source: vendor/tar/1.16.1/lib/localcharset.c@ 3342

Last change on this file since 3342 was 3342, checked in by bird, 18 years ago

tar 1.16.1
File size: 12.2 KB
Line 
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
6 it under the terms of the GNU General Public License as published by
7 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
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18
19/* Written by Bruno Haible <bruno@clisp.org>. */
20
21#include <config.h>
22
23/* Specification. */
24#include "localcharset.h"
25
26#include <stddef.h>
27#include <stdio.h>
28#include <string.h>
29#include <stdlib.h>
30
31#if defined _WIN32 || defined __WIN32__
32# define WIN32_NATIVE
33#endif
34
35#if defined __EMX__
36/* Assume EMX program runs on OS/2, even if compiled under DOS. */
37# define OS2
38#endif
39
40#if !defined WIN32_NATIVE
41# if HAVE_LANGINFO_CODESET
42# include <langinfo.h>
43# else
44# if 0 /* see comment below */
45# include <locale.h>
46# endif
47# endif
48# ifdef __CYGWIN__
49# define WIN32_LEAN_AND_MEAN
50# include <windows.h>
51# endif
52#elif defined WIN32_NATIVE
53# define WIN32_LEAN_AND_MEAN
54# include <windows.h>
55#endif
56#if defined OS2
57# define INCL_DOS
58# include <os2.h>
59#endif
60
61#if ENABLE_RELOCATABLE
62# include "relocatable.h"
63#else
64# define relocate(pathname) (pathname)
65#endif
66
67/* Get LIBDIR. */
68#ifndef LIBDIR
69# include "configmake.h"
70#endif
71
72#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
73 /* Win32, Cygwin, OS/2, DOS */
74# define ISSLASH(C) ((C) == '/' || (C) == '\\')
75#endif
76
77#ifndef DIRECTORY_SEPARATOR
78# define DIRECTORY_SEPARATOR '/'
79#endif
80
81#ifndef ISSLASH
82# define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
83#endif
84
85#if HAVE_DECL_GETC_UNLOCKED
86# undef getc
87# define getc getc_unlocked
88#endif
89
90/* The following static variable is declared 'volatile' to avoid a
91 possible multithread problem in the function get_charset_aliases. If we
92 are running in a threaded environment, and if two threads initialize
93 'charset_aliases' simultaneously, both will produce the same value,
94 and everything will be ok if the two assignments to 'charset_aliases'
95 are atomic. But I don't know what will happen if the two assignments mix. */
96#if __STDC__ != 1
97# define volatile /* empty */
98#endif
99/* Pointer to the contents of the charset.alias file, if it has already been
100 read, else NULL. Its format is:
101 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
102static const char * volatile charset_aliases;
103
104/* Return a pointer to the contents of the charset.alias file. */
105static const char *
106get_charset_aliases (void)
107{
108 const char *cp;
109
110 cp = charset_aliases;
111 if (cp == NULL)
112 {
113#if !(defined VMS || defined WIN32_NATIVE || defined __CYGWIN__)
114 FILE *fp;
115 const char *dir;
116 const char *base = "charset.alias";
117 char *file_name;
118
119 /* Make it possible to override the charset.alias location. This is
120 necessary for running the testsuite before "make install". */
121 dir = getenv ("CHARSETALIASDIR");
122 if (dir == NULL || dir[0] == '\0')
123 dir = relocate (LIBDIR);
124
125 /* Concatenate dir and base into freshly allocated file_name. */
126 {
127 size_t dir_len = strlen (dir);
128 size_t base_len = strlen (base);
129 int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
130 file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
131 if (file_name != NULL)
132 {
133 memcpy (file_name, dir, dir_len);
134 if (add_slash)
135 file_name[dir_len] = DIRECTORY_SEPARATOR;
136 memcpy (file_name + dir_len + add_slash, base, base_len + 1);
137 }
138 }
139
