272 lines
6.7 KiB
C
272 lines
6.7 KiB
C
/* Determine a canonical name for the current locale's character encoding.
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Copyright (C) 2000-2001 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU Library General Public License as published
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by the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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USA. */
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/* Written by Bruno Haible <haible@clisp.cons.org>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#if HAVE_STDDEF_H
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# include <stddef.h>
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#endif
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#include <stdio.h>
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#if HAVE_STRING_H
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# include <string.h>
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#else
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# include <strings.h>
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#endif
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#if HAVE_STDLIB_H
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# include <stdlib.h>
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#endif
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#if defined _WIN32 || defined __WIN32__
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# undef WIN32 /* avoid warning on mingw32 */
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# define WIN32
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#endif
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#ifndef WIN32
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# if HAVE_LANGINFO_CODESET
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# include <langinfo.h>
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# else
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# if HAVE_SETLOCALE
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# include <locale.h>
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# endif
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# endif
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#else /* WIN32 */
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# define WIN32_LEAN_AND_MEAN
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# include <windows.h>
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#endif
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#ifndef DIRECTORY_SEPARATOR
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# define DIRECTORY_SEPARATOR '/'
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#endif
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#ifndef ISSLASH
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# define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
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#endif
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/* The following static variable is declared 'volatile' to avoid a
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possible multithread problem in the function get_charset_aliases. If we
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are running in a threaded environment, and if two threads initialize
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'charset_aliases' simultaneously, both will produce the same value,
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and everything will be ok if the two assignments to 'charset_aliases'
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are atomic. But I don't know what will happen if the two assignments mix. */
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#if __STDC__ != 1
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# define volatile /* empty */
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#endif
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/* Pointer to the contents of the charset.alias file, if it has already been
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read, else NULL. Its format is:
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ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
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static char * volatile charset_aliases;
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/* Return a pointer to the contents of the charset.alias file. */
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static const char *
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get_charset_aliases ()
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{
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char *cp;
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cp = charset_aliases;
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if (cp == NULL)
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{
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#ifndef WIN32
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FILE *fp;
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const char *dir = LIBDIR;
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const char *base = "charset.alias";
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char *file_name;
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/* Concatenate dir and base into freshly allocated file_name. */
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{
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size_t dir_len = strlen (dir);
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size_t base_len = strlen (base);
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int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
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file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
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if (file_name != NULL)
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{
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memcpy (file_name, dir, dir_len);
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if (add_slash)
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file_name[dir_len] = DIRECTORY_SEPARATOR;
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memcpy (file_name + dir_len + add_slash, base, base_len + 1);
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}
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}
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if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL)
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/* Out of memory or file not found, treat it as empty. */
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cp = "";
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else
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{
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/* Parse the file's contents. */
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int c;
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char buf1[50+1];
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char buf2[50+1];
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char *res_ptr = NULL;
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size_t res_size = 0;
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size_t l1, l2;
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for (;;)
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{
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c = getc (fp);
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if (c == EOF)
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break;
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if (c == '\n' || c == ' ' || c == '\t')
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continue;
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if (c == '#')
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{
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/* Skip comment, to end of line. */
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do
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c = getc (fp);
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while (!(c == EOF || c == '\n'));
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if (c == EOF)
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break;
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continue;
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}
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ungetc (c, fp);
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if (fscanf(fp, "%50s %50s", buf1, buf2) < 2)
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break;
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l1 = strlen (buf1);
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l2 = strlen (buf2);
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if (res_size == 0)
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{
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res_size = l1 + 1 + l2 + 1;
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res_ptr = malloc (res_size + 1);
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}
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else
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{
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res_size += l1 + 1 + l2 + 1;
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res_ptr = realloc (res_ptr, res_size + 1);
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}
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if (res_ptr == NULL)
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{
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/* Out of memory. */
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res_size = 0;
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break;
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}
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strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
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strcpy (res_ptr + res_size - (l2 + 1), buf2);
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}
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fclose (fp);
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if (res_size == 0)
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cp = "";
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else
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{
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*(res_ptr + res_size) = '\0';
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cp = res_ptr;
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}
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}
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if (file_name != NULL)
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free (file_name);
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#else /* WIN32 */
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/* To avoid the troubles of installing a separate file in the same
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directory as the DLL and of retrieving the DLL's directory at
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runtime, simply inline the aliases here. */
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cp = "CP936" "\0" "GBK" "\0"
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"CP1361" "\0" "JOHAB" "\0";
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#endif
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charset_aliases = cp;
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}
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return cp;
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}
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/* Determine the current locale's character encoding, and canonicalize it
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into one of the canonical names listed in config.charset.
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The result must not be freed; it is statically allocated.
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If the canonical name cannot be determined, the result is a non-canonical
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name. */
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#ifdef STATIC
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STATIC
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#endif
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const char *
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locale_charset ()
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{
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const char *codeset;
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const char *aliases;
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#ifndef WIN32
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# if HAVE_LANGINFO_CODESET
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/* Most systems support nl_langinfo (CODESET) nowadays. */
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codeset = nl_langinfo (CODESET);
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# else
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/* On old systems which lack it, use setlocale or getenv. */
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const char *locale = NULL;
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/* But most old systems don't have a complete set of locales. Some
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(like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
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use setlocale here; it would return "C" when it doesn't support the
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locale name the user has set. */
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# if HAVE_SETLOCALE && 0
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locale = setlocale (LC_CTYPE, NULL);
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# endif
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if (locale == NULL || locale[0] == '\0')
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{
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locale = getenv ("LC_ALL");
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if (locale == NULL || locale[0] == '\0')
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{
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locale = getenv ("LC_CTYPE");
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if (locale == NULL || locale[0] == '\0')
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locale = getenv ("LANG");
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}
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}
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/* On some old systems, one used to set locale = "iso8859_1". On others,
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you set it to "language_COUNTRY.charset". In any case, we resolve it
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through the charset.alias file. */
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codeset = locale;
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# endif
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#else /* WIN32 */
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static char buf[2 + 10 + 1];
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/* Win32 has a function returning the locale's codepage as a number. */
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sprintf (buf, "CP%u", GetACP ());
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codeset = buf;
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#endif
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if (codeset == NULL)
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/* The canonical name cannot be determined. */
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codeset = "";
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/* Resolve alias. */
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for (aliases = get_charset_aliases ();
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*aliases != '\0';
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aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
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if (strcmp (codeset, aliases) == 0
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|| (aliases[0] == '*' && aliases[1] == '\0'))
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{
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codeset = aliases + strlen (aliases) + 1;
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break;
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}
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return codeset;
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}
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