osprey/kg++fe/gnu/intl/localcharset.c

Go to the documentation of this file.

/* Determine a canonical name for the current locale's character encoding.

   Copyright (C) 2000-2001 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA.  */

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

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

#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

#ifndef WIN32
# if HAVE_LANGINFO_CODESET
#  include <langinfo.h>
# else
#  if HAVE_SETLOCALE
#   include <locale.h>
#  endif
# endif
#else /* WIN32 */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif

#include "gettextP.h"

#ifndef DIRECTORY_SEPARATOR
# define DIRECTORY_SEPARATOR '/'
#endif

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

/* GCC LOCAL: Static function prototypes.  */
static const char *get_charset_aliases PARAMS ((void));

/* 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)
    {
#ifndef WIN32
      FILE *fp;
      const char *dir = LIBDIR;
      const char *base = "charset.alias";
      char *file_name;

      /* 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.  */
    int c;
    char buf1[50+1];
    char buf2[50+1];
    char *res_ptr = NULL;
    size_t res_size = 0;
    size_t l1, l2;

    for (;;)
      {
        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);
        if (res_size == 0)
    {
      res_size = l1 + 1 + l2 + 1;
      res_ptr = malloc (res_size + 1);
    }
        else
    {
      res_size += l1 + 1 + l2 + 1;
      res_ptr = realloc (res_ptr, res_size + 1);
    }
        if (res_ptr == NULL)
    {
      /* Out of memory. */
      res_size = 0;
      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 /* 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";
#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.
   GCC LOCAL: Get rid of STATIC nonsense. */

const char *
locale_charset ()
{
  const char *codeset;
  const char *aliases;

#ifndef WIN32

# 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

#else /* WIN32 */

  static char buf[2 + 10 + 1];

  /* Win32 has a function returning the locale's codepage as a number.  */
  sprintf (buf, "CP%u", GetACP ());
  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;
      }

  return codeset;
}

---