xref: /netbsd-src/sys/fs/unicode.h (revision fad4c9f71477ae11cea2ee75ec82151ac770a534)
1 /* $NetBSD: unicode.h,v 1.4 2006/05/20 08:28:27 yamt 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  * Copyright (c) 1993
38  *	The Regents of the University of California.  All rights reserved.
39  *
40  * This code is derived from software contributed to Berkeley by
41  * Paul Borman at Krystal Technologies.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  */
71 
72 /*
73  * Routines for handling Unicode encoded in UTF-8 form, code derived from
74  * src/lib/libc/locale/utf2.c.
75  */
76 
77 /*
78  * Read one UTF8-encoded character off the string, shift the string pointer
79  * and return the character.
80  */
81 static u_int16_t
82 wget_utf8(const char **str, size_t *sz)
83 {
84 	int c;
85 	u_int16_t rune = 0;
86 	const char *s = *str;
87 	static const int _utf_count[16] = {
88 		1, 1, 1, 1, 1, 1, 1, 1,
89 		0, 0, 0, 0, 2, 2, 3, 0,
90 	};
91 
92 	/* must be called with at least one byte remaining */
93 	KASSERT(*sz > 0);
94 
95 	c = _utf_count[(s[0] & 0xf0) >> 4];
96 	if (c == 0 || c > *sz) {
97     decoding_error:
98 		/*
99 		 * The first character is in range 128-255 and doesn't
100 		 * mark valid a valid UTF-8 sequence. There is not much
101 		 * we can do with this, so handle by returning
102 		 * the first character as if it would be a correctly
103 		 * encoded ISO-8859-1 character.
104 		 */
105 		c = 1;
106 	}
107 
108 	switch (c) {
109 	case 1:
110 		rune = s[0] & 0xff;
111 		break;
112 	case 2:
113 		if ((s[1] & 0xc0) != 0x80)
114 			goto decoding_error;
115 		rune = ((s[0] & 0x1F) << 6) | (s[1] & 0x3F);
116 		break;
117 	case 3:
118 		if ((s[1] & 0xC0) != 0x80 || (s[2] & 0xC0) != 0x80)
119 			goto decoding_error;
120 		rune = ((s[0] & 0x1F) << 12) | ((s[1] & 0x3F) << 6)
121 		    | (s[2] & 0x3F);
122 		break;
123 	}
124 
125 	*str += c;
126 	*sz -= c;
127 	return rune;
128 }
129 
130 /*
131  * Encode wide character and write it to the string. 'n' specifies
132  * how much buffer space remains in 's'. Returns number of bytes written
133  * to the target string 's'.
134  */
135 static int
136 wput_utf8(char *s, size_t n, u_int16_t wc)
137 {
138 	if (wc & 0xf800) {
139 		if (n < 3) {
140 			/* bound check failure */
141 			return 0;
142 		}
143 
144 		s[0] = 0xE0 | ((wc >> 12) & 0x0F);
145 		s[1] = 0x80 | ((wc >> 6) & 0x3F);
146 		s[2] = 0x80 | ((wc) & 0x3F);
147 		return 3;
148 	} else if (wc & 0x0780) {
149 		if (n < 2) {
150 			/* bound check failure */
151 			return 0;
152 		}
153 
154 		s[0] = 0xC0 | ((wc >> 6) & 0x1F);
155 		s[1] = 0x80 | ((wc) & 0x3F);
156 		return 2;
157 	} else {
158 		if (n < 1) {
159 			/* bound check failure */
160 			return 0;
161 		}
162 
163 		s[0] = wc;
164 		return 1;
165 	}
166 }
167