summaryrefslogtreecommitdiff
path: root/lib/localcharset.c
blob: 10c69b067d5f19d4a5639920538c3f8f2d04482a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/* Determine a canonical name for the current locale's character encoding.

   Copyright (C) 2000-2004 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

/* Written by Bruno Haible <bruno@clisp.org>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

/* Specification.  */
#include "localcharset.h"

#if HAVE_STDDEF_H
# include <stddef.h>
#endif

#include <stdio.h>
#if HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
#endif
#if HAVE_STDLIB_H
# include <stdlib.h>
#endif

#if defined _WIN32 || defined __WIN32__
# undef WIN32   /* avoid warning on mingw32 */
# define WIN32
#endif

#if defined __EMX__
/* Assume EMX program runs on OS/2, even if compiled under DOS.  */
# define OS2
#endif

#if !defined WIN32
# if HAVE_LANGINFO_CODESET
#  include <langinfo.h>
# else
#  if HAVE_SETLOCALE
#   include <locale.h>
#  endif
# endif
#elif defined WIN32
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif
#if defined OS2
# define INCL_DOS
# include <os2.h>
#endif

#if ENABLE_RELOCATABLE
# include "relocatable.h"
#else
# define relocate(pathname) (pathname)
#endif

#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
  /* Win32, Cygwin, OS/2, DOS */
# define ISSLASH(C) ((C) == '/' || (C) == '\\')
#endif

#ifndef DIRECTORY_SEPARATOR
# define DIRECTORY_SEPARATOR '/'
#endif

#ifndef ISSLASH
# define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
#endif

#if HAVE_DECL_GETC_UNLOCKED
# undef getc
# define getc getc_unlocked
#endif

/* The following static variable is declared 'volatile' to avoid a
   possible multithread problem in the function get_charset_aliases. If we
   are running in a threaded environment, and if two threads initialize
   'charset_aliases' simultaneously, both will produce the same value,
   and everything will be ok if the two assignments to 'charset_aliases'
   are atomic. But I don't know what will happen if the two assignments mix.  */
#if __STDC__ != 1
# define volatile /* empty */
#endif
/* Pointer to the contents of the charset.alias file, if it has already been
   read, else NULL.  Its format is:
   ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0'  */
static const char * volatile charset_aliases;

/* Return a pointer to the contents of the charset.alias file.  */
static const char *
get_charset_aliases ()
{
  const char *cp;

  cp = charset_aliases;
  if (cp == NULL)
    {
#if !(defined VMS || defined WIN32)
      FILE *fp;
      const char *dir;
      const char *base = "charset.alias";
      char *file_name;

      /* Make it possible to override the charset.alias location.  This is
	 necessary for running the testsuite before "make install".  */
      dir = getenv ("CHARSETALIASDIR");
      if (dir == NULL || dir[0] == '\0')
	dir = relocate (LIBDIR);

      /* Concatenate dir and base into freshly allocated file_name.  */
      {
	size_t dir_len = strlen (dir);
	size_t base_len = strlen (base);
	int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
	file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
	if (file_name != NULL)
	  {
	    memcpy (file_name, dir, dir_len);
	    if (add_slash)
	      file_name[dir_len] = DIRECTORY_SEPARATOR;
	    memcpy (file_name + dir_len + add_slash, base, base_len + 1);
	  }
      }

      if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
	/* Out of memory or file not found, treat it as empty.  */
	cp = "";
      else
	{
	  /* Parse the file's contents.  */
	  char *res_ptr = NULL;
	  size_t res_size = 0;

	  for (;;)
	    {
	      int c;
	      char buf1[50+1];
	      char buf2[50+1];
	      size_t l1, l2;
	      char *old_res_ptr;

	      c = getc (fp);
	      if (c == EOF)
		break;
	      if (c == '\n' || c == ' ' || c == '\t')
		continue;
	      if (c == '#')
		{
		  /* Skip comment, to end of line.  */
		  do
		    c = getc (fp);
		  while (!(c == EOF || c == '\n'));
		  if (c == EOF)
		    break;
		  continue;
		}
	      ungetc (c, fp);
	      if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
		break;
	      l1 = strlen (buf1);
	      l2 = strlen (buf2);
	      old_res_ptr = res_ptr;
	      if (res_size == 0)
		{
		  res_size = l1 + 1 + l2 + 1;
		  res_ptr = (char *) malloc (res_size + 1);
		}
	      else
		{
		  res_size += l1 + 1 + l2 + 1;
		  res_ptr = (char *) realloc (res_ptr, res_size + 1);
		}
	      if (res_ptr == NULL)
		{
		  /* Out of memory. */
		  res_size = 0;
		  if (old_res_ptr != NULL)
		    free (old_res_ptr);
		  break;
		}
	      strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
	      strcpy (res_ptr + res_size - (l2 + 1), buf2);
	    }
	  fclose (fp);
	  if (res_size == 0)
	    cp = "";
	  else
	    {
	      *(res_ptr + res_size) = '\0';
	      cp = res_ptr;
	    }
	}

      if (file_name != NULL)
	free (file_name);

#else

# if defined VMS
      /* To avoid the troubles of an extra file charset.alias_vms in the
	 sources of many GNU packages, simply inline the aliases here.  */
      /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
	 "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
	 section 10.7 "Handling Different Character Sets".  */
      cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
	   "ISO8859-2" "\0" "ISO-8859-2" "\0"
	   "ISO8859-5" "\0" "ISO-8859-5" "\0"
	   "ISO8859-7" "\0" "ISO-8859-7" "\0"
	   "ISO8859-8" "\0" "ISO-8859-8" "\0"
	   "ISO8859-9" "\0" "ISO-8859-9" "\0"
	   /* Japanese */
	   "eucJP" "\0" "EUC-JP" "\0"
	   "SJIS" "\0" "SHIFT_JIS" "\0"
	   "DECKANJI" "\0" "DEC-KANJI" "\0"
	   "SDECKANJI" "\0" "EUC-JP" "\0"
	   /* Chinese */
	   "eucTW" "\0" "EUC-TW" "\0"
	   "DECHANYU" "\0" "DEC-HANYU" "\0"
	   "DECHANZI" "\0" "GB2312" "\0"
	   /* Korean */
	   "DECKOREAN" "\0" "EUC-KR" "\0";
# endif

