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 #include "gettextP.h"
59
60 #ifndef DIRECTORY_SEPARATOR
61 # define DIRECTORY_SEPARATOR '/'
62 #endif
63
64 #ifndef ISSLASH
65 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
66 #endif
67
68 /* The following static variable is declared 'volatile' to avoid a
69 possible multithread problem in the function get_charset_aliases. If we
70 are running in a threaded environment, and if two threads initialize
71 'charset_aliases' simultaneously, both will produce the same value,
72 and everything will be ok if the two assignments to 'charset_aliases'
73 are atomic. But I don't know what will happen if the two assignments mix. */
74 #if __STDC__ != 1
75 # define volatile /* empty */
76 #endif
77 /* Pointer to the contents of the charset.alias file, if it has already been
78 read, else NULL. Its format is:
79 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
80 static const char * volatile charset_aliases;
81
82 /* GCC LOCAL: Static function prototypes. */
83 static const char *get_charset_aliases PARAMS ((void));
84
85 /* Return a pointer to the contents of the charset.alias file. */
86 static const char *
get_charset_aliases()87 get_charset_aliases ()
88 {
89 const char *cp;
90
91 cp = charset_aliases;
92 if (cp == NULL)
93 {
94 #ifndef WIN32
95 FILE *fp;
96 const char *dir = LIBDIR;
97 const char *base = "charset.alias";
98 char *file_name;
99
100 /* Concatenate dir and base into freshly allocated file_name. */
101 {
102 size_t dir_len = strlen (dir);
103 size_t base_len = strlen (base);
104 int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
105 file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
106 if (file_name != NULL)
107 {
108 memcpy (file_name, dir, dir_len);
109 if (add_slash)
110 file_name[dir_len] = DIRECTORY_SEPARATOR;
111 memcpy (file_name + dir_len + add_slash, base, base_len + 1);
112 }
113 }
114
115 if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
116 /* Out of memory or file not found, treat it as empty. */
117 cp = "";
118 else
119 {
120 /* Parse the file's contents. */
121 int c;
122 char buf1[50+1];
123 char buf2[50+1];
124 char *res_ptr = NULL;
125 size_t res_size = 0;
126 size_t l1, l2;
127
128 for (;;)
129 {
130 c = getc (fp);
131 if (c == EOF)
132 break;
133 if (c == '\n' || c == ' ' || c == '\t')
134 continue;
135 if (c == '#')
136 {
137 /* Skip comment, to end of line. */
138 do
139 c = getc (fp);
140 while (!(c == EOF || c == '\n'));
141 if (c == EOF)
142 break;
143 continue;
144 }
145 ungetc (c, fp);
146 if (fscanf(fp, "%50s %50s", buf1, buf2) < 2)
147 break;
148 l1 = strlen (buf1);
149 l2 = strlen (buf2);
150 if (res_size == 0)
151 {
152 res_size = l1 + 1 + l2 + 1;
153 res_ptr = malloc (res_size + 1);
154 }
155 else
156 {
157 res_size += l1 + 1 + l2 + 1;
158 res_ptr = realloc (res_ptr, res_size + 1);
159 }
160 if (res_ptr == NULL)
161 {
162 /* Out of memory. */
163 res_size = 0;
164 break;
165 }
166 strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
167 strcpy (res_ptr + res_size - (l2 + 1), buf2);
168 }
169 fclose (fp);
170 if (res_size == 0)
171 cp = "";
172 else
173 {
174 *(res_ptr + res_size) = '\0';
175 cp = res_ptr;
176 }
177 }
178
179 if (file_name != NULL)
180 free (file_name);
181
182 #else /* WIN32 */
183
184 /* To avoid the troubles of installing a separate file in the same
185 directory as the DLL and of retrieving the DLL's directory at
186 runtime, simply inline the aliases here. */
187
188 cp = "CP936" "\0" "GBK" "\0"
189 "CP1361" "\0" "JOHAB" "\0";
190 #endif
191
192 charset_aliases = cp;
193 }
194
195 return cp;
196 }
197
198 /* Determine the current locale's character encoding, and canonicalize it
199 into one of the canonical names listed in config.charset.
200 The result must not be freed; it is statically allocated.
201 If the canonical name cannot be determined, the result is a non-canonical
202 name.
203 GCC LOCAL: Get rid of STATIC nonsense. */
204
205 const char *
locale_charset()206 locale_charset ()
207 {
208 const char *codeset;
209 const char *aliases;
210
211 #ifndef WIN32
212
213 # if HAVE_LANGINFO_CODESET
214
215 /* Most systems support nl_langinfo (CODESET) nowadays. */
216 codeset = nl_langinfo (CODESET);
217
218 # else
219
220 /* On old systems which lack it, use setlocale or getenv. */
221 const char *locale = NULL;
222
223 /* But most old systems don't have a complete set of locales. Some
224 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
225 use setlocale here; it would return "C" when it doesn't support the
226 locale name the user has set. */
227 # if HAVE_SETLOCALE && 0
228 locale = setlocale (LC_CTYPE, NULL);
229 # endif
230 if (locale == NULL || locale[0] == '\0')
231 {
232 locale = getenv ("LC_ALL");
233 if (locale == NULL || locale[0] == '\0')
234 {
235 locale = getenv ("LC_CTYPE");
236 if (locale == NULL || locale[0] == '\0')
237 locale = getenv ("LANG");
238 }
239 }
240
241 /* On some old systems, one used to set locale = "iso8859_1". On others,
242 you set it to "language_COUNTRY.charset". In any case, we resolve it
243 through the charset.alias file. */
244 codeset = locale;
245
246 # endif
247
248 #else /* WIN32 */
249
250 static char buf[2 + 10 + 1];
251
252 /* Win32 has a function returning the locale's codepage as a number. */
253 sprintf (buf, "CP%u", GetACP ());
254 codeset = buf;
255
256 #endif
257
258 if (codeset == NULL)
259 /* The canonical name cannot be determined. */
260 codeset = "";
261
262 /* Resolve alias. */
263 for (aliases = get_charset_aliases ();
264 *aliases != '\0';
265 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
266 if (strcmp (codeset, aliases) == 0
267 || (aliases[0] == '*' && aliases[1] == '\0'))
268 {
269 codeset = aliases + strlen (aliases) + 1;
270 break;
271 }
272
273 return codeset;
274 }
275