1 /* Determine a canonical name for the current locale's character encoding.
2
3 Copyright (C) 2000-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
18 USA. */
19
20 /* Written by Bruno Haible <bruno@clisp.org>. */
21
22 #include "config.h"
23
24 /* Specification. */
25 #include "localcharset.h"
26
27 #include <stddef.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <stdlib.h>
31
32 #if defined _WIN32 || defined __WIN32__
33 # define WIN32_NATIVE
34 #endif
35
36 #if defined __EMX__
37 /* Assume EMX program runs on OS/2, even if compiled under DOS. */
38 # define OS2
39 #endif
40
41 #if !defined WIN32_NATIVE
42 # if HAVE_LANGINFO_CODESET
43 # include <langinfo.h>
44 # else
45 # if 0 /* see comment below */
46 # include <locale.h>
47 # endif
48 # endif
49 # ifdef __CYGWIN__
50 # define WIN32_LEAN_AND_MEAN
51 # include <windows.h>
52 # endif
53 #elif defined WIN32_NATIVE
54 # define WIN32_LEAN_AND_MEAN
55 # include <windows.h>
56 #endif
57 #if defined OS2
58 # define INCL_DOS
59 # include <os2.h>
60 #endif
61
62 #if ENABLE_RELOCATABLE
63 # include "relocatable.h"
64 #else
65 # define relocate(pathname) (pathname)
66 #endif
67
68 /* Get GLIB_CHARSETALIAS_DIR. */
69 #ifndef GLIB_CHARSETALIAS_DIR
70 # define GLIB_CHARSETALIAS_DIR LIBDIR
71 #endif
72
73 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
74 /* Win32, Cygwin, OS/2, DOS */
75 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
76 #endif
77
78 #ifndef DIRECTORY_SEPARATOR
79 # define DIRECTORY_SEPARATOR '/'
80 #endif
81
82 #ifndef ISSLASH
83 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
84 #endif
85
86 #if HAVE_DECL_GETC_UNLOCKED
87 # undef getc
88 # define getc getc_unlocked
89 #endif
90
91 /* The following static variable is declared 'volatile' to avoid a
92 possible multithread problem in the function get_charset_aliases. If we
93 are running in a threaded environment, and if two threads initialize
94 'charset_aliases' simultaneously, both will produce the same value,
95 and everything will be ok if the two assignments to 'charset_aliases'
96 are atomic. But I don't know what will happen if the two assignments mix. */
97 #if __STDC__ != 1
98 # define volatile /* empty */
99 #endif
100 /* Pointer to the contents of the charset.alias file, if it has already been
101 read, else NULL. Its format is:
102 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
103 static const char * volatile charset_aliases;
104
105 /* Return a pointer to the contents of the charset.alias file. */
106 const char *
107 _g_locale_get_charset_aliases (void)
108 {
109 const char *cp;
110
111 cp = charset_aliases;
112 if (cp == NULL)
113 {
114 #if !(defined VMS || defined WIN32_NATIVE || defined __CYGWIN__)
115 FILE *fp;
116 const char *dir;
117 const char *base = "charset.alias";
118 char *file_name;
119
120 dir = relocate (GLIB_CHARSETALIAS_DIR);
121
122 /* Concatenate dir and base into freshly allocated file_name. */
123 {
124 size_t dir_len = strlen (dir);
125 size_t base_len = strlen (base);
126 int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
127 file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
128 if (file_name != NULL)
129 {
130 memcpy (file_name, dir, dir_len);
131 if (add_slash)
132 file_name[dir_len] = DIRECTORY_SEPARATOR;
133 memcpy (file_name + dir_len + add_slash, base, base_len + 1);
134 }
135 }
136
137 if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
138 /* Out of memory or file not found, treat it as empty. */
139 cp = "";
140 else
141 {
142 /* Parse the file's contents. */
