1 /* Determine a canonical name for the current locale's character encoding.
2
3 Copyright (C) 2000-2001 Free Software Foundation, Inc.
4
5 This program is free software; you can redistribute it and/or modify it
6 under the terms of the GNU Library General Public License as published
7 by the Free Software Foundation; either version 2, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License 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
20 /* Written by Bruno Haible <haible@clisp.cons.org>. */
21
22 #ifdef HAVE_CONFIG_H
23 #include "config.h"
24 #endif
25
26 #if HAVE_STDDEF_H
27 #include <stddef.h>
28 #endif
29
30 #include <stdio.h>
31 #if HAVE_STRING_H
32 #include <string.h>
33 #else
34 #include <strings.h>
35 #endif
36 #if HAVE_STDLIB_H
37 #include <stdlib.h>
38 #endif
39
40 #if defined _WIN32 || defined __WIN32__
41 #undef WIN32 /* avoid warning on mingw32 */
42 #define WIN32
43 #endif
44
45 #ifndef WIN32
46 #if HAVE_LANGINFO_CODESET
47 #include <langinfo.h>
48 #else
49 #if HAVE_SETLOCALE
50 #include <locale.h>
51 #endif
52 #endif
53 #else /* WIN32 */
54 #define WIN32_LEAN_AND_MEAN
55 #include <windows.h>
56 #endif
57
58 #ifndef DIRECTORY_SEPARATOR
59 #define DIRECTORY_SEPARATOR '/'
60 #endif
61
62 #ifndef ISSLASH
63 #define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
64 #endif
65
66 /* The following static variable is declared 'volatile' to avoid a
67 possible multithread problem in the function get_charset_aliases. If we
68 are running in a threaded environment, and if two threads initialize
69 'charset_aliases' simultaneously, both will produce the same value,
70 and everything will be ok if the two assignments to 'charset_aliases'
71 are atomic. But I don't know what will happen if the two assignments mix. */
72 #if __STDC__ != 1
73 #define volatile /* empty */
74 #endif
75 /* Pointer to the contents of the charset.alias file, if it has already been
76 read, else NULL. Its format is:
77 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
78 static const unsigned char *volatile charset_aliases;
79
80 /* Return a pointer to the contents of the charset.alias file. */
81 static const unsigned char *
get_charset_aliases(void)82 get_charset_aliases(void)
83 {
84 const unsigned char *cp;
85
86 cp = charset_aliases;
87 if (cp == NULL) {
88 #ifndef WIN32
89 FILE *fp;
90 const unsigned char *dir = LIBDIR;
91 const unsigned char *base = "charset.alias";
92 unsigned char *file_name;
93
94 /* Concatenate dir and base into freshly allocated file_name. */
95 {
96 size_t dir_len = strlen(dir);
97 size_t base_len = strlen(base);
98 int add_slash = (dir_len > 0
99 && !ISSLASH(dir[dir_len - 1]));
100 file_name =
101 (unsigned char *) malloc(dir_len + add_slash + base_len +
102 1);
103 if (file_name != NULL) {
104 memcpy(file_name, dir, dir_len);
105 if (add_slash)
106 file_name[dir_len] =
107 DIRECTORY_SEPARATOR;
108 memcpy(file_name + dir_len + add_slash, base,
109 base_len + 1);
110 }
111 }
112
113 if (file_name == NULL || (fp = fopen(file_name, "rb")) == NULL)
114 /* Out of memory or file not found, treat it as empty. */
115 cp = "";
116 else {
117 /* Parse the file's contents. */
118 int c;
119 unsigned char buf1[50 + 1];
120 unsigned char buf2[50 + 1];
121 unsigned char *res_ptr = NULL;
122 size_t res_size = 0;
123 size_t l1, l2;
124
125 for (;;) {
126 c = getc(fp);
127 if (c == EOF)
128 break;
129 if (c == '\n' || c == ' ' || c == '\t')
130 continue;
131 if (c == '#') {
132 /* Skip comment, to end of line. */
133 do
134 c = getc(fp);
