src/lib-roff/localcharset.c

   1 /*@ Determine a canonical name for the current locale's character encoding.
   2  *
   3  * Copyright (c) 2014 - 2017 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
   4  *
   5  *    Copyright (C) 2000-2006, 2008 Free Software Foundation, Inc.
   6  *
   7  *    This program 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 2, or (at your option)
  10  *    any later version.
  11  *
  12  *    This program 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 along
  18  *    with this program; if not, write to the Free Software Foundation,
  19  *    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  */
  21
  22 /* Written by Bruno Haible <bruno@clisp.org>.  */
  23
  24 #include "config.h"
  25
  26 /* Specification.  */
  27 #include "localcharset.h"
  28
  29 #include <stddef.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #if defined _WIN32 || defined __WIN32__
  35 # define WIN32_NATIVE
  36 #endif
  37
  38 #if defined __EMX__
  39 /* Assume EMX program runs on OS/2, even if compiled under DOS.  */
  40 # ifndef OS2
  41 #  define OS2
  42 # endif
  43 #endif
  44
  45 #if !defined WIN32_NATIVE
  46 # if HAVE_LANGINFO_CODESET
  47 #  include <langinfo.h>
  48 # else
  49 #  if 0 /* see comment below */
  50 #   include <locale.h>
  51 #  endif
  52 # endif
  53 # ifdef __CYGWIN__
  54 #  define WIN32_LEAN_AND_MEAN
  55 #  include <windows.h>
  56 # endif
  57 #elif defined WIN32_NATIVE
  58 # define WIN32_LEAN_AND_MEAN
  59 # include <windows.h>
  60 #endif
  61 #if defined OS2
  62 # define INCL_DOS
  63 # include <os2.h>
  64 #endif
  65
  66 #if ENABLE_RELOCATABLE
  67 # include "relocatable.h"
  68 #else
  69 # define relocate(pathname) (pathname)
  70 #endif
  71
  72 /* Get LIBDIR.  */
  73 #ifndef LIBDIR
  74 # include "configmake.h"
  75 #endif
  76
  77 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
  78   /* Win32, Cygwin, 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 #if HAVE_DECL_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 (void)
 112 {
 113   const char *cp;
 114
 115   cp = charset_aliases;
 116   if (cp == NULL)
 117     {
 118 #if !(defined VMS || defined WIN32_NATIVE || defined __CYGWIN__)
 119       FILE *fp;
 120       const char *dir;
 121       const char *base = "charset.alias";
 122       char *file_name;
 123
 124       /* Make it possible to override the charset.alias location.  This is
 125          necessary for running the testsuite before "make install".  */
 126       dir = getenv ("CHARSETALIASDIR");
 127       if (dir == NULL || dir[0] == '\0')
 128         dir = relocate (LIBDIR);
 129
 130       /* Concatenate dir and base into freshly allocated file_name.  */
 131       {
 132         size_t dir_len = strlen (dir);
 133         size_t base_len = strlen (base);
 134         int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
 135         file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
 136         if (file_name != NULL)
 137           {
 138             memcpy (file_name, dir, dir_len);
 139             if (add_slash)
 140               file_name[dir_len] = DIRECTORY_SEPARATOR;
 141             memcpy (file_name + dir_len + add_slash, base, base_len + 1);
 142           }
 143       }
 144
 145       if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
 146         /* Out of memory or file not found, treat it as empty.  */
 147         cp = "";
 148       else
 149         {
 150           /* Parse the file's contents.  */
 151           char *res_ptr = NULL;
 152           size_t res_size = 0;
 153
 154           for (;;)
 155             {
 156               int c;
 157               char buf1[50+1];
 158               char buf2[50+1];
 159               size_t l1, l2;
 160               char *old_res_ptr;
 161
 162               c = getc (fp);
 163               if (c == EOF)
 164                 break;
 165               if (c == '\n' || c == ' ' || c == '\t')
 166                 continue;
 167               if (c == '#')
 168                 {
 169                   /* Skip comment, to end of line.  */
 170                   do
 171                     c = getc (fp);
 172                   while (!(c == EOF || c == '\n'));
 173                   if (c == EOF)
 174                     break;
