tmbwc.c - plan9port - [fork] Plan 9 from user space
HTML git clone git://src.adamsgaard.dk/plan9port
DIR Log
DIR Files
DIR Refs
DIR README
DIR LICENSE
---
tmbwc.c (2253B)
---
1 #include <stdlib.h>
2
3 /*
4 * Use the FSS-UTF transformation proposed by posix.
5 * We define 7 byte types:
6 * T0 0xxxxxxx 7 free bits
7 * Tx 10xxxxxx 6 free bits
8 * T1 110xxxxx 5 free bits
9 * T2 1110xxxx 4 free bits
10 *
11 * Encoding is as follows.
12 * From hex Thru hex Sequence Bits
13 * 00000000 0000007F T0 7
14 * 00000080 000007FF T1 Tx 11
15 * 00000800 0000FFFF T2 Tx Tx 16
16 */
17
18 int
19 mblen(const char *s, size_t n)
20 {
21
22 return mbtowc(0, s, n);
23 }
24
25 int
26 mbtowc(wchar_t *pwc, const char *s, size_t n)
27 {
28 int c, c1, c2;
29 long l;
30
31 if(!s)
32 return 0;
33
34 if(n < 1)
35 goto bad;
36 c = s[0] & 0xff;
37 if((c & 0x80) == 0x00) {
38 if(pwc)
39 *pwc = c;
40 if(c == 0)
41 return 0;
42 return 1;
43 }
44
45 if(n < 2)
46 goto bad;
47 c1 = (s[1] ^ 0x80) & 0xff;
48 if((c1 & 0xC0) != 0x00)
49 goto bad;
50 if((c & 0xE0) == 0xC0) {
51 l = ((c << 6) | c1) & 0x7FF;
52 if(l < 0x080)
53 goto bad;
54 if(pwc)
55 *pwc = l;
56 return 2;
57 }
58
59 if(n < 3)
60 goto bad;
61 c2 = (s[2] ^ 0x80) & 0xff;
62 if((c2 & 0xC0) != 0x00)
63 goto bad;
64 if((c & 0xF0) == 0xE0) {
65 l = ((((c << 6) | c1) << 6) | c2) & 0xFFFF;
66 if(l < 0x0800)
67 goto bad;
68 if(pwc)
69 *pwc = l;
70 return 3;
71 }
72
73 /*
74 * bad decoding
75 */
76 bad:
77 return -1;
78
79 }
80
81 int
82 wctomb(char *s, wchar_t wchar)
83 {
84 long c;
85
86 if(!s)
87 return 0;
88
89 c = wchar & 0xFFFF;
90 if(c < 0x80) {
91 s[0] = c;
92 return 1;
93 }
94
95 if(c < 0x800) {
96 s[0] = 0xC0 | (c >> 6);
97 s[1] = 0x80 | (c & 0x3F);
98 return 2;
99 }
100
101 s[0] = 0xE0 | (c >> 12);
102 s[1] = 0x80 | ((c >> 6) & 0x3F);
103 s[2] = 0x80 | (c & 0x3F);
104 return 3;
105 }
106
107 size_t
108 mbstowcs(wchar_t *pwcs, const char *s, size_t n)
109 {
110 int i, d, c;
111
112 for(i=0; i < n; i++) {
113 c = *s & 0xff;
114 if(c < 0x80) {
115 *pwcs = c;
116 if(c == 0)
117 break;
118 s++;
119 } else {
120 d = mbtowc(pwcs, s, 3);
121 if(d <= 0)
122 return (size_t)((d<0) ? -1 : i);
123 s += d;
124 }
125 pwcs++;
126 }
127 return i;
128 }
129
130 size_t
131 wcstombs(char *s, const wchar_t *pwcs, size_t n)
132 {
133 int d;
134 long c;
135 char *p, *pe;
136 char buf[3];
137
138 p = s;
139 pe = p+n-3;
140 while(p < pe) {
141 c = *pwcs++;
142 if(c < 0x80)
143 *p++ = c;
144 else
145 p += wctomb(p, c);
146 if(c == 0)
147 return p-s;
148 }
149 while(p < pe+3) {
150 c = *pwcs++;
151 d = wctomb(buf, c);
152 if(p+d <= pe+3) {
153 *p++ = buf[0];
154 if(d > 1) {
155 *p++ = buf[1];
156 if(d > 2)
157 *p++ = buf[2];
158 }
159 }
160 if(c == 0)
161 break;
162 }
163 return p-s;
164 }