135 while (!(c == EOF || c == '\n'));
136 if (c == EOF)
137 break;
138 continue;
139 }
140 ungetc(c, fp);
141 if (fscanf(fp, "%50s %50s", buf1, buf2) < 2)
142 break;
143 l1 = strlen(buf1);
144 l2 = strlen(buf2);
145 if (res_size == 0) {
146 res_size = l1 + 1 + l2 + 1;
147 res_ptr = malloc(res_size + 1);
148 } else {
149 res_size += l1 + 1 + l2 + 1;
150 res_ptr =
151 realloc(res_ptr, res_size + 1);
152 }
153 if (res_ptr == NULL) {
154 /* Out of memory. */
155 res_size = 0;
156 break;
157 }
158 strcpy(res_ptr + res_size - (l2 + 1) - (l1 + 1),
159 buf1);
160 strcpy(res_ptr + res_size - (l2 + 1), buf2);
161 }
162 fclose(fp);
163 if (res_size == 0)
164 cp = "";
165 else {
166 *(res_ptr + res_size) = '\0';
167 cp = res_ptr;
168 }
169 }
170
171 if (file_name != NULL)
172 free(file_name);
173
174 #else /* WIN32 */
175
176 /* To avoid the troubles of installing a separate file in the same
177 directory as the DLL and of retrieving the DLL's directory at
178 runtime, simply inline the aliases here. */
179
180 cp = "CP936" "\0" "GBK" "\0" "CP1361" "\0" "JOHAB" "\0";
181 #endif
182
183 charset_aliases = cp;
184 }
185
186 return cp;
187 }
188
189 /* Determine the current locale's character encoding, and canonicalize it
190 into one of the canonical names listed in config.charset.
191 The result must not be freed; it is statically allocated.
192 If the canonical name cannot be determined, the result is a non-canonical
193 name. */
194
195 /* Should be in .h file, used in _nl_init_domain_conv() function. */
196 const unsigned char *locale_charset(void);
197
198 #ifdef STATIC
199 STATIC
200 #endif
201 const unsigned char *
locale_charset(void)202 locale_charset(void)
203 {
204 const unsigned char *codeset;
205 const unsigned char *aliases;
206
207 #ifndef WIN32
208
209 #if HAVE_LANGINFO_CODESET
210
211 /* Most systems support nl_langinfo (CODESET) nowadays. */
212 codeset = nl_langinfo(CODESET);
213
214 #else
215
216 /* On old systems which lack it, use setlocale or getenv. */
217 const unsigned char *locale = NULL;
218
219 /* But most old systems don't have a complete set of locales. Some
220 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
221 use setlocale here; it would return "C" when it doesn't support the
222 locale name the user has set. */
223 #if HAVE_SETLOCALE && 0
224 locale = setlocale(LC_CTYPE, NULL);
225 #endif
226 if (locale == NULL || locale[0] == '\0') {
227 locale = getenv("LC_ALL");
228 if (locale == NULL || locale[0] == '\0') {
229 locale = getenv("LC_CTYPE");
230 if (locale == NULL || locale[0] == '\0')
231 locale = getenv("LANG");
232 }
233 }
234
235 /* On some old systems, one used to set locale = "iso8859_1". On others,
236 you set it to "language_COUNTRY.charset". In any case, we resolve it
237 through the charset.alias file. */
238 codeset = locale;
239
240 #endif
241
242 #else /* WIN32 */
243
244 static unsigned char buf[2 + 10 + 1];
245
246 /* Win32 has a function returning the locale's codepage as a number. */
247 sprintf(buf, "CP%u", GetACP());
248 codeset = buf;
249
250 #endif
251
252 if (codeset == NULL)
253 /* The canonical name cannot be determined. */
254 codeset = "";
255
256 /* Resolve alias. */
257 for (aliases = get_charset_aliases();
258 *aliases != '\0';
259 aliases += strlen(aliases) + 1, aliases += strlen(aliases) + 1)
260 if (strcmp(codeset, aliases) == 0
261 || (aliases[0] == '*' && aliases[1] == '\0')) {
262 codeset = aliases + strlen(aliases) + 1;
263 break;
264 }
265
266 return codeset;
267 }
268