diplodocus.org Git - nmh/blob - sbr/check_charset.c

   1
   2 /*
   3  * check_charset.c -- routines for character sets
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9
  10 /*
  11  * Check if we can display a given character set natively.
  12  * We are passed the length of the initial part of the
  13  * string to check, since we want to allow the name of the
  14  * character set to be a substring of a larger string.
  15  */
  16
  17 int
  18 check_charset (char *str, int len)
  19 {
  20     static char *mm_charset = NULL;
  21     static char *alt_charset = NULL;
  22     static int mm_len;
  23     static int alt_len;
  24
  25     /* Cache the name of our default character set */
  26     if (!mm_charset) {
  27         if (!(mm_charset = getenv ("MM_CHARSET")))
  28             mm_charset = "US-ASCII";
  29         mm_len = strlen (mm_charset);
  30
  31         /* US-ASCII is a subset of the ISO-8859-X character sets */
  32         if (!strncasecmp("ISO-8859-", mm_charset, 9)) {
  33             alt_charset = "US-ASCII";
  34             alt_len = strlen (alt_charset);
  35         }
  36     }
  37
  38     /* Check if character set is OK */
  39     if ((len == mm_len) && !strncasecmp(str, mm_charset, mm_len))
  40         return 1;
  41     if (alt_charset && (len == alt_len) && !strncasecmp(str, alt_charset, alt_len))
  42         return 1;
  43
  44     return 0;
  45 }
  46
  47
  48 /*
  49  * Return the name of the character set we are
  50  * using for 8bit text.
  51  */
  52 char *
  53 write_charset_8bit (void)
  54 {
  55     static char *mm_charset = NULL;
  56
  57     /*
  58      * Cache the name of the character set to
  59      * use for 8bit text.
  60      */
  61     if (!mm_charset && !(mm_charset = getenv ("MM_CHARSET")))
  62             mm_charset = "x-unknown";
  63
  64     return mm_charset;
  65 }