Edit
thodg/libiconv/libcharset/lib/localcharset.c
Bruno Haible
- libcharset/lib/localcharset.c
-
/* 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 #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; /* 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. */ #ifdef STATIC STATIC #endif 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; }