| 1 | /* Determine a canonical name for the current locale's character encoding. |
| 2 | |
| 3 | Copyright (C) 2000-2001 Free Software Foundation, Inc. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify it |
| 6 | under the terms of the GNU Library General Public License as published |
| 7 | by the Free Software Foundation; either version 2, or (at your option) |
| 8 | any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Library General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Library General Public |
| 16 | License along with this program; if not, write to the Free Software |
| 17 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
| 18 | USA. */ |
| 19 | |
| 20 | /* Written by Bruno Haible <haible@clisp.cons.org>. */ |
| 21 | |
| 22 | #ifdef HAVE_CONFIG_H |
| 23 | # include <config.h> |
| 24 | #endif |
| 25 | |
| 26 | #if HAVE_STDDEF_H |
| 27 | # include <stddef.h> |
| 28 | #endif |
| 29 | |
| 30 | #include <stdio.h> |
| 31 | #if HAVE_STRING_H |
| 32 | # include <string.h> |
| 33 | #else |
| 34 | # include <strings.h> |
| 35 | #endif |
| 36 | #if HAVE_STDLIB_H |
| 37 | # include <stdlib.h> |
| 38 | #endif |
| 39 | |
| 40 | #if defined _WIN32 || defined __WIN32__ |
| 41 | # undef WIN32 /* avoid warning on mingw32 */ |
| 42 | # define WIN32 |
| 43 | #endif |
| 44 | |
| 45 | #ifndef WIN32 |
| 46 | # if HAVE_LANGINFO_CODESET |
| 47 | # include <langinfo.h> |
| 48 | # else |
| 49 | # if HAVE_SETLOCALE |
| 50 | # include <locale.h> |
| 51 | # endif |
| 52 | # endif |
| 53 | #else /* WIN32 */ |
| 54 | # define WIN32_LEAN_AND_MEAN |
| 55 | # include <windows.h> |
| 56 | #endif |
| 57 | |
| 58 | #ifndef DIRECTORY_SEPARATOR |
| 59 | # define DIRECTORY_SEPARATOR '/' |
| 60 | #endif |
| 61 | |
| 62 | #ifndef ISSLASH |
| 63 | # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR) |
| 64 | #endif |
| 65 | |
| 66 | /* The following static variable is declared 'volatile' to avoid a |
| 67 | possible multithread problem in the function get_charset_aliases. If we |
| 68 | are running in a threaded environment, and if two threads initialize |
| 69 | 'charset_aliases' simultaneously, both will produce the same value, |
| 70 | and everything will be ok if the two assignments to 'charset_aliases' |
| 71 | are atomic. But I don't know what will happen if the two assignments mix. */ |
| 72 | #if __STDC__ != 1 |
| 73 | # define volatile /* empty */ |
| 74 | #endif |
| 75 | /* Pointer to the contents of the charset.alias file, if it has already been |
| 76 | read, else NULL. Its format is: |
| 77 | ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */ |
| 78 | static const char * volatile charset_aliases; |
| 79 | |
| 80 | /* Return a pointer to the contents of the charset.alias file. */ |
| 81 | static const char * |
| 82 | get_charset_aliases () |
| 83 | { |
| 84 | const char *cp; |
| 85 | |
| 86 | cp = charset_aliases; |
| 87 | if (cp == NULL) |
| 88 | { |
| 89 | #ifndef WIN32 |
| 90 | FILE *fp; |
| 91 | const char *dir = LIBDIR; |
| 92 | const char *base = "charset.alias"; |
| 93 | char *file_name; |
| 94 | |
| 95 | /* Concatenate dir and base into freshly allocated file_name. */ |
| 96 | { |
| 97 | size_t dir_len = strlen (dir); |
| 98 | size_t base_len = strlen (base); |
| 99 | int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1])); |
| 100 | file_name = (char *) malloc (dir_len + add_slash + base_len + 1); |
| 101 | if (file_name != NULL) |
| 102 | { |
| 103 | memcpy (file_name, dir, dir_len); |
| 104 | if (add_slash) |
| 105 | file_name[dir_len] = DIRECTORY_SEPARATOR; |
| 106 | memcpy (file_name + dir_len + add_slash, base, base_len + 1); |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | if (file_name == NULL || (fp = fopen (file_name, "r")) == NULL) |
| 111 | /* Out of memory or file not found, treat it as empty. */ |
| 112 | cp = ""; |
| 113 | else |
| 114 | { |
| 115 | /* Parse the file's contents. */ |
| 116 | int c; |
| 117 | char buf1[50+1]; |
| 118 | char buf2[50+1]; |
| 119 | char *res_ptr = NULL; |
| 120 | size_t res_size = 0; |
| 121 | size_t l1, l2; |
| 122 | |
| 123 | for (;;) |
| 124 | { |
| 125 | c = getc (fp); |
| 126 | if (c == EOF) |
| 127 | break; |
| 128 | if (c == '\n' || c == ' ' || c == '\t') |
| 129 | continue; |
| 130 | if (c == '#') |
| 131 | { |
