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

   Copyright (C) 2000-2002 Free Software Foundation, Inc.

   Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

   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 <bruno@clisp.org>.  */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <glibconfig.h>

#ifdef __SYMBIAN32__

#ifndef LIBDIR

#define LIBDIR "c:\\sys\\bin" 

#endif /* LIBDIR */

#endif /* __SYMBIAN32__ */

#if defined G_PLATFORM_WIN32

/* Want to use Win32-specific code in this file also on Cygwin */

# define _WIN32 1		

#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__ ) && (!defined __SYMBIAN32__)

# 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

#ifdef __SYMBIAN32__

#include <glib_wsd.h>

#endif /* __SYMBIAN32__ */

#if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__

  /* Win32, 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

#ifdef HAVE_GETC_UNLOCKED

# undef getc

# define getc getc_unlocked

#endif

#ifdef __cplusplus

/* When compiling with "gcc -x c++", produce a function with C linkage.  */

extern "C" const char * locale_charset (void);

#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'  */

#if EMULATOR

PLS(charset_aliases,localcharset,const char * volatile)

#define charset_aliases (*FUNCTION_NAME(charset_aliases,localcharset)())

#else

static const char * volatile charset_aliases;

#endif /* EMULATOR */

/* Return a pointer to the contents of the charset.alias file.  */

const char *

_g_locale_get_charset_aliases (void)

{

  const char *cp;

  cp = charset_aliases;

  if (cp == NULL)

    {

#if !defined WIN32

      FILE *fp;

      const char *dir = getenv ("LIBCHARSET_ALIAS_DIR");

      const char *base = "charset.alias";

      char *file_name;

      if (dir == NULL)

	dir = 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.  */

	  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 = (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;

		  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

      /* 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.  */

# if defined WIN32

      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.  */

const char *

_g_locale_charset_raw (void)

{

  const char *codeset;

#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

  return codeset;

}

#ifdef STATIC

STATIC

#endif

const char *

_g_locale_charset_unalias (const char *codeset)

{

  const char *aliases;

  if (codeset == NULL)

    /* The canonical name cannot be determined.  */

    codeset = "";

  /* Resolve alias. */

  for (aliases = _g_locale_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;

}