lib/intl/localcharset.c

   1 /* localcharset.c - Determine a canonical name for the current locale's character encoding. */
   2
   3 /* Copyright (C) 2000-2003, 2005-2009 Free Software Foundation, Inc.
   4
   5    This file is part of GNU Bush.
   6
   7    Bush is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    Bush is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with Bush.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 /* Written by Bruno Haible <bruno@clisp.org>.  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 /* Specification.  */
  28 #include "localcharset.h"
  29
  30 #if HAVE_STDDEF_H
  31 # include <stddef.h>
  32 #endif
  33
  34 #include <stdio.h>
  35 #if HAVE_STRING_H
  36 # include <string.h>
  37 #else
  38 # include <strings.h>
  39 #endif
  40 #if HAVE_STDLIB_H
  41 # include <stdlib.h>
  42 #endif
  43
  44 #if defined _WIN32 || defined __WIN32__
  45 # undef WIN32   /* avoid warning on mingw32 */
  46 # define WIN32
  47 #endif
  48
  49 #if defined __EMX__
  50 /* Assume EMX program runs on OS/2, even if compiled under DOS.  */
  51 # define OS2
  52 #endif
  53
  54 #if !defined WIN32
  55 # if HAVE_LANGINFO_CODESET
  56 #  include <langinfo.h>
  57 # else
  58 #  if HAVE_SETLOCALE
  59 #   include <locale.h>
  60 #  endif
  61 # endif
  62 #elif defined WIN32
  63 # define WIN32_LEAN_AND_MEAN
  64 # include <windows.h>
  65 #endif
  66 #if defined OS2
  67 # define INCL_DOS
  68 # include <os2.h>
  69 #endif
  70
  71 #if ENABLE_RELOCATABLE
  72 # include "relocatable.h"
  73 #else
  74 # define relocate(pathname) (pathname)
  75 #endif
  76
  77 #if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__
  78   /* Win32, OS/2, DOS */
  79 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
  80 #endif
  81
  82 #ifndef DIRECTORY_SEPARATOR
  83 # define DIRECTORY_SEPARATOR '/'
  84 #endif
  85
  86 #ifndef ISSLASH
  87 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
  88 #endif
  89
  90 #ifdef HAVE_GETC_UNLOCKED
  91 # undef getc
  92 # define getc getc_unlocked
  93 #endif
  94
  95 /* The following static variable is declared 'volatile' to avoid a
  96    possible multithread problem in the function get_charset_aliases. If we
  97    are running in a threaded environment, and if two threads initialize
  98    'charset_aliases' simultaneously, both will produce the same value,
  99    and everything will be ok if the two assignments to 'charset_aliases'
 100    are atomic. But I don't know what will happen if the two assignments mix.  */
 101 #if __STDC__ != 1
 102 # define volatile /* empty */
 103 #endif
 104 /* Pointer to the contents of the charset.alias file, if it has already been
 105    read, else NULL.  Its format is:
 106    ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0'  */
 107 static const char * volatile charset_aliases;
 108
 109 /* Return a pointer to the contents of the charset.alias file.  */
 110 static const char *
 111 get_charset_aliases ()
 112 {
 113   const char *cp;
 114
 115   cp = charset_aliases;
 116   if (cp == NULL)
 117     {
 118 #if !(defined VMS || defined WIN32)
 119       FILE *fp;
 120       const char *dir = relocate (LIBDIR);
 121       const char *base = "charset.alias";
 122       char *file_name;
 123
 124       /* Concatenate dir and base into freshly allocated file_name.  */
 125       {
 126         size_t dir_len = strlen (dir);
 127         size_t base_len = strlen (base);
 128         int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
 129         file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
 130         if (file_name != NULL)
 131           {
 132             memcpy (file_name, dir, dir_len);
 133             if (add_slash)
 134               file_name[dir_len] = DIRECTORY_SEPARATOR;
 135             memcpy (file_name + dir_len + add_slash, base, base_len + 1);
 136           }
 137       }
 138
 139       if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