# if defined WIN32
      /* To avoid the troubles of installing a separate file in the same
	 directory as the DLL and of retrieving the DLL's directory at
	 runtime, simply inline the aliases here.  */

      cp = "CP936" "\0" "GBK" "\0"
	   "CP1361" "\0" "JOHAB" "\0"
	   "CP20127" "\0" "ASCII" "\0"
	   "CP20866" "\0" "KOI8-R" "\0"
	   "CP21866" "\0" "KOI8-RU" "\0"
	   "CP28591" "\0" "ISO-8859-1" "\0"
	   "CP28592" "\0" "ISO-8859-2" "\0"
	   "CP28593" "\0" "ISO-8859-3" "\0"
	   "CP28594" "\0" "ISO-8859-4" "\0"
	   "CP28595" "\0" "ISO-8859-5" "\0"
	   "CP28596" "\0" "ISO-8859-6" "\0"
	   "CP28597" "\0" "ISO-8859-7" "\0"
	   "CP28598" "\0" "ISO-8859-8" "\0"
	   "CP28599" "\0" "ISO-8859-9" "\0"
	   "CP28605" "\0" "ISO-8859-15" "\0";
# endif
#endif

      charset_aliases = cp;
    }

  return cp;
}

/* Determine the current locale's character encoding, and canonicalize it
   into one of the canonical names listed in config.charset.
   The result must not be freed; it is statically allocated.
   If the canonical name cannot be determined, the result is a non-canonical
   name.  */

#ifdef STATIC
STATIC
#endif
const char *
locale_charset ()
{
  const char *codeset;
  const char *aliases;

#if !(defined WIN32 || defined OS2)

# if HAVE_LANGINFO_CODESET

  /* Most systems support nl_langinfo (CODESET) nowadays.  */
  codeset = nl_langinfo (CODESET);

# else

  /* On old systems which lack it, use setlocale or getenv.  */
  const char *locale = NULL;

  /* But most old systems don't have a complete set of locales.  Some
     (like SunOS 4 or DJGPP) have only the C locale.  Therefore we don't
     use setlocale here; it would return "C" when it doesn't support the
     locale name the user has set.  */
#  if HAVE_SETLOCALE && 0
  locale = setlocale (LC_CTYPE, NULL);
#  endif
  if (locale == NULL || locale[0] == '\0')
    {
      locale = getenv ("LC_ALL");
      if (locale == NULL || locale[0] == '\0')
	{
	  locale = getenv ("LC_CTYPE");
	  if (locale == NULL || locale[0] == '\0')
	    locale = getenv ("LANG");
	}
    }

  /* On some old systems, one used to set locale = "iso8859_1". On others,
     you set it to "language_COUNTRY.charset". In any case, we resolve it
     through the charset.alias file.  */
  codeset = locale;

# endif

#elif defined WIN32

  static char buf[2 + 10 + 1];

  /* Woe32 has a function returning the locale's codepage as a number.  */
  sprintf (buf, "CP%u", GetACP ());
  codeset = buf;

#elif defined OS2

  const char *locale;
  static char buf[2 + 10 + 1];
  ULONG cp[3];
  ULONG cplen;

  /* Allow user to override the codeset, as set in the operating system,
     with standard language environment variables.  */
  locale = getenv ("LC_ALL");
  if (locale == NULL || locale[0] == '\0')
    {
      locale = getenv ("LC_CTYPE");
      if (locale == NULL || locale[0] == '\0')
	locale = getenv ("LANG");
    }
  if (locale != NULL && locale[0] != '\0')
    {
      /* If the locale name contains an encoding after the dot, return it.  */
      const char *dot = strchr (locale, '.');

      if (dot != NULL)
	{
	  const char *modifier;

	  dot++;
	  /* Look for the possible @... trailer and remove it, if any.  */
	  modifier = strchr (dot, '@');
	  if (modifier == NULL)
	    return dot;
	  if (modifier - dot < sizeof (buf))
	    {
	      memcpy (buf, dot, modifier - dot);
	      buf [modifier - dot] = '\0';
	      return buf;
	    }
	}

      /* Resolve through the charset.alias file.  */
      codeset = locale;
    }
  else
    {
      /* OS/2 has a function returning the locale's codepage as a number.  */
      if (DosQueryCp (sizeof (cp), cp, &cplen))
	codeset = "";
      else
	{
	  sprintf (buf, "CP%u", cp[0]);
	  codeset = buf;
	}
    }

#endif

  if (codeset == NULL)
    /* The canonical name cannot be determined.  */
    codeset = "";

  /* Resolve alias. */
  for (aliases = get_charset_aliases ();
       *aliases != '\0';
       aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
    if (strcmp (codeset, aliases) == 0
	|| (aliases[0] == '*' && aliases[1] == '\0'))
      {
	codeset = aliases + strlen (aliases) + 1;
	break;
      }

  /* Don't return an empty string.  GNU libc and GNU libiconv interpret
     the empty string as denoting "the locale's character encoding",
     thus GNU libiconv would call this function a second time.  */
  if (codeset[0] == '\0')
    codeset = "ASCII";

  return codeset;
}