missing/langinfo.c

   1 /* -*- c-file-style: "gnu" -*- */
   2 /*
   3  * This is a quick-and-dirty emulator of the nl_langinfo(CODESET)
   4  * function defined in the Single Unix Specification for those systems
   5  * (FreeBSD, etc.) that don't have one yet. It behaves as if it had
   6  * been called after setlocale(LC_CTYPE, ""), that is it looks at
   7  * the locale environment variables.
   8  *
   9  * http://www.opengroup.org/onlinepubs/7908799/xsh/langinfo.h.html
  10  *
  11  * Please extend it as needed and suggest improvements to the author.
  12  * This emulator will hopefully become redundant soon as
  13  * nl_langinfo(CODESET) becomes more widely implemented.
  14  *
  15  * Since the proposed Li18nux encoding name registry is still not mature,
  16  * the output follows the MIME registry where possible:
  17  *
  18  *   http://www.iana.org/assignments/character-sets
  19  *
  20  * A possible autoconf test for the availability of nl_langinfo(CODESET)
  21  * can be found in
  22  *
  23  *   http://www.cl.cam.ac.uk/~mgk25/unicode.html#activate
  24  *
  25  * Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11
  26  * Permission to use, copy, modify, and distribute this software
  27  * for any purpose and without fee is hereby granted. The author
  28  * disclaims all warranties with regard to this software.
  29  *
  30  * Latest version:
  31  *
  32  *   http://www.cl.cam.ac.uk/~mgk25/ucs/langinfo.c
  33  */
  34
  35 #include "ruby/missing.h"
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #if defined _WIN32 || defined __CYGWIN__
  39 #include <windows.h>
  40 #if defined _WIN32 && !defined strncasecmp
  41 #define strncasecmp strnicmp
  42 #endif
  43 #endif
  44 #ifdef HAVE_LANGINFO_H
  45 #include "langinfo.h"
  46 #endif
  47
  48 #define C_CODESET "US-ASCII"     /* Return this as the encoding of the
  49                                   * C/POSIX locale. Could as well one day
  50                                   * become "UTF-8". */
  51
  52 #if defined _WIN32 || defined __CYGWIN__
  53 #define JA_CODESET "Windows-31J"
  54 #else
  55 #define JA_CODESET "EUC-JP"
  56 #endif
  57
  58 #define digit(x) ((x) >= '0' && (x) <= '9')
  59 #define strstart(s, n) (strncasecmp((s), (n), strlen(n)) == 0)
  60
  61 static char buf[16];
  62
  63 const char *
  64 nl_langinfo_codeset(void)
  65 {
  66   const char *l, *p;
  67   int n;
  68
  69   if (((l = getenv("LC_ALL"))   && *l) ||
  70       ((l = getenv("LC_CTYPE")) && *l) ||
  71       ((l = getenv("LANG"))     && *l)) {
  72     /* check standardized locales */
  73     if (!strcmp(l, "C") || !strcmp(l, "POSIX"))
  74       return C_CODESET;
  75     /* check for encoding name fragment */
  76     p = strchr(l, '.');
  77     if (!p++) p = l;
  78     if (strstart(p, "UTF"))
  79         return "UTF-8";
  80     if ((n = 5, strstart(p, "8859-")) || (n = 9, strstart(p, "ISO-8859-"))) {
  81       if (digit(p[n])) {
  82         p += n;
  83         memcpy(buf, "ISO-8859-\0\0", 12);
  84         buf[9] = *p++;
  85         if (digit(*p)) buf[10] = *p++;
  86         return buf;
  87       }
  88     }
  89     if (strstart(p, "KOI8-R")) return "KOI8-R";
  90     if (strstart(p, "KOI8-U")) return "KOI8-U";
  91     if (strstart(p, "620")) return "TIS-620";
  92     if (strstart(p, "2312")) return "GB2312";
  93     if (strstart(p, "HKSCS")) return "Big5HKSCS";   /* no MIME charset */
  94     if (strstart(p, "BIG5")) return "Big5";
  95     if (strstart(p, "GBK")) return "GBK";           /* no MIME charset */
  96     if (strstart(p, "18030")) return "GB18030";     /* no MIME charset */
  97     if (strstart(p, "Shift_JIS") || strstart(p, "SJIS")) return "Windows-31J";
  98     /* check for conclusive modifier */
  99     if (strstart(p, "euro")) return "ISO-8859-15";
 100     /* check for language (and perhaps country) codes */
 101     if (strstart(l, "zh_TW")) return "Big5";
 102     if (strstart(l, "zh_HK")) return "Big5HKSCS";   /* no MIME charset */
 103     if (strstart(l, "zh")) return "GB2312";
 104     if (strstart(l, "ja")) return JA_CODESET;
 105     if (strstart(l, "ko")) return "EUC-KR";
 106     if (strstart(l, "ru")) return "KOI8-R";
 107     if (strstart(l, "uk")) return "KOI8-U";
 108     if (strstart(l, "pl") || strstart(l, "hr") ||
 109         strstart(l, "hu") || strstart(l, "cs") ||
 110         strstart(l, "sk") || strstart(l, "sl")) return "ISO-8859-2";
 111     if (strstart(l, "eo") || strstart(l, "mt")) return "ISO-8859-3";
 112     if (strstart(l, "el")) return "ISO-8859-7";
 113     if (strstart(l, "he")) return "ISO-8859-8";
 114     if (strstart(l, "tr")) return "ISO-8859-9";
 115     if (strstart(l, "th")) return "TIS-620";      /* or ISO-8859-11 */
 116     if (strstart(l, "lt")) return "ISO-8859-13";
 117     if (strstart(l, "cy")) return "ISO-8859-14";
 118     if (strstart(l, "ro")) return "ISO-8859-2";   /* or ISO-8859-16 */
 119     if (strstart(l, "am") || strstart(l, "vi")) return "UTF-8";
 120     /* Send me further rules if you like, but don't forget that we are
 121      * *only* interested in locale naming conventions on platforms
 122      * that do not already provide an nl_langinfo(CODESET) implementation. */
 123   }
 124   return NULL;
 125 }
 126
 127 #ifdef HAVE_LANGINFO_H
 128 char *nl_langinfo(nl_item item)
 129 {
 130   const char *codeset;
 131   if (item != CODESET)
 132     return NULL;
 133   codeset = nl_langinfo_codeset();
 134   if (!codeset) codeset = C_CODESET;
 135   return (char *)codeset;
 136 }
 137 #endif
 138
 139 /* For a demo, compile with "gcc -W -Wall -o langinfo -D TEST langinfo.c" */
 140
 141 #ifdef TEST
 142 #include <stdio.h>
 143 int main(void)
 144 {
 145   printf("%s\n", nl_langinfo(CODESET));
 146   return 0;
 147 }
 148 #endif