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
__go_int_array_to_string(const void * p,intgo len)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 }
90