libgo/runtime/go-strplus.c

   1 /* go-strplus.c -- the go string append function.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include "go-string.h"
   8 #include "runtime.h"
   9 #include "arch.h"
  10 #include "malloc.h"
  11
  12 struct __go_string
  13 __go_string_plus (struct __go_string s1, struct __go_string s2)
  14 {
  15   int len;
  16   unsigned char *retdata;
  17   struct __go_string ret;
  18
  19   if (s1.__length == 0)
  20     return s2;
  21   else if (s2.__length == 0)
  22     return s1;
  23
  24   len = s1.__length + s2.__length;
  25   retdata = runtime_mallocgc (len, FlagNoPointers, 1, 0);
  26   __builtin_memcpy (retdata, s1.__data, s1.__length);
  27   __builtin_memcpy (retdata + s1.__length, s2.__data, s2.__length);
  28   ret.__data = retdata;
  29   ret.__length = len;
  30   return ret;
  31 }