
 	}
 }
 
-func unsafeFastStringToReadOnlyBytes(s string) []byte {
+func unsafeFastStringToReadOnlyBytes(s string) (bs []byte) {
 	sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
-	bh := reflect.SliceHeader{Data: sh.Data, Len: sh.Len, Cap: sh.Len}
-	return *(*[]byte)(unsafe.Pointer(&bh))
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&bs))
+	bh.Data = sh.Data
+	bh.Cap = sh.Len
+	bh.Len = sh.Len
+	return
 }