 175                   continue;
 176                 }
 177               ungetc (c, fp);
 178               if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
 179                 break;
 180               l1 = strlen (buf1);
 181               l2 = strlen (buf2);
 182               old_res_ptr = res_ptr;
 183               if (res_size == 0)
 184                 {
 185                   res_size = l1 + 1 + l2 + 1;
 186                   res_ptr = (char *) malloc (res_size + 1);
 187                 }
 188               else
 189                 {
 190                   res_size += l1 + 1 + l2 + 1;
 191                   res_ptr = (char *) realloc (res_ptr, res_size + 1);
 192                 }
 193               if (res_ptr == NULL)
 194                 {
 195                   /* Out of memory. */
 196                   res_size = 0;
 197                   if (old_res_ptr != NULL)
 198                     free (old_res_ptr);
 199                   break;
 200                 }
 201               strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
 202               strcpy (res_ptr + res_size - (l2 + 1), buf2);
 203             }
 204           fclose (fp);
 205           if (res_size == 0)
 206             cp = "";
 207           else
 208             {
 209               *(res_ptr + res_size) = '\0';
 210               cp = res_ptr;
 211             }
 212         }
 213
 214       if (file_name != NULL)
 215         free (file_name);
 216
 217 #else
 218
 219 # if defined VMS
 220       /* To avoid the troubles of an extra file charset.alias_vms in the
 221          sources of many GNU packages, simply inline the aliases here.  */
 222       /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
 223          "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
 224          section 10.7 "Handling Different Character Sets".  */
 225       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 226            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 227            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 228            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 229            "ISO8859-8" "\0" "ISO-8859-8" "\0"
 230            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 231            /* Japanese */
 232            "eucJP" "\0" "EUC-JP" "\0"
 233            "SJIS" "\0" "SHIFT_JIS" "\0"
 234            "DECKANJI" "\0" "DEC-KANJI" "\0"
 235            "SDECKANJI" "\0" "EUC-JP" "\0"
 236            /* Chinese */
 237            "eucTW" "\0" "EUC-TW" "\0"
 238            "DECHANYU" "\0" "DEC-HANYU" "\0"
 239            "DECHANZI" "\0" "GB2312" "\0"
 240            /* Korean */
 241            "DECKOREAN" "\0" "EUC-KR" "\0";
 242 # endif
 243
 244 # if defined WIN32_NATIVE || defined __CYGWIN__
 245       /* To avoid the troubles of installing a separate file in the same
 246          directory as the DLL and of retrieving the DLL's directory at
 247          runtime, simply inline the aliases here.  */
 248
 249       cp = "CP936" "\0" "GBK" "\0"
 250            "CP1361" "\0" "JOHAB" "\0"
 251            "CP20127" "\0" "ASCII" "\0"
 252            "CP20866" "\0" "KOI8-R" "\0"
 253            "CP20936" "\0" "GB2312" "\0"
 254            "CP21866" "\0" "KOI8-RU" "\0"
 255            "CP28591" "\0" "ISO-8859-1" "\0"
 256            "CP28592" "\0" "ISO-8859-2" "\0"
 257            "CP28593" "\0" "ISO-8859-3" "\0"
 258            "CP28594" "\0" "ISO-8859-4" "\0"
 259            "CP28595" "\0" "ISO-8859-5" "\0"
 260            "CP28596" "\0" "ISO-8859-6" "\0"
 261            "CP28597" "\0" "ISO-8859-7" "\0"
 262            "CP28598" "\0" "ISO-8859-8" "\0"
 263            "CP28599" "\0" "ISO-8859-9" "\0"
 264            "CP28605" "\0" "ISO-8859-15" "\0"
 265            "CP38598" "\0" "ISO-8859-8" "\0"
 266            "CP51932" "\0" "EUC-JP" "\0"
 267            "CP51936" "\0" "GB2312" "\0"
 268            "CP51949" "\0" "EUC-KR" "\0"
 269            "CP51950" "\0" "EUC-TW" "\0"
 270            "CP54936" "\0" "GB18030" "\0"
 271            "CP65001" "\0" "UTF-8" "\0";
 272 # endif
 273 #endif
 274
 275       charset_aliases = cp;
 276     }
 277
 278   return cp;
 279 }
 280
 281 /* Determine the current locale's character encoding, and canonicalize it
 282    into one of the canonical names listed in config.charset.
