gl/localcharset.c

   1 /* Determine a canonical name for the current locale's character encoding.
   2
   3    Copyright (C) 2000-2006, 2008-2009 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 3, 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 __APPLE__ && defined __MACH__ && HAVE_LANGINFO_CODESET
  32 # define DARWIN7 /* Darwin 7 or newer, i.e. MacOS X 10.3 or newer */
  33 #endif
  34
  35 #if defined _WIN32 || defined __WIN32__
  36 # define WIN32_NATIVE
  37 #endif
  38
  39 #if defined __EMX__
  40 /* Assume EMX program runs on OS/2, even if compiled under DOS.  */
  41 # ifndef OS2
  42 #  define OS2
  43 # endif
  44 #endif
  45
  46 #if !defined WIN32_NATIVE
  47 # if HAVE_LANGINFO_CODESET
  48 #  include <langinfo.h>
  49 # else
  50 #  if 0 /* see comment below */
  51 #   include <locale.h>
  52 #  endif
  53 # endif
  54 # ifdef __CYGWIN__
  55 #  define WIN32_LEAN_AND_MEAN
  56 #  include <windows.h>
  57 # endif
  58 #elif defined WIN32_NATIVE
  59 # define WIN32_LEAN_AND_MEAN
  60 # include <windows.h>
  61 #endif
  62 #if defined OS2
  63 # define INCL_DOS
  64 # include <os2.h>
  65 #endif
  66
  67 #if ENABLE_RELOCATABLE
  68 # include "relocatable.h"
  69 #else
  70 # define relocate(pathname) (pathname)
  71 #endif
  72
  73 /* Get LIBDIR.  */
  74 #ifndef LIBDIR
  75 # include "configmake.h"
  76 #endif
  77
  78 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
  79   /* Win32, Cygwin, OS/2, DOS */
  80 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
  81 #endif
  82
  83 #ifndef DIRECTORY_SEPARATOR
  84 # define DIRECTORY_SEPARATOR '/'
  85 #endif
  86
  87 #ifndef ISSLASH
  88 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
  89 #endif
  90
  91 #if HAVE_DECL_GETC_UNLOCKED
  92 # undef getc
  93 # define getc getc_unlocked
  94 #endif
  95
  96 /* The following static variable is declared 'volatile' to avoid a
  97    possible multithread problem in the function get_charset_aliases. If we
  98    are running in a threaded environment, and if two threads initialize
  99    'charset_aliases' simultaneously, both will produce the same value,
 100    and everything will be ok if the two assignments to 'charset_aliases'
 101    are atomic. But I don't know what will happen if the two assignments mix.  */
 102 #if __STDC__ != 1
 103 # define volatile /* empty */
 104 #endif
 105 /* Pointer to the contents of the charset.alias file, if it has already been
 106    read, else NULL.  Its format is:
 107    ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0'  */
 108 static const char * volatile charset_aliases;
 109
 110 /* Return a pointer to the contents of the charset.alias file.  */
 111 static const char *
 112 get_charset_aliases (void)
 113 {
 114   const char *cp;
 115
 116   cp = charset_aliases;
 117   if (cp == NULL)
 118     {
 119 #if !(defined DARWIN7 || defined VMS || defined WIN32_NATIVE || defined __CYGWIN__)
 120       FILE *fp;
 121       const char *dir;
 122       const char *base = "charset.alias";
 123       char *file_name;
 124
 125       /* Make it possible to override the charset.alias location.  This is
 126          necessary for running the testsuite before "make install".  */
 127       dir = getenv ("CHARSETALIASDIR");
 128       if (dir == NULL || dir[0] == '\0')
 129         dir = relocate (LIBDIR);
 130
 131       /* Concatenate dir and base into freshly allocated file_name.  */
 132       {
 133         size_t dir_len = strlen (dir);
 134         size_t base_len = strlen (base);
 135         int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
 136         file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
 137         if (file_name != NULL)
 138           {
 139             memcpy (file_name, dir, dir_len);
 140             if (add_slash)
 141               file_name[dir_len] = DIRECTORY_SEPARATOR;
 142             memcpy (file_name + dir_len + add_slash, base, base_len + 1);
 143           }
 144       }
 145
 146       if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
 147         /* Out of memory or file not found, treat it as empty.  */
 148         cp = "";
 149       else
 150         {
 151           /* Parse the file's contents.  */
 152           char *res_ptr = NULL;
