blob: 4d5337b2f08b3d8620fbd249e34ff0e98e7310a2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
//
// Copyright(C) 2005-2014 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "txt_utf8.h"
// Encode a Unicode character as UTF-8, storing it in the buffer 'p'
// and returning the new, incremented position.
char *TXT_EncodeUTF8(char *p, unsigned int c)
{
if (c < 0x80) // 1 character (ASCII):
{
p[0] = c;
return p + 1;
}
else if (c < 0x800) // 2 character:
{
p[0] = 0xc0 | (c >> 6);
p[1] = 0x80 | (c & 0x3f);
return p + 2;
}
else if (c < 0x10000) // 3 chacater:
{
p[0] = 0xe0 | (c >> 12);
p[1] = 0x80 | ((c >> 6) & 0x3f);
p[2] = 0x80 | (c & 0x3f);
return p + 3;
}
else if (c < 0x200000) // 4 character:
{
p[0] = 0xf0 | (c >> 18);
p[1] = 0x80 | ((c >> 12) & 0x3f);
p[2] = 0x80 | ((c >> 6) & 0x3f);
p[3] = 0x80 | (c & 0x3f);
return p + 4;
}
else
{
// Too big!
return p;
}
}
// Decode UTF-8 character, incrementing *ptr over the decoded bytes.
unsigned int TXT_DecodeUTF8(const char **ptr)
{
const char *p = *ptr;
unsigned int c;
// UTF-8 decode.
if ((*p & 0x80) == 0) // 1 character (ASCII):
{
c = *p;
*ptr += 1;
}
else if ((p[0] & 0xe0) == 0xc0 // 2 character:
&& (p[1] & 0xc0) == 0x80)
{
c = ((p[0] & 0x1f) << 6)
| (p[1] & 0x3f);
*ptr += 2;
}
else if ((p[0] & 0xf0) == 0xe0 // 3 character:
&& (p[1] & 0xc0) == 0x80
&& (p[2] & 0xc0) == 0x80)
{
c = ((p[0] & 0x0f) << 12)
| ((p[1] & 0x3f) << 6)
| (p[2] & 0x3f);
*ptr += 3;
}
else if ((p[0] & 0xf8) == 0xf0 // 4 character:
&& (p[1] & 0xc0) == 0x80
&& (p[2] & 0xc0) == 0x80
&& (p[3] & 0xc0) == 0x80)
{
c = ((p[0] & 0x07) << 18)
| ((p[1] & 0x3f) << 12)
| ((p[2] & 0x3f) << 6)
| (p[3] & 0x3f);
*ptr += 4;
}
else
{
// Decode failure.
// Don't bother with 5/6 byte sequences.
c = 0;
}
return c;
}
// Count the number of characters in a UTF-8 string.
unsigned int TXT_UTF8_Strlen(const char *s)
{
const char *p;
unsigned int result = 0;
unsigned int c;
for (p = s; *p != '\0';)
{
c = TXT_DecodeUTF8(&p);
if (c == 0)
{
break;
}
++result;
}
return result;
}
// Skip past the first n characters in a UTF-8 string.
char *TXT_UTF8_SkipChars(const char *s, unsigned int n)
{
unsigned int i;
const char *p;
p = s;
for (i = 0; i < n; ++i)
{
if (TXT_DecodeUTF8(&p) == 0)
{
break;
}
}
return (char *) p;
}
|