 140         /* Out of memory or file not found, treat it as empty.  */
 141         cp = "";
 142       else
 143         {
 144           /* Parse the file's contents.  */
 145           int c;
 146           char buf1[50+1];
 147           char buf2[50+1];
 148           char *res_ptr = NULL;
 149           size_t res_size = 0;
 150           size_t l1, l2;
 151
 152           for (;;)
 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               if (res_size == 0)
 175                 {
 176                   res_size = l1 + 1 + l2 + 1;
 177                   res_ptr = (char *) malloc (res_size + 1);
 178                 }
 179               else
 180                 {
 181                   res_size += l1 + 1 + l2 + 1;
 182                   res_ptr = (char *) realloc (res_ptr, res_size + 1);
 183                 }
 184               if (res_ptr == NULL)
 185                 {
 186                   /* Out of memory. */
 187                   res_size = 0;
 188                   break;
 189                 }
 190               strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
 191               strcpy (res_ptr + res_size - (l2 + 1), buf2);
 192             }
 193           fclose (fp);
 194           if (res_size == 0)
 195             cp = "";
 196           else
 197             {
 198               *(res_ptr + res_size) = '\0';
 199               cp = res_ptr;
 200             }
 201         }
 202
 203       if (file_name != NULL)
 204         free (file_name);
 205
 206 #else
 207
 208 # if defined VMS
 209       /* To avoid the troubles of an extra file charset.alias_vms in the
 210          sources of many GNU packages, simply inline the aliases here.  */
 211       /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
 212          "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
 213          section 10.7 "Handling Different Character Sets".  */
 214       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 215            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 216            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 217            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 218            "ISO8859-8" "\0" "ISO-8859-8" "\0"
 219            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 220            /* Japanese */
 221            "eucJP" "\0" "EUC-JP" "\0"
 222            "SJIS" "\0" "SHIFT_JIS" "\0"
 223            "DECKANJI" "\0" "DEC-KANJI" "\0"
 224            "SDECKANJI" "\0" "EUC-JP" "\0"
 225            /* Chinese */
 226            "eucTW" "\0" "EUC-TW" "\0"
 227            "DECHANYU" "\0" "DEC-HANYU" "\0"
 228            "DECHANZI" "\0" "GB2312" "\0"
 229            /* Korean */
 230            "DECKOREAN" "\0" "EUC-KR" "\0";
 231 # endif
 232
 233 # if defined WIN32
 234       /* To avoid the troubles of installing a separate file in the same
 235          directory as the DLL and of retrieving the DLL's directory at
 236          runtime, simply inline the aliases here.  */
 237
 238       cp = "CP936" "\0" "GBK" "\0"
 239            "CP1361" "\0" "JOHAB" "\0"
 240            "CP20127" "\0" "ASCII" "\0"
 241            "CP20866" "\0" "KOI8-R" "\0"
 242            "CP21866" "\0" "KOI8-RU" "\0"
 243            "CP28591" "\0" "ISO-8859-1" "\0"
 244            "CP28592" "\0" "ISO-8859-2" "\0"
 245            "CP28593" "\0" "ISO-8859-3" "\0"
 246            "CP28594" "\0" "ISO-8859-4" "\0"
 247            "CP28595" "\0" "ISO-8859-5" "\0"
 248            "CP28596" "\0" "ISO-8859-6" "\0"
 249            "CP28597" "\0" "ISO-8859-7" "\0"
 250            "CP28598" "\0" "ISO-8859-8" "\0"
 251            "CP28599" "\0" "ISO-8859-9" "\0"
 252            "CP28605" "\0" "ISO-8859-15" "\0";
 253 # endif
 254 #endif
 255
 256       charset_aliases = cp;
 257     }
 258
 259   return cp;
 260 }
 261
 262 /* Determine the current locale's character encoding, and canonicalize it
 263    into one of the canonical names listed in config.charset.
