FreeBSD/Linux Kernel Cross Reference
sys/fs/unicode.h
1 /* $NetBSD: unicode.h,v 1.2 2004/12/27 18:14:36 jdolecek Exp $ */
2
3 /*-
4 * Copyright (c) 2001, 2004 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the NetBSD
18 * Foundation, Inc. and its contributors.
19 * 4. Neither the name of The NetBSD Foundation nor the names of its
20 * contributors may be used to endorse or promote products derived
21 * from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 /*
37 * Routines for handling Unicode encoded in UTF-8 form, code derived from
38 * src/lib/libc/locale/utf2.c.
39 */
40
41 /*
42 * Read one UTF8-encoded character off the string, shift the string pointer
43 * and return the character.
44 */
45 static u_int16_t
46 wget_utf8(const char **str, size_t *sz)
47 {
48 int c;
49 u_int16_t rune = 0;
50 const char *s = *str;
51 static const int _utf_count[16] = {
52 1, 1, 1, 1, 1, 1, 1, 1,
53 0, 0, 0, 0, 2, 2, 3, 0,
54 };
55
56 /* must be called with at least one byte remaining */
57 KASSERT(*sz > 0);
58
59 c = _utf_count[(s[0] & 0xf0) >> 4];
60 if (c == 0 || c > *sz) {
61 decoding_error:
62 /*
63 * The first character is in range 128-255 and doesn't
64 * mark valid a valid UTF-8 sequence. There is not much
65 * we can do with this, so handle by returning
66 * the first character as if it would be a correctly
67 * encoded ISO-8859-1 character.
68 */
69 c = 1;
70 }
71
72 switch (c) {
73 case 1:
74 rune = s[0] & 0xff;
75 break;
76 case 2:
77 if ((s[1] & 0xc0) != 0x80)
78 goto decoding_error;
79 rune = ((s[0] & 0x1F) << 6) | (s[1] & 0x3F);
80 break;
81 case 3:
82 if ((s[1] & 0xC0) != 0x80 || (s[2] & 0xC0) != 0x80)
83 goto decoding_error;
84 rune = ((s[0] & 0x1F) << 12) | ((s[1] & 0x3F) << 6)
85 | (s[2] & 0x3F);
86 break;
87 }
88
89 *str += c;
90 *sz -= c;
91 return rune;
92 }
93
94 /*
95 * Encode wide character and write it to the string. 'n' specifies
96 * how much buffer space remains in 's'. Returns number of bytes written
97 * to the target string 's'.
98 */
99 static int
100 wput_utf8(char *s, size_t n, u_int16_t wc)
101 {
102 if (wc & 0xf800) {
103 if (n < 3) {
104 /* bound check failure */
105 return 0;
106 }
107
108 s[0] = 0xE0 | ((wc >> 12) & 0x0F);
109 s[1] = 0x80 | ((wc >> 6) & 0x3F);
110 s[2] = 0x80 | ((wc) & 0x3F);
111 return 3;
112 } else if (wc & 0x0780) {
113 if (n < 2) {
114 /* bound check failure */
115 return 0;
116 }
117
118 s[0] = 0xC0 | ((wc >> 6) & 0x1F);
119 s[1] = 0x80 | ((wc) & 0x3F);
120 return 2;
121 } else {
122 if (n < 1) {
123 /* bound check failure */
124 return 0;
125 }
126
127 s[0] = wc;
128 return 1;
129 }
130 }
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