143 char *res_ptr = NULL;
144 size_t res_size = 0;
145
146 for (;;)
147 {
148 int c;
149 char buf1[50+1];
150 char buf2[50+1];
151 size_t l1, l2;
152 char *old_res_ptr;
153
154 c = getc (fp);
155 if (c == EOF)
156 break;
157 if (c == '\n' || c == ' ' || c == '\t')
158 continue;
159 if (c == '#')
160 {
161 /* Skip comment, to end of line. */
162 do
163 c = getc (fp);
164 while (!(c == EOF || c == '\n'));
165 if (c == EOF)
166 break;
167 continue;
168 }
169 ungetc (c, fp);
170 if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
171 break;
172 l1 = strlen (buf1);
173 l2 = strlen (buf2);
174 old_res_ptr = res_ptr;
175 if (res_size == 0)
176 {
177 res_size = l1 + 1 + l2 + 1;
178 res_ptr = (char *) malloc (res_size + 1);
179 }
180 else
181 {
182 res_size += l1 + 1 + l2 + 1;
183 res_ptr = (char *) realloc (res_ptr, res_size + 1);
184 }
185 if (res_ptr == NULL)
186 {
187 /* Out of memory. */
188 res_size = 0;
189 if (old_res_ptr != NULL)
190 free (old_res_ptr);
191 break;
192 }
193 strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
194 strcpy (res_ptr + res_size - (l2 + 1), buf2);
195 }
196 fclose (fp);
197 if (res_size == 0)
198 cp = "";
199 else
200 {
201 *(res_ptr + res_size) = '\0';
202 cp = res_ptr;
203 }
204 }
205
206 if (file_name != NULL)
207 free (file_name);
208
209 #else
210
211 # if defined VMS
212 /* To avoid the troubles of an extra file charset.alias_vms in the
213 sources of many GNU packages, simply inline the aliases here. */
214 /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
215 "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
216 section 10.7 "Handling Different Character Sets". */
217 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
218 "ISO8859-2" "\0" "ISO-8859-2" "\0"
219 "ISO8859-5" "\0" "ISO-8859-5" "\0"
220 "ISO8859-7" "\0" "ISO-8859-7" "\0"
221 "ISO8859-8" "\0" "ISO-8859-8" "\0"
222 "ISO8859-9" "\0" "ISO-8859-9" "\0"
223 /* Japanese */
224 "eucJP" "\0" "EUC-JP" "\0"
225 "SJIS" "\0" "SHIFT_JIS" "\0"
226 "DECKANJI" "\0" "DEC-KANJI" "\0"
227 "SDECKANJI" "\0" "EUC-JP" "\0"
228 /* Chinese */
229 "eucTW" "\0" "EUC-TW" "\0"
230 "DECHANYU" "\0" "DEC-HANYU" "\0"
231 "DECHANZI" "\0" "GB2312" "\0"
232 /* Korean */
233 "DECKOREAN" "\0" "EUC-KR" "\0";
234 # endif
235
236 # if defined WIN32_NATIVE || defined __CYGWIN__
237 /* To avoid the troubles of installing a separate file in the same
238 directory as the DLL and of retrieving the DLL's directory at
239 runtime, simply inline the aliases here. */
240
241 cp = "CP936" "\0" "GBK" "\0"
242 "CP1361" "\0" "JOHAB" "\0"
243 "CP20127" "\0" "ASCII" "\0"
244 "CP20866" "\0" "KOI8-R" "\0"
245 "CP20936" "\0" "GB2312" "\0"
246 "CP21866" "\0" "KOI8-RU" "\0"
247 "CP28591" "\0" "ISO-8859-1" "\0"
248 "CP28592" "\0" "ISO-8859-2" "\0"
249 "CP28593" "\0" "ISO-8859-3" "\0"
250 "CP28594" "\0" "ISO-8859-4" "\0"
251 "CP28595" "\0" "ISO-8859-5" "\0"
252 "CP28596" "\0" "ISO-8859-6" "\0"
253 "CP28597" "\0" "ISO-8859-7" "\0"
254 "CP28598" "\0" "ISO-8859-8" "\0"
255 "CP28599" "\0" "ISO-8859-9" "\0"
256 "CP28605" "\0" "ISO-8859-15" "\0"
257 "CP38598" "\0" "ISO-8859-8" "\0"
258 "CP51932" "\0" "EUC-JP" "\0"
259 "CP51936" "\0" "GB2312" "\0"
260 "CP51949" "\0" "EUC-KR" "\0"
261 "CP51950" "\0" "EUC-TW" "\0"
262 "CP54936" "\0" "GB18030" "\0"
263 "CP65001" "\0" "UTF-8" "\0";
264 # endif
265 #endif
266
267 charset_aliases = cp;
268 }
269
270 return cp;
271 }
272
273 /* Determine the current locale's character encoding, and canonicalize it
274 into one of the canonical names listed in config.charset.