 153           size_t res_size = 0;
 154
 155           for (;;)
 156             {
 157               int c;
 158               char buf1[50+1];
 159               char buf2[50+1];
 160               size_t l1, l2;
 161               char *old_res_ptr;
 162
 163               c = getc (fp);
 164               if (c == EOF)
 165                 break;
 166               if (c == '\n' || c == ' ' || c == '\t')
 167                 continue;
 168               if (c == '#')
 169                 {
 170                   /* Skip comment, to end of line.  */
 171                   do
 172                     c = getc (fp);
 173                   while (!(c == EOF || c == '\n'));
 174                   if (c == EOF)
 175                     break;
 176                   continue;
 177                 }
 178               ungetc (c, fp);
 179               if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
 180                 break;
 181               l1 = strlen (buf1);
 182               l2 = strlen (buf2);
 183               old_res_ptr = res_ptr;
 184               if (res_size == 0)
 185                 {
 186                   res_size = l1 + 1 + l2 + 1;
 187                   res_ptr = (char *) malloc (res_size + 1);
 188                 }
 189               else
 190                 {
 191                   res_size += l1 + 1 + l2 + 1;
 192                   res_ptr = (char *) realloc (res_ptr, res_size + 1);
 193                 }
 194               if (res_ptr == NULL)
 195                 {
 196                   /* Out of memory. */
 197                   res_size = 0;
 198                   if (old_res_ptr != NULL)
 199                     free (old_res_ptr);
 200                   break;
 201                 }
 202               strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
 203               strcpy (res_ptr + res_size - (l2 + 1), buf2);
 204             }
 205           fclose (fp);
 206           if (res_size == 0)
 207             cp = "";
 208           else
 209             {
 210               *(res_ptr + res_size) = '\0';
 211               cp = res_ptr;
 212             }
 213         }
 214
 215       if (file_name != NULL)
 216         free (file_name);
 217
 218 #else
 219
 220 # if defined DARWIN7
 221       /* To avoid the trouble of installing a file that is shared by many
 222          GNU packages -- many packaging systems have problems with this --,
 223          simply inline the aliases here.  */
 224       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 225            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 226            "ISO8859-4" "\0" "ISO-8859-4" "\0"
 227            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 228            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 229            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 230            "ISO8859-13" "\0" "ISO-8859-13" "\0"
 231            "ISO8859-15" "\0" "ISO-8859-15" "\0"
 232            "KOI8-R" "\0" "KOI8-R" "\0"
 233            "KOI8-U" "\0" "KOI8-U" "\0"
 234            "CP866" "\0" "CP866" "\0"
 235            "CP949" "\0" "CP949" "\0"
 236            "CP1131" "\0" "CP1131" "\0"
 237            "CP1251" "\0" "CP1251" "\0"
 238            "eucCN" "\0" "GB2312" "\0"
 239            "GB2312" "\0" "GB2312" "\0"
 240            "eucJP" "\0" "EUC-JP" "\0"
 241            "eucKR" "\0" "EUC-KR" "\0"
 242            "Big5" "\0" "BIG5" "\0"
 243            "Big5HKSCS" "\0" "BIG5-HKSCS" "\0"
 244            "GBK" "\0" "GBK" "\0"
 245            "GB18030" "\0" "GB18030" "\0"
 246            "SJIS" "\0" "SHIFT_JIS" "\0"
 247            "ARMSCII-8" "\0" "ARMSCII-8" "\0"
 248            "PT154" "\0" "PT154" "\0"
 249          /*"ISCII-DEV" "\0" "?" "\0"*/
 250            "*" "\0" "UTF-8" "\0";
 251 # endif
 252
 253 # if defined VMS
 254       /* To avoid the troubles of an extra file charset.alias_vms in the
 255          sources of many GNU packages, simply inline the aliases here.  */
 256       /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
 257          "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
 258          section 10.7 "Handling Different Character Sets".  */
