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 "runtime.h"
   9 #include "arch.h"
  10 #include "malloc.h"
  11
  12 String
  13 __go_int_array_to_string (const void* p, intgo len)
  14 {
  15   const int32 *ints;
  16   intgo slen;
  17   intgo i;
  18   unsigned char *retdata;
  19   String ret;
  20   unsigned char *s;
  21
  22   ints = (const int32 *) p;
  23
  24   slen = 0;
  25   for (i = 0; i < len; ++i)
  26     {
  27       int32 v;
  28
  29       v = ints[i];
  30
  31       if (v < 0 || v > 0x10ffff)
  32         v = 0xfffd;
  33       else if (0xd800 <= v && v <= 0xdfff)
  34         v = 0xfffd;
  35
  36       if (v <= 0x7f)
  37         slen += 1;
  38       else if (v <= 0x7ff)
  39         slen += 2;
  40       else if (v <= 0xffff)
  41         slen += 3;
  42       else
  43         slen += 4;
  44     }
  45
  46   retdata = runtime_mallocgc ((uintptr) slen, 0, FlagNoScan);
  47   ret.str = retdata;
  48   ret.len = slen;
  49
  50   s = retdata;
  51   for (i = 0; i < len; ++i)
  52     {
  53       int32 v;
  54
  55       v = ints[i];
  56
  57       /* If V is out of range for UTF-8, substitute the replacement
  58          character.  */
  59       if (v < 0 || v > 0x10ffff)
  60         v = 0xfffd;
  61       else if (0xd800 <= v && v <= 0xdfff)
  62         v = 0xfffd;
  63
  64       if (v <= 0x7f)
  65         *s++ = v;
  66       else if (v <= 0x7ff)
  67         {
  68           *s++ = 0xc0 | ((v >> 6) & 0x1f);
  69           *s++ = 0x80 | (v & 0x3f);
  70         }
  71       else if (v <= 0xffff)
  72         {
  73           *s++ = 0xe0 | ((v >> 12) & 0xf);
  74           *s++ = 0x80 | ((v >> 6) & 0x3f);
  75           *s++ = 0x80 | (v & 0x3f);
  76         }
  77       else
  78         {
  79           *s++ = 0xf0 | ((v >> 18) & 0x7);
  80           *s++ = 0x80 | ((v >> 12) & 0x3f);
  81           *s++ = 0x80 | ((v >> 6) & 0x3f);
  82           *s++ = 0x80 | (v & 0x3f);
  83         }
  84     }
  85
  86   __go_assert (s - retdata == slen);
  87
  88   return ret;
  89 }