 264    The result must not be freed; it is statically allocated.
 265    If the canonical name cannot be determined, the result is a non-canonical
 266    name.  */
 267
 268 #ifdef STATIC
 269 STATIC
 270 #endif
 271 const char *
 272 locale_charset ()
 273 {
 274   const char *codeset;
 275   const char *aliases;
 276
 277 #if !(defined WIN32 || defined OS2)
 278
 279 # if HAVE_LANGINFO_CODESET
 280
 281   /* Most systems support nl_langinfo (CODESET) nowadays.  */
 282   codeset = nl_langinfo (CODESET);
 283
 284 # else
 285
 286   /* On old systems which lack it, use setlocale or getenv.  */
 287   const char *locale = NULL;
 288
 289   /* But most old systems don't have a complete set of locales.  Some
 290      (like SunOS 4 or DJGPP) have only the C locale.  Therefore we don't
 291      use setlocale here; it would return "C" when it doesn't support the
 292      locale name the user has set.  */
 293 #  if HAVE_SETLOCALE && 0
 294   locale = setlocale (LC_CTYPE, NULL);
 295 #  endif
 296   if (locale == NULL || locale[0] == '\0')
 297     {
 298       locale = getenv ("LC_ALL");
 299       if (locale == NULL || locale[0] == '\0')
 300         {
 301           locale = getenv ("LC_CTYPE");
 302           if (locale == NULL || locale[0] == '\0')
 303             locale = getenv ("LANG");
 304         }
 305     }
 306
 307   /* On some old systems, one used to set locale = "iso8859_1". On others,
 308      you set it to "language_COUNTRY.charset". In any case, we resolve it
 309      through the charset.alias file.  */
 310   codeset = locale;
 311
 312 # endif
 313
 314 #elif defined WIN32
 315
 316   static char buf[2 + 10 + 1];
 317
 318   /* Woe32 has a function returning the locale's codepage as a number.  */
 319   sprintf (buf, "CP%u", GetACP ());
 320   codeset = buf;
 321
 322 #elif defined OS2
 323
 324   const char *locale;
 325   static char buf[2 + 10 + 1];
 326   ULONG cp[3];
 327   ULONG cplen;
 328
 329   /* Allow user to override the codeset, as set in the operating system,
 330      with standard language environment variables.  */
 331   locale = getenv ("LC_ALL");
 332   if (locale == NULL || locale[0] == '\0')
 333     {
 334       locale = getenv ("LC_CTYPE");
 335       if (locale == NULL || locale[0] == '\0')
 336         locale = getenv ("LANG");
 337     }
 338   if (locale != NULL && locale[0] != '\0')
 339     {
 340       /* If the locale name contains an encoding after the dot, return it.  */
 341       const char *dot = strchr (locale, '.');
 342
 343       if (dot != NULL)
 344         {
 345           const char *modifier;
 346
 347           dot++;
 348           /* Look for the possible @... trailer and remove it, if any.  */
 349           modifier = strchr (dot, '@');
 350           if (modifier == NULL)
 351             return dot;
 352           if (modifier - dot < sizeof (buf))
 353             {
 354               memcpy (buf, dot, modifier - dot);
 355               buf [modifier - dot] = '\0';
 356               return buf;
 357             }
 358         }
 359
 360       /* Resolve through the charset.alias file.  */
 361       codeset = locale;
 362     }
 363   else
 364     {
 365       /* OS/2 has a function returning the locale's codepage as a number.  */
 366       if (DosQueryCp (sizeof (cp), cp, &cplen))
 367         codeset = "";
 368       else
 369         {
 370           sprintf (buf, "CP%u", cp[0]);
 371           codeset = buf;
 372         }
 373     }
 374
 375 #endif
 376
 377   if (codeset == NULL)
 378     /* The canonical name cannot be determined.  */
 379     codeset = "";
 380
 381   /* Resolve alias. */
 382   for (aliases = get_charset_aliases ();
 383        *aliases != '\0';
 384        aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
 385     if (strcmp (codeset, aliases) == 0
 386         || (aliases[0] == '*' && aliases[1] == '\0'))
 387       {
 388         codeset = aliases + strlen (aliases) + 1;
 389         break;
 390       }
 391
 392   /* Don't return an empty string.  GNU libc and GNU libiconv interpret
 393      the empty string as denoting "the locale's character encoding",
 394      thus GNU libiconv would call this function a second time.  */
 395   if (codeset[0] == '\0')
 396     codeset = "ASCII";
 397
 398   return codeset;
 399 }