 259       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 260            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 261            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 262            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 263            "ISO8859-8" "\0" "ISO-8859-8" "\0"
 264            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 265            /* Japanese */
 266            "eucJP" "\0" "EUC-JP" "\0"
 267            "SJIS" "\0" "SHIFT_JIS" "\0"
 268            "DECKANJI" "\0" "DEC-KANJI" "\0"
 269            "SDECKANJI" "\0" "EUC-JP" "\0"
 270            /* Chinese */
 271            "eucTW" "\0" "EUC-TW" "\0"
 272            "DECHANYU" "\0" "DEC-HANYU" "\0"
 273            "DECHANZI" "\0" "GB2312" "\0"
 274            /* Korean */
 275            "DECKOREAN" "\0" "EUC-KR" "\0";
 276 # endif
 277
 278 # if defined WIN32_NATIVE || defined __CYGWIN__
 279       /* To avoid the troubles of installing a separate file in the same
 280          directory as the DLL and of retrieving the DLL's directory at
 281          runtime, simply inline the aliases here.  */
 282
 283       cp = "CP936" "\0" "GBK" "\0"
 284            "CP1361" "\0" "JOHAB" "\0"
 285            "CP20127" "\0" "ASCII" "\0"
 286            "CP20866" "\0" "KOI8-R" "\0"
 287            "CP20936" "\0" "GB2312" "\0"
 288            "CP21866" "\0" "KOI8-RU" "\0"
 289            "CP28591" "\0" "ISO-8859-1" "\0"
 290            "CP28592" "\0" "ISO-8859-2" "\0"
 291            "CP28593" "\0" "ISO-8859-3" "\0"
 292            "CP28594" "\0" "ISO-8859-4" "\0"
 293            "CP28595" "\0" "ISO-8859-5" "\0"
 294            "CP28596" "\0" "ISO-8859-6" "\0"
 295            "CP28597" "\0" "ISO-8859-7" "\0"
 296            "CP28598" "\0" "ISO-8859-8" "\0"
 297            "CP28599" "\0" "ISO-8859-9" "\0"
 298            "CP28605" "\0" "ISO-8859-15" "\0"
 299            "CP38598" "\0" "ISO-8859-8" "\0"
 300            "CP51932" "\0" "EUC-JP" "\0"
 301            "CP51936" "\0" "GB2312" "\0"
 302            "CP51949" "\0" "EUC-KR" "\0"
 303            "CP51950" "\0" "EUC-TW" "\0"
 304            "CP54936" "\0" "GB18030" "\0"
 305            "CP65001" "\0" "UTF-8" "\0";
 306 # endif
 307 #endif
 308
 309       charset_aliases = cp;
 310     }
 311
 312   return cp;
 313 }
 314
 315 /* Determine the current locale's character encoding, and canonicalize it
 316    into one of the canonical names listed in config.charset.
 317    The result must not be freed; it is statically allocated.
 318    If the canonical name cannot be determined, the result is a non-canonical
 319    name.  */
 320
 321 #ifdef STATIC
 322 STATIC
 323 #endif
 324 const char *
 325 locale_charset (void)
 326 {
 327   const char *codeset;
 328   const char *aliases;
 329
 330 #if !(defined WIN32_NATIVE || defined OS2)
 331
 332 # if HAVE_LANGINFO_CODESET
 333
 334   /* Most systems support nl_langinfo (CODESET) nowadays.  */
 335   codeset = nl_langinfo (CODESET);
 336
 337 #  ifdef __CYGWIN__
 338   /* Cygwin 2006 does not have locales.  nl_langinfo (CODESET) always
 339      returns "US-ASCII".  As long as this is not fixed, return the suffix
 340      of the locale name from the environment variables (if present) or
 341      the codepage as a number.  */
 342   if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
 343     {
 344       const char *locale;
 345       static char buf[2 + 10 + 1];
 346
 347       locale = getenv ("LC_ALL");
 348       if (locale == NULL || locale[0] == '\0')
 349         {
 350           locale = getenv ("LC_CTYPE");
 351           if (locale == NULL || locale[0] == '\0')
 352             locale = getenv ("LANG");
 353         }
 354       if (locale != NULL && locale[0] != '\0')
 355         {
 356           /* If the locale name contains an encoding after the dot, return
 357              it.  */
 358           const char *dot = strchr (locale, '.');
 359
 360           if (dot != NULL)
 361             {
 362               const char *modifier;
 363
 364               dot++;
 365               /* Look for the possible @... trailer and remove it, if any.  */
 366               modifier = strchr (dot, '@');
 367               if (modifier == NULL)
 368                 return dot;
