chiark / gitweb /
truncate_for_display() now uses unicode.c grapheme boundary deetection
[disorder] / lib / charset.c
CommitLineData
460b9539 1/*
2 * This file is part of DisOrder.
3 * Copyright (C) 2004, 2005 Richard Kettlewell
4 *
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.
9 *
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.
14 *
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
18 * USA
19 */
14ad73b9 20/** @file lib/charset.c @brief Character set conversion */
460b9539 21
22#include <config.h>
23#include "types.h"
24
25#include <iconv.h>
26#include <string.h>
27#include <errno.h>
28#include <langinfo.h>
29
30#include "mem.h"
31#include "log.h"
32#include "charset.h"
33#include "configuration.h"
460b9539 34#include "vector.h"
11f598d1 35#include "unicode.h"
460b9539 36
14ad73b9
RK
37/** @brief Low-level converstion routine
38 * @param from Source encoding
39 * @param to Destination encoding
40 * @param ptr First byte to convert
41 * @param n Number of bytes to convert
42 * @return Converted text, 0-terminated; or NULL on error.
43 */
460b9539 44static void *convert(const char *from, const char *to,
45 const void *ptr, size_t n) {
46 iconv_t i;
47 size_t len;
48 char *buf = 0, *s, *d;
49 size_t bufsize = 0, sl, dl;
50
51 if((i = iconv_open(to, from)) == (iconv_t)-1)
52 fatal(errno, "error calling iconv_open");
53 do {
54 bufsize = bufsize ? 2 * bufsize : 32;
55 buf = xrealloc_noptr(buf, bufsize);
56 iconv(i, 0, 0, 0, 0);
57 s = (char *)ptr;
58 sl = n;
59 d = buf;
60 dl = bufsize;
61 /* (void *) to work around FreeBSD's nonstandard iconv prototype */
62 len = iconv(i, (void *)&s, &sl, &d, &dl);
63 } while(len == (size_t)-1 && errno == E2BIG);
64 iconv_close(i);
65 if(len == (size_t)-1) {
66 error(errno, "error converting from %s to %s", from, to);
67 return 0;
68 }
69 return buf;
70}
71
14ad73b9 72/** @brief Convert from the local multibyte encoding to UTF-8 */
460b9539 73char *mb2utf8(const char *mb) {
74 return convert(nl_langinfo(CODESET), "UTF-8", mb, strlen(mb) + 1);
75}
76
14ad73b9 77/** @brief Convert from UTF-8 to the local multibyte encoding */
460b9539 78char *utf82mb(const char *utf8) {
79 return convert("UTF-8", nl_langinfo(CODESET), utf8, strlen(utf8) + 1);
80}
81
14ad73b9 82/** @brief Convert from encoding @p from to UTF-8 */
460b9539 83char *any2utf8(const char *from, const char *any) {
84 return convert(from, "UTF-8", any, strlen(any) + 1);
85}
86
14ad73b9 87/** @brief Convert from encoding @p from to the local multibyte encoding */
460b9539 88char *any2mb(const char *from, const char *any) {
89 if(from) return convert(from, nl_langinfo(CODESET), any, strlen(any) + 1);
90 else return xstrdup(any);
91}
92
14ad73b9 93/** @brief Convert from encoding @p from to encoding @p to */
460b9539 94char *any2any(const char *from,
95 const char *to,
96 const char *any) {
97 if(from || to) return convert(from, to, any, strlen(any) + 1);
98 else return xstrdup(any);
99}
100
61507e3c
RK
101/** @brief Truncate a string for display purposes
102 * @param s Pointer to UTF-8 string
103 * @param max Maximum number of columns
104 * @return @p or truncated string (never NULL)
105 *
11f598d1
RK
106 * Returns a string that is no longer than @p max graphemes long and is either
107 * (canonically) equal to @p s or is a truncated form of it with an ellipsis
108 * appended.
109 *
110 * We don't take display width into account (tricky for HTML!) and we don't
111 * attempt to implement the Bidi algorithm. If you have track names for which
112 * either of these matter in practice then get in touch.
61507e3c
RK
113 */
114const char *truncate_for_display(const char *s, long max) {
11f598d1
RK
115 uint32_t *s32;
116 size_t l32, cut;
117 utf32_iterator it;
61507e3c 118
11f598d1
RK
119 /* Convert to UTF-32 for processing */
120 if(!(s32 = utf8_to_utf32(s, strlen(s), &l32)))
121 return 0;
122 it = utf32_iterator_new(s32, l32);
123 cut = l32;
124 while(max && utf32_iterator_where(it) < l32) {
125 utf32_iterator_advance(it, 1);
126 if(utf32_iterator_grapheme_boundary(it))
127 --max;
128 if(max == 1)
129 cut = utf32_iterator_where(it);
130 }
131 if(max == 0) { /* we need to cut */
132 s32[cut] = 0x2026; /* HORIZONTAL ELLIPSIS */
133 l32 = cut + 1;
134 s = utf32_to_utf8(s32, l32, 0);
61507e3c 135 }
11f598d1
RK
136 xfree(s32);
137 return s;
61507e3c
RK
138}
139
460b9539 140/*
141Local Variables:
142c-basic-offset:2
143comment-column:40
11f598d1
RK
144fill-column:79
145indent-tabs-mode:nil
460b9539 146End:
147*/