libgo/runtime/go-int-to-string.c

   1 /* go-int-to-string.c -- convert an integer to a string in Go.
   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 "malloc.h"
  10
  11 struct __go_string
  12 __go_int_to_string (int v)
  13 {
  14   char buf[4];
  15   int len;
  16   unsigned char *retdata;
  17   struct __go_string ret;
  18
  19   if (v <= 0x7f)
  20     {
  21       buf[0] = v;
  22       len = 1;
  23     }
  24   else if (v <= 0x7ff)
  25     {
  26       buf[0] = 0xc0 + (v >> 6);
  27       buf[1] = 0x80 + (v & 0x3f);
  28       len = 2;
  29     }
  30   else
  31     {
  32       /* If the value is out of range for UTF-8, turn it into the
  33          "replacement character".  */
  34       if (v > 0x10ffff)
  35         v = 0xfffd;
  36
  37       if (v <= 0xffff)
  38         {
  39           buf[0] = 0xe0 + (v >> 12);
  40           buf[1] = 0x80 + ((v >> 6) & 0x3f);
  41           buf[2] = 0x80 + (v & 0x3f);
  42           len = 3;
  43         }
  44       else
  45         {
  46           buf[0] = 0xf0 + (v >> 18);
  47           buf[1] = 0x80 + ((v >> 12) & 0x3f);
  48           buf[2] = 0x80 + ((v >> 6) & 0x3f);
  49           buf[3] = 0x80 + (v & 0x3f);
  50           len = 4;
  51         }
  52     }
  53
  54   retdata = runtime_mallocgc (len, FlagNoPointers, 1, 0);
  55   __builtin_memcpy (retdata, buf, len);
  56   ret.__data = retdata;
  57   ret.__length = len;
  58
  59   return ret;
  60 }