 369               if (modifier - dot < sizeof (buf))
 370                 {
 371                   memcpy (buf, dot, modifier - dot);
 372                   buf [modifier - dot] = '\0';
 373                   return buf;
 374                 }
 375             }
 376         }
 377
 378       /* Woe32 has a function returning the locale's codepage as a number.  */
 379       sprintf (buf, "CP%u", GetACP ());
 380       codeset = buf;
 381     }
 382 #  endif
 383
 384 # else
 385
 386   /* On old systems which lack it, use setlocale or getenv.  */
 387   const char *locale = NULL;
 388
 389   /* But most old systems don't have a complete set of locales.  Some
 390      (like SunOS 4 or DJGPP) have only the C locale.  Therefore we don't
 391      use setlocale here; it would return "C" when it doesn't support the
 392      locale name the user has set.  */
 393 #  if 0
 394   locale = setlocale (LC_CTYPE, NULL);
 395 #  endif
 396   if (locale == NULL || locale[0] == '\0')
 397     {
 398       locale = getenv ("LC_ALL");
 399       if (locale == NULL || locale[0] == '\0')
 400         {
 401           locale = getenv ("LC_CTYPE");
 402           if (locale == NULL || locale[0] == '\0')
 403             locale = getenv ("LANG");
 404         }
 405     }
 406
 407   /* On some old systems, one used to set locale = "iso8859_1". On others,
 408      you set it to "language_COUNTRY.charset". In any case, we resolve it
 409      through the charset.alias file.  */
 410   codeset = locale;
 411
 412 # endif
 413
 414 #elif defined WIN32_NATIVE
 415
 416   static char buf[2 + 10 + 1];
 417
 418   /* Woe32 has a function returning the locale's codepage as a number.  */
 419   sprintf (buf, "CP%u", GetACP ());
 420   codeset = buf;
 421
 422 #elif defined OS2
 423
 424   const char *locale;
 425   static char buf[2 + 10 + 1];
 426   ULONG cp[3];
 427   ULONG cplen;
 428
 429   /* Allow user to override the codeset, as set in the operating system,
 430      with standard language environment variables.  */
 431   locale = getenv ("LC_ALL");
 432   if (locale == NULL || locale[0] == '\0')
 433     {
 434       locale = getenv ("LC_CTYPE");
 435       if (locale == NULL || locale[0] == '\0')
 436         locale = getenv ("LANG");
 437     }
 438   if (locale != NULL && locale[0] != '\0')
 439     {
 440       /* If the locale name contains an encoding after the dot, return it.  */
 441       const char *dot = strchr (locale, '.');
 442
 443       if (dot != NULL)
 444         {
 445           const char *modifier;
 446
 447           dot++;
 448           /* Look for the possible @... trailer and remove it, if any.  */
 449           modifier = strchr (dot, '@');
 450           if (modifier == NULL)
 451             return dot;
 452           if (modifier - dot < sizeof (buf))
 453             {
 454               memcpy (buf, dot, modifier - dot);
 455               buf [modifier - dot] = '\0';
 456               return buf;
 457             }
 458         }
 459
 460       /* Resolve through the charset.alias file.  */
 461       codeset = locale;
 462     }
 463   else
 464     {
 465       /* OS/2 has a function returning the locale's codepage as a number.  */
 466       if (DosQueryCp (sizeof (cp), cp, &cplen))
 467         codeset = "";
 468       else
 469         {
 470           sprintf (buf, "CP%u", cp[0]);
 471           codeset = buf;
 472         }
 473     }
 474
 475 #endif
 476
 477   if (codeset == NULL)
 478     /* The canonical name cannot be determined.  */
 479     codeset = "";
 480
 481   /* Resolve alias. */
 482   for (aliases = get_charset_aliases ();
 483        *aliases != '\0';
 484        aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
 485     if (strcmp (codeset, aliases) == 0
 486         || (aliases[0] == '*' && aliases[1] == '\0'))
 487       {
 488         codeset = aliases + strlen (aliases) + 1;
 489         break;
 490       }
 491
 492   /* Don't return an empty string.  GNU libc and GNU libiconv interpret
 493      the empty string as denoting "the locale's character encoding",
 494      thus GNU libiconv would call this function a second time.  */
 495   if (codeset[0] == '\0')
 496     codeset = "ASCII";
 497
 498   return codeset;
 499 }