 283    The result must not be freed; it is statically allocated.
 284    If the canonical name cannot be determined, the result is a non-canonical
 285    name.  */
 286
 287 #ifdef STATIC
 288 STATIC
 289 #endif
 290 const char *
 291 locale_charset (void)
 292 {
 293   const char *codeset;
 294   const char *aliases;
 295
 296 #if !(defined WIN32_NATIVE || defined OS2)
 297
 298 # if HAVE_LANGINFO_CODESET
 299
 300   /* Most systems support nl_langinfo (CODESET) nowadays.  */
 301   codeset = nl_langinfo (CODESET);
 302
 303 #  ifdef __CYGWIN__
 304   /* Cygwin 2006 does not have locales.  nl_langinfo (CODESET) always
 305      returns "US-ASCII".  As long as this is not fixed, return the suffix
 306      of the locale name from the environment variables (if present) or
 307      the codepage as a number.  */
 308   if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
 309     {
 310       const char *locale;
 311       static char buf[2 + 10 + 1];
 312
 313       locale = getenv ("LC_ALL");
 314       if (locale == NULL || locale[0] == '\0')
 315         {
 316           locale = getenv ("LC_CTYPE");
 317           if (locale == NULL || locale[0] == '\0')
 318             locale = getenv ("LANG");
 319         }
 320       if (locale != NULL && locale[0] != '\0')
 321         {
 322           /* If the locale name contains an encoding after the dot, return
 323              it.  */
 324           const char *dot = strchr (locale, '.');
 325
 326           if (dot != NULL)
 327             {
 328               const char *modifier;
 329
 330               dot++;
 331               /* Look for the possible @... trailer and remove it, if any.  */
 332               modifier = strchr (dot, '@');
 333               if (modifier == NULL)
 334                 return dot;
 335               if (modifier - dot < sizeof (buf))
 336                 {
 337                   memcpy (buf, dot, modifier - dot);
 338                   buf [modifier - dot] = '\0';
 339                   return buf;
 340                 }
 341             }
 342         }
 343
 344       /* Woe32 has a function returning the locale's codepage as a number.  */
 345       sprintf (buf, "CP%u", GetACP ());
 346       codeset = buf;
 347     }
 348 #  endif
 349
 350 # else
 351
 352   /* On old systems which lack it, use setlocale or getenv.  */
 353   const char *locale = NULL;
 354
 355   /* But most old systems don't have a complete set of locales.  Some
 356      (like SunOS 4 or DJGPP) have only the C locale.  Therefore we don't
 357      use setlocale here; it would return "C" when it doesn't support the
 358      locale name the user has set.  */
 359 #  if 0
 360   locale = setlocale (LC_CTYPE, NULL);
 361 #  endif
 362   if (locale == NULL || locale[0] == '\0')
 363     {
 364       locale = getenv ("LC_ALL");
 365       if (locale == NULL || locale[0] == '\0')
 366         {
 367           locale = getenv ("LC_CTYPE");
 368           if (locale == NULL || locale[0] == '\0')
 369             locale = getenv ("LANG");
 370         }
 371     }
 372
 373   /* On some old systems, one used to set locale = "iso8859_1". On others,
 374      you set it to "language_COUNTRY.charset". In any case, we resolve it
 375      through the charset.alias file.  */
 376   codeset = locale;
 377
 378 # endif
 379
 380 #elif defined WIN32_NATIVE
 381
 382   static char buf[2 + 10 + 1];
 383
 384   /* Woe32 has a function returning the locale's codepage as a number.  */
 385   sprintf (buf, "CP%u", GetACP ());
 386   codeset = buf;
 387
 388 #elif defined OS2
 389
 390   const char *locale;
 391   static char buf[2 + 10 + 1];
 392   ULONG cp[3];
 393   ULONG cplen;
 394
 395   /* Allow user to override the codeset, as set in the operating system,
 396      with standard language environment variables.  */
 397   locale = getenv ("LC_ALL");
 398   if (locale == NULL || locale[0] == '\0')
 399     {
 400       locale = getenv ("LC_CTYPE");
 401       if (locale == NULL || locale[0] == '\0')
 402         locale = getenv ("LANG");
 403     }
 404   if (locale != NULL && locale[0] != '\0')
 405     {
 406       /* If the locale name contains an encoding after the dot, return it.  */
 407       const char *dot = strchr (locale, '.');
 408
 409       if (dot != NULL)
 410         {
 411           const char *modifier;
 412
 413           dot++;
 414           /* Look for the possible @... trailer and remove it, if any.  */
 415           modifier = strchr (dot, '@');
 416           if (modifier == NULL)
 417             return dot;
 418           if (modifier - dot < sizeof (buf))
 419             {
 420               memcpy (buf, dot, modifier - dot);
 421               buf [modifier - dot] = '\0';
 422               return buf;
 423             }
 424         }
 425
 426       /* Resolve through the charset.alias file.  */
 427       codeset = locale;
 428     }
 429   else
 430     {
 431       /* OS/2 has a function returning the locale's codepage as a number.  */
 432       if (DosQueryCp (sizeof (cp), cp, &cplen))
 433         codeset = "";
 434       else
 435         {
 436           sprintf (buf, "CP%u", cp[0]);
 437           codeset = buf;
 438         }
 439     }
 440
 441 #endif
 442
 443   if (codeset == NULL)
 444     /* The canonical name cannot be determined.  */
 445     codeset = "";
 446
 447   /* Resolve alias. */
 448   for (aliases = get_charset_aliases ();
 449        *aliases != '\0';
 450        aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
 451     if (strcmp (codeset, aliases) == 0
 452         || (aliases[0] == '*' && aliases[1] == '\0'))
 453       {
 454         codeset = aliases + strlen (aliases) + 1;
 455         break;
 456       }
 457
 458   /* Don't return an empty string.  GNU libc and GNU libiconv interpret
 459      the empty string as denoting "the locale's character encoding",
 460      thus GNU libiconv would call this function a second time.  */
 461   if (codeset[0] == '\0')
 462     codeset = "ASCII";
 463
 464   return codeset;
 465 }
 466
 467 // s-it2-mode