275 The result must not be freed; it is statically allocated.
276 If the canonical name cannot be determined, the result is a non-canonical
277 name. */
278
279 const char *
280 _g_locale_charset_raw (void)
281 {
282 const char *codeset;
283
284 #if !(defined WIN32_NATIVE || defined OS2)
285
286 # if HAVE_LANGINFO_CODESET
287
288 /* Most systems support nl_langinfo (CODESET) nowadays. */
289 codeset = nl_langinfo (CODESET);
290
291 # ifdef __CYGWIN__
292 /* Cygwin 2006 does not have locales. nl_langinfo (CODESET) always
293 returns "US-ASCII". As long as this is not fixed, return the suffix
294 of the locale name from the environment variables (if present) or
295 the codepage as a number. */
296 if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
297 {
298 const char *locale;
299 static char buf[2 + 10 + 1];
300
301 locale = getenv ("LC_ALL");
302 if (locale == NULL || locale[0] == '\0')
303 {
304 locale = getenv ("LC_CTYPE");
305 if (locale == NULL || locale[0] == '\0')
306 locale = getenv ("LANG");
307 }
308 if (locale != NULL && locale[0] != '\0')
309 {
310 /* If the locale name contains an encoding after the dot, return
311 it. */
312 const char *dot = strchr (locale, '.');
313
314 if (dot != NULL)
315 {
316 const char *modifier;
317
318 dot++;
319 /* Look for the possible @... trailer and remove it, if any. */
320 modifier = strchr (dot, '@');
321 if (modifier == NULL)
322 return dot;
323 if (modifier - dot < sizeof (buf))
324 {
325 memcpy (buf, dot, modifier - dot);
326 buf [modifier - dot] = '\0';
327 return buf;
328 }
329 }
330 }
331
332 /* Woe32 has a function returning the locale's codepage as a number. */
333 sprintf (buf, "CP%u", GetACP ());
334 codeset = buf;
335 }
336 # endif
337
338 # else
339
340 /* On old systems which lack it, use setlocale or getenv. */
341 const char *locale = NULL;
342
343 /* But most old systems don't have a complete set of locales. Some
344 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
345 use setlocale here; it would return "C" when it doesn't support the
346 locale name the user has set. */
347 # if 0
348 locale = setlocale (LC_CTYPE, NULL);
349 # endif
350 if (locale == NULL || locale[0] == '\0')
351 {
352 locale = getenv ("LC_ALL");
353 if (locale == NULL || locale[0] == '\0')
354 {
355 locale = getenv ("LC_CTYPE");
356 if (locale == NULL || locale[0] == '\0')
357 locale = getenv ("LANG");
358 }
359 }
360
361 /* On some old systems, one used to set locale = "iso8859_1". On others,
362 you set it to "language_COUNTRY.charset". In any case, we resolve it
363 through the charset.alias file. */
364 codeset = locale;
365
366 # endif
367
368 #elif defined WIN32_NATIVE
369
370 static char buf[2 + 10 + 1];
371
372 /* Woe32 has a function returning the locale's codepage as a number. */
373 sprintf (buf, "CP%u", GetACP ());
374 codeset = buf;
375
376 #elif defined OS2
377
378 const char *locale;
379 static char buf[2 + 10 + 1];
380 ULONG cp[3];
381 ULONG cplen;
382
383 /* Allow user to override the codeset, as set in the operating system,
384 with standard language environment variables. */
385 locale = getenv ("LC_ALL");
386 if (locale == NULL || locale[0] == '\0')
387 {
388 locale = getenv ("LC_CTYPE");
389 if (locale == NULL || locale[0] == '\0')
390 locale = getenv ("LANG");
391 }
392 if (locale != NULL && locale[0] != '\0')
393 {
394 /* If the locale name contains an encoding after the dot, return it. */
395 const char *dot = strchr (locale, '.');
396
397 if (dot != NULL)
398 {
399 const char *modifier;
400
401 dot++;
402 /* Look for the possible @... trailer and remove it, if any. */
403 modifier = strchr (dot, '@');
404 if (modifier == NULL)
405 return dot;
406 if (modifier - dot < sizeof (buf))
407 {
408 memcpy (buf, dot, modifier - dot);
409 buf [modifier - dot] = '\0';
410 return buf;
411 }
412 }
413
414 /* Resolve through the charset.alias file. */
415 codeset = locale;
416 }
417 else
418 {
419 /* OS/2 has a function returning the locale's codepage as a number. */
420 if (DosQueryCp (sizeof (cp), cp, &cplen))
421 codeset = "";
422 else
423 {
424 sprintf (buf, "CP%u", cp[0]);
425 codeset = buf;
426 }
427 }
428
429 #endif
430
431 return codeset;
432 }
433
434 const char *
435 _g_locale_charset_unalias (const char *codeset)
436 {
437 const char *aliases;
438
439 if (codeset == NULL)
440 /* The canonical name cannot be determined. */
441 codeset = "";
442
443 /* Resolve alias. */
444 for (aliases = _g_locale_get_charset_aliases ();
445 *aliases != '\0';
446 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
447 if (strcmp (codeset, aliases) == 0
448 || (aliases[0] == '*' && aliases[1] == '\0'))
449 {
450 codeset = aliases + strlen (aliases) + 1;
451 break;
452 }
453
454 /* Don't return an empty string. GNU libc and GNU libiconv interpret
455 the empty string as denoting "the locale's character encoding",
456 thus GNU libiconv would call this function a second time. */
457 if (codeset[0] == '\0')
458 codeset = "ASCII";
459
460 return codeset;
461 }