| 132 | /* Skip comment, to end of line. */ |
| 133 | do |
| 134 | c = getc (fp); |
| 135 | while (!(c == EOF || c == '\n')); |
| 136 | if (c == EOF) |
| 137 | break; |
| 138 | continue; |
| 139 | } |
| 140 | ungetc (c, fp); |
| 141 | if (fscanf(fp, "%50s %50s", buf1, buf2) < 2) |
| 142 | break; |
| 143 | l1 = strlen (buf1); |
| 144 | l2 = strlen (buf2); |
| 145 | if (res_size == 0) |
| 146 | { |
| 147 | res_size = l1 + 1 + l2 + 1; |
| 148 | res_ptr = malloc (res_size + 1); |
| 149 | } |
| 150 | else |
| 151 | { |
| 152 | res_size += l1 + 1 + l2 + 1; |
| 153 | res_ptr = realloc (res_ptr, res_size + 1); |
| 154 | } |
| 155 | if (res_ptr == NULL) |
| 156 | { |
| 157 | /* Out of memory. */ |
| 158 | res_size = 0; |
| 159 | break; |
| 160 | } |
| 161 | strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1); |
| 162 | strcpy (res_ptr + res_size - (l2 + 1), buf2); |
| 163 | } |
| 164 | fclose (fp); |
| 165 | if (res_size == 0) |
| 166 | cp = ""; |
| 167 | else |
| 168 | { |
| 169 | *(res_ptr + res_size) = '\0'; |
| 170 | cp = res_ptr; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | if (file_name != NULL) |
| 175 | free (file_name); |
| 176 | |
| 177 | #else /* WIN32 */ |
| 178 | |
| 179 | /* To avoid the troubles of installing a separate file in the same |
| 180 | directory as the DLL and of retrieving the DLL's directory at |
| 181 | runtime, simply inline the aliases here. */ |
| 182 | |
| 183 | cp = "CP936" "\0" "GBK" "\0" |
| 184 | "CP1361" "\0" "JOHAB" "\0"; |
| 185 | #endif |
| 186 | |
| 187 | charset_aliases = cp; |
| 188 | } |
| 189 | |
| 190 | return cp; |
| 191 | } |
| 192 | |
| 193 | /* Determine the current locale's character encoding, and canonicalize it |
| 194 | into one of the canonical names listed in config.charset. |
| 195 | The result must not be freed; it is statically allocated. |
| 196 | If the canonical name cannot be determined, the result is a non-canonical |
| 197 | name. */ |
| 198 | |
| 199 | #ifdef STATIC |
| 200 | STATIC |
| 201 | #endif |
| 202 | const char * |
| 203 | locale_charset () |
| 204 | { |
| 205 | const char *codeset; |
| 206 | const char *aliases; |
| 207 | |
| 208 | #ifndef WIN32 |
| 209 | |
| 210 | # if HAVE_LANGINFO_CODESET |
| 211 | |
| 212 | /* Most systems support nl_langinfo (CODESET) nowadays. */ |
| 213 | codeset = nl_langinfo (CODESET); |
| 214 | |
| 215 | # else |
| 216 | |
| 217 | /* On old systems which lack it, use setlocale or getenv. */ |
| 218 | const char *locale = NULL; |
| 219 | |
| 220 | /* But most old systems don't have a complete set of locales. Some |
| 221 | (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't |
| 222 | use setlocale here; it would return "C" when it doesn't support the |
| 223 | locale name the user has set. */ |
| 224 | # if HAVE_SETLOCALE && 0 |
| 225 | locale = setlocale (LC_CTYPE, NULL); |
| 226 | # endif |
| 227 | if (locale == NULL || locale[0] == '\0') |
| 228 | { |
| 229 | locale = getenv ("LC_ALL"); |
| 230 | if (locale == NULL || locale[0] == '\0') |
| 231 | { |
| 232 | locale = getenv ("LC_CTYPE"); |
| 233 | if (locale == NULL || locale[0] == '\0') |
| 234 | locale = getenv ("LANG"); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | /* On some old systems, one used to set locale = "iso8859_1". On others, |
| 239 | you set it to "language_COUNTRY.charset". In any case, we resolve it |
| 240 | through the charset.alias file. */ |
| 241 | codeset = locale; |
| 242 | |
| 243 | # endif |
| 244 | |
| 245 | #else /* WIN32 */ |
| 246 | |
| 247 | static char buf[2 + 10 + 1]; |
| 248 | |
| 249 | /* Win32 has a function returning the locale's codepage as a number. */ |
| 250 | sprintf (buf, "CP%u", GetACP ()); |
| 251 | codeset = buf; |
| 252 | |
| 253 | #endif |
| 254 | |
| 255 | if (codeset == NULL) |
| 256 | /* The canonical name cannot be determined. */ |
| 257 | codeset = ""; |
| 258 | |
| 259 | /* Resolve alias. */ |
| 260 | for (aliases = get_charset_aliases (); |
| 261 | *aliases != '\0'; |
| 262 | aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1) |
| 263 | if (strcmp (codeset, aliases) == 0 |
| 264 | || (aliases[0] == '*' && aliases[1] == '\0')) |
| 265 | { |
| 266 | codeset = aliases + strlen (aliases) + 1; |
| 267 | break; |
| 268 | } |
| 269 | |
| 270 | return codeset; |
| 271 | } |