2 * This file is part of DisOrder.
3 * Copyright (C) 2004, 2005 Richard Kettlewell
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
20 /** @file lib/charset.c @brief Character set conversion */
33 #include "configuration.h"
38 /** @brief Low-level converstion routine
39 * @param from Source encoding
40 * @param to Destination encoding
41 * @param ptr First byte to convert
42 * @param n Number of bytes to convert
43 * @return Converted text, 0-terminated; or NULL on error.
45 static void *convert(const char *from, const char *to,
46 const void *ptr, size_t n) {
49 char *buf = 0, *s, *d;
50 size_t bufsize = 0, sl, dl;
52 if((i = iconv_open(to, from)) == (iconv_t)-1)
53 fatal(errno, "error calling iconv_open");
55 bufsize = bufsize ? 2 * bufsize : 32;
56 buf = xrealloc_noptr(buf, bufsize);
62 /* (void *) to work around FreeBSD's nonstandard iconv prototype */
63 len = iconv(i, (void *)&s, &sl, &d, &dl);
64 } while(len == (size_t)-1 && errno == E2BIG);
66 if(len == (size_t)-1) {
67 error(errno, "error converting from %s to %s", from, to);
73 /** @brief Convert UTF-8 to UCS-4
74 * @param mb Pointer to 0-terminated UTF-8 string
75 * @return Pointer to 0-terminated UCS-4 string
77 * Not everybody's iconv supports UCS-4, and it's inconvenient to have to know
78 * our endianness, and it's easy to convert it ourselves, so we do. See also
81 uint32_t *utf82ucs4(const char *mb) {
88 error(0, "invalid UTF-8 sequence"); return 0;);
89 dynstr_ucs4_append(&d, c);
91 dynstr_ucs4_terminate(&d);
95 /** @brief Convert one UCS-4 character to UTF-8
96 * @param c Character to convert
97 * @param d Dynamic string to append UTF-8 sequence to
98 * @return 0 on success, -1 on error
100 int one_ucs42utf8(uint32_t c, struct dynstr *d) {
104 dynstr_append(d, 0xC0 | (c >> 6));
105 dynstr_append(d, 0x80 | (c & 0x3F));
106 } else if(c < 0x10000) {
107 dynstr_append(d, 0xE0 | (c >> 12));
108 dynstr_append(d, 0x80 | ((c >> 6) & 0x3F));
109 dynstr_append(d, 0x80 | (c & 0x3F));
110 } else if(c < 0x110000) {
111 dynstr_append(d, 0xF0 | (c >> 18));
112 dynstr_append(d, 0x80 | ((c >> 12) & 0x3F));
113 dynstr_append(d, 0x80 | ((c >> 6) & 0x3F));
114 dynstr_append(d, 0x80 | (c & 0x3F));
116 error(0, "invalid UCS-4 character %#"PRIx32, c);
122 /** @brief Convert UCS-4 to UTF-8
123 * @param u Pointer to 0-terminated UCS-4 string
124 * @return Pointer to 0-terminated UTF-8 string
126 * See @ref utf82ucs4().
128 char *ucs42utf8(const uint32_t *u) {
134 if(one_ucs42utf8(c, &d))
137 dynstr_terminate(&d);
141 /** @brief Convert from the local multibyte encoding to UTF-8 */
142 char *mb2utf8(const char *mb) {
143 return convert(nl_langinfo(CODESET), "UTF-8", mb, strlen(mb) + 1);
146 /** @brief Convert from UTF-8 to the local multibyte encoding */
147 char *utf82mb(const char *utf8) {
148 return convert("UTF-8", nl_langinfo(CODESET), utf8, strlen(utf8) + 1);
151 /** @brief Convert from encoding @p from to UTF-8 */
152 char *any2utf8(const char *from, const char *any) {
153 return convert(from, "UTF-8", any, strlen(any) + 1);
156 /** @brief Convert from encoding @p from to the local multibyte encoding */
157 char *any2mb(const char *from, const char *any) {
158 if(from) return convert(from, nl_langinfo(CODESET), any, strlen(any) + 1);
159 else return xstrdup(any);
162 /** @brief Convert from encoding @p from to encoding @p to */
163 char *any2any(const char *from,
166 if(from || to) return convert(from, to, any, strlen(any) + 1);
167 else return xstrdup(any);
170 /** @brief strlen workalike for UCS-4 strings
172 * We don't rely on the local @c wchar_t being UCS-4.
174 int ucs4cmp(const uint32_t *a, const uint32_t *b) {
175 while(*a && *b && *a == *b) ++a, ++b;
176 if(*a > *b) return 1;
177 else if(*a < *b) return -1;
181 /** @brief Return nonzero if @p c is a combining character */
182 static int combining(int c) {
183 if(c < UNICODE_NCHARS) {
184 const struct unidata *const ud = &unidata[c / 256][c % 256];
186 return ud->gc == unicode_gc_Mn || ud->ccc != 0;
188 /* Assume unknown characters are noncombining */
192 /** @brief Truncate a string for display purposes
193 * @param s Pointer to UTF-8 string
194 * @param max Maximum number of columns
195 * @return @p or truncated string (never NULL)
197 * We don't correctly support bidi or double-width characters yet, nor
198 * locate default grapheme cluster boundaries for saner truncation.
200 const char *truncate_for_display(const char *s, long max) {
201 const char *t = s, *r, *cut = 0;
206 /* We need to discover two things: firstly whether the string is
207 * longer than @p max glyphs and secondly if it is not, where to cut
210 * Combining characters follow their base character (unicode
211 * standard 5.0 s2.11), so after each base character we must
214 PARSE_UTF8(t, c, return s);
216 /* This must be an initial combining character. We just skip it. */
218 /* So c must be a base character. It may be followed by any
219 * number of combining characters. We advance past them. */
222 PARSE_UTF8(t, c, return s);
223 } while(combining(c));
224 /* Last character wasn't a combining character so back up */
227 /* So now there are N glyphs before position T. We might
228 * therefore have reached the cut position. */
232 /* If the string is short enough we return it unmodified */
235 truncated = xmalloc_noptr(cut - s + 4);
236 memcpy(truncated, s, cut - s);
237 strcpy(truncated + (cut - s), "...");