140 if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
141 /* Out of memory or file not found, treat it as empty. */
142 cp = "";
143 else
144 {
145 /* Parse the file's contents. */
146 char *res_ptr = NULL;
147 size_t res_size = 0;
148
149 for (;;)
150 {
151 int c;
152 char buf1[50+1];
153 char buf2[50+1];
154 size_t l1, l2;
155 char *old_res_ptr;
156
157 c = getc (fp);
158 if (c == EOF)
159 break;
160 if (c == '\n' || c == ' ' || c == '\t')
161 continue;
162 if (c == '#')
163 {
164 /* Skip comment, to end of line. */
165 do
166 c = getc (fp);
167 while (!(c == EOF || c == '\n'));
168 if (c == EOF)
169 break;
170 continue;
171 }
172 ungetc (c, fp);
173 if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
174 break;
175 l1 = strlen (buf1);
176 l2 = strlen (buf2);
177 old_res_ptr = res_ptr;
178 if (res_size == 0)
179 {
180 res_size = l1 + 1 + l2 + 1;
181 res_ptr = (char *) malloc (res_size + 1);
182 }
183 else
184 {
185 res_size += l1 + 1 + l2 + 1;
186 res_ptr = (char *) realloc (res_ptr, res_size + 1);
187 }
188 if (res_ptr == NULL)
189 {
190 /* Out of memory. */
191 res_size = 0;
192 if (old_res_ptr != NULL)
193 free (old_res_ptr);
194 break;
195 }
196 strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
197 strcpy (res_ptr + res_size - (l2 + 1), buf2);
198 }
199 fclose (fp);
200 if (res_size == 0)
201 cp = "";
202 else
203 {
204 *(res_ptr + res_size) = '\0';
205 cp = res_ptr;
206 }
207 }
208
209 if (file_name != NULL)
210 free (file_name);
211
212#else
213
214# if defined VMS
215 /* To avoid the troubles of an extra file charset.alias_vms in the
216 sources of many GNU packages, simply inline the aliases here. */
217 /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
218 "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
219 section 10.7 "Handling Different Character Sets". */
220 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
221 "ISO8859-2" "\0" "ISO-8859-2" "\0"
222 "ISO8859-5" "\0" "ISO-8859-5" "\0"
223 "ISO8859-7" "\0" "ISO-8859-7" "\0"
224 "ISO8859-8" "\0" "ISO-8859-8" "\0"
225 "ISO8859-9" "\0" "ISO-8859-9" "\0"
226 /* Japanese */
227 "eucJP" "\0" "EUC-JP" "\0"
228 "SJIS" "\0" "SHIFT_JIS" "\0"
229 "DECKANJI" "\0" "DEC-KANJI" "\0"
230 "SDECKANJI" "\0" "EUC-JP" "\0"
231 /* Chinese */
232 "eucTW" "\0" "EUC-TW" "\0"
233 "DECHANYU" "\0" "DEC-HANYU" "\0"
234 "DECHANZI" "\0" "GB2312" "\0"
235 /* Korean */
236 "DECKOREAN" "\0" "EUC-KR" "\0";
237# endif
238
239# if defined WIN32_NATIVE || defined __CYGWIN__
240 /* To avoid the troubles of installing a separate file in the same
241 directory as the DLL and of retrieving the DLL's directory at
242 runtime, simply inline the aliases here. */
243
244 cp = "CP936" "\0" "GBK" "\0"
245 "CP1361" "\0" "JOHAB" "\0"
246 "CP20127" "\0" "ASCII" "\0"
247 "CP20866" "\0" "KOI8-R" "\0"
248 "CP20936" "\0" "GB2312" "\0"
249 "CP21866" "\0" "KOI8-RU" "\0"
250 "CP28591" "\0" "ISO-8859-1" "\0"
251 "CP28592" "\0" "ISO-8859-2" "\0"
252 "CP28593" "\0" "ISO-8859-3" "\0"
253 "CP28594" "\0" "ISO-8859-4" "\0"
254 "CP28595" "\0" "ISO-8859-5" "\0"
255 "CP28596" "\0" "ISO-8859-6" "\0"
256 "CP28597" "\0" "ISO-8859-7" "\0"
257 "CP28598" "\0" "ISO-8859-8" "\0"
258 "CP28599" "\0" "ISO-8859-9" "\0"
259 "CP28605" "\0" "ISO-8859-15" "\0"
260 "CP38598" "\0" "ISO-8859-8" "\0"
261 "CP51932" "\0" "EUC-JP" "\0"
262 "CP51936" "\0" "GB2312" "\0"
263 "CP51949" "\0" "EUC-KR" "\0"
264 "CP51950" "\0" "EUC-TW" "\0"
265 "CP54936" "\0" "GB18030" "\0"
266 "CP65001" "\0" "UTF-8" "\0";
267# endif
268#endif
269
270 charset_aliases = cp;
271 }
272
273 return cp;
274}
275
276/* Determine the current locale's character encoding, and canonicalize it
277 into one of the canonical names listed in config.charset.
