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

   1 /* go-int-array-to-string.c -- convert an array of ints 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-assert.h"
   8 #include "go-string.h"
   9 #include "runtime.h"
  10 #include "arch.h"
  11 #include "malloc.h"
  12
  13 struct __go_string
  14 __go_int_array_to_string (const void* p, int len)
  15 {
  16   const int *ints;
  17   int slen;
  18   int i;
  19   unsigned char *retdata;
  20   struct __go_string ret;
  21   unsigned char *s;
  22
  23   ints = (const int *) p;
  24
  25   slen = 0;
  26   for (i = 0; i < len; ++i)
  27     {
  28       int v;
  29
  30       v = ints[i];
  31
  32       if (v > 0x10ffff)
  33         v = 0xfffd;
  34
  35       if (v <= 0x7f)
  36         slen += 1;
  37       else if (v <= 0x7ff)
  38         slen += 2;
  39       else if (v <= 0xffff)
  40         slen += 3;
  41       else
  42         slen += 4;
  43     }
  44
  45   retdata = runtime_mallocgc (slen, FlagNoPointers, 1, 0);
  46   ret.__data = retdata;
  47   ret.__length = slen;
  48
  49   s = retdata;
  50   for (i = 0; i < len; ++i)
  51     {
  52       int v;
  53
  54       v = ints[i];
  55
  56       /* If V is out of range for UTF-8, substitute the replacement
  57          character.  */
  58       if (v > 0x10ffff)
  59         v = 0xfffd;
  60
  61       if (v <= 0x7f)
  62         *s++ = v;
  63       else if (v <= 0x7ff)
  64         {
  65           *s++ = 0xc0 | ((v >> 6) & 0x1f);
  66           *s++ = 0x80 | (v & 0x3f);
  67         }
  68       else if (v <= 0xffff)
  69         {
  70           *s++ = 0xe0 | ((v >> 12) & 0xf);
  71           *s++ = 0x80 | ((v >> 6) & 0x3f);
  72           *s++ = 0x80 | (v & 0x3f);
  73         }
  74       else
  75         {
  76           *s++ = 0xf0 | ((v >> 18) & 0x7);
  77           *s++ = 0x80 | ((v >> 12) & 0x3f);
  78           *s++ = 0x80 | ((v >> 6) & 0x3f);
  79           *s++ = 0x80 | (v & 0x3f);
  80         }
  81     }
  82
  83   __go_assert (s - retdata == slen);
  84
  85   return ret;
  86 }