278 The result must not be freed; it is statically allocated.
279 If the canonical name cannot be determined, the result is a non-canonical
280 name. */
281
282#ifdef STATIC
283STATIC
284#endif
285const char *
286locale_charset (void)
287{
288 const char *codeset;
289 const char *aliases;
290
291#if !(defined WIN32_NATIVE || defined OS2)
292
293# if HAVE_LANGINFO_CODESET
294
295 /* Most systems support nl_langinfo (CODESET) nowadays. */
296 codeset = nl_langinfo (CODESET);
297
298# ifdef __CYGWIN__
299 /* Cygwin 2006 does not have locales. nl_langinfo (CODESET) always
300 returns "US-ASCII". As long as this is not fixed, return the suffix
301 of the locale name from the environment variables (if present) or
302 the codepage as a number. */
303 if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
304 {
305 const char *locale;
306 static char buf[2 + 10 + 1];
307
308 locale = getenv ("LC_ALL");
309 if (locale == NULL || locale[0] == '\0')
310 {
311 locale = getenv ("LC_CTYPE");
312 if (locale == NULL || locale[0] == '\0')
313 locale = getenv ("LANG");
314 }
315 if (locale != NULL && locale[0] != '\0')
316 {
317 /* If the locale name contains an encoding after the dot, return
318 it. */
319 const char *dot = strchr (locale, '.');
320
321 if (dot != NULL)
322 {
323 const char *modifier;
324
325 dot++;
326 /* Look for the possible @... trailer and remove it, if any. */
327 modifier = strchr (dot, '@');
328 if (modifier == NULL)
329 return dot;
330 if (modifier - dot < sizeof (buf))
331 {
332 memcpy (buf, dot, modifier - dot);
333 buf [modifier - dot] = '\0';
334 return buf;
335 }
336 }
337 }
338
339 /* Woe32 has a function returning the locale's codepage as a number. */
340 sprintf (buf, "CP%u", GetACP ());
341 codeset = buf;
342 }
343# endif
344
345# else
346
347 /* On old systems which lack it, use setlocale or getenv. */
348 const char *locale = NULL;
349
350 /* But most old systems don't have a complete set of locales. Some
351 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
352 use setlocale here; it would return "C" when it doesn't support the
353 locale name the user has set. */
354# if 0
355 locale = setlocale (LC_CTYPE, NULL);
356# endif
357 if (locale == NULL || locale[0] == '\0')
358 {
359 locale = getenv ("LC_ALL");
360 if (locale == NULL || locale[0] == '\0')
361 {
362 locale = getenv ("LC_CTYPE");
363 if (locale == NULL || locale[0] == '\0')
364 locale = getenv ("LANG");
365 }
366 }
367
368 /* On some old systems, one used to set locale = "iso8859_1". On others,
369 you set it to "language_COUNTRY.charset". In any case, we resolve it
370 through the charset.alias file. */
371 codeset = locale;
372
373# endif
374
375#elif defined WIN32_NATIVE
376
377 static char buf[2 + 10 + 1];
378
379 /* Woe32 has a function returning the locale's codepage as a number. */
380 sprintf (buf, "CP%u", GetACP ());
381 codeset = buf;
382
383#elif defined OS2
384
385 const char *locale;
386 static char buf[2 + 10 + 1];
387 ULONG cp[3];
388 ULONG cplen;
389
390 /* Allow user to override the codeset, as set in the operating system,
391 with standard language environment variables. */
392 locale = getenv ("LC_ALL");
393 if (locale == NULL || locale[0] == '\0')
394 {
395 locale = getenv ("LC_CTYPE");
396 if (locale == NULL || locale[0] == '\0')
397 locale = getenv ("LANG");
398 }
399 if (locale != NULL && locale[0] != '\0')
400 {
401 /* If the locale name contains an encoding after the dot, return it. */
402 const char *dot = strchr (locale, '.');
403
404 if (dot != NULL)
405 {
406 const char *modifier;
407
408 dot++;
409 /* Look for the possible @... trailer and remove it, if any. */
410 modifier = strchr (dot, '@');
411 if (modifier == NULL)
412 return dot;
413 if (modifier - dot < sizeof (buf))
414 {
415 memcpy (buf, dot, modifier - dot);
416 buf [modifier - dot] = '\0';
417 return buf;
418 }
419 }
420
421 /* Resolve through the charset.alias file. */
422 codeset = locale;
423 }
424 else
425 {
426 /* OS/2 has a function returning the locale's codepage as a number. */
427 if (DosQueryCp (sizeof (cp), cp, &cplen))
428 codeset = "";
429 else
430 {
431 sprintf (buf, "CP%u", cp[0]);
432 codeset = buf;
433 }
434 }
435
436#endif
437
438 if (codeset == NULL)
439 /* The canonical name cannot be determined. */
440 codeset = "";
441
442 /* Resolve alias. */
443 for (aliases = get_charset_aliases ();
444 *aliases != '\0';
445 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
446 if (strcmp (codeset, aliases) == 0
447 || (aliases[0] == '*' && aliases[1] == '\0'))
448 {
449 codeset = aliases + strlen (aliases) + 1;
450 break;
451 }
452
453 /* Don't return an empty string. GNU libc and GNU libiconv interpret
454 the empty string as denoting "the locale's character encoding",
455 thus GNU libiconv would call this function a second time. */
456 if (codeset[0] == '\0')
457 codeset = "ASCII";
458
459 return codeset;
460}
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