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

   1
   2 /*
   3  * check_charset.c -- routines for character sets
   4  *
   5  * $Id$
   6  *
   7  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 #include <h/mh.h>
  13
  14 /*
  15  * Check if we can display a given character set natively.
  16  * We are passed the length of the initial part of the
  17  * string to check, since we want to allow the name of the
  18  * character set to be a substring of a larger string.
  19  */
  20
  21 int
  22 check_charset (char *str, int len)
  23 {
  24     static char *mm_charset = NULL;
  25     static char *alt_charset = NULL;
  26     static int mm_len;
  27     static int alt_len;
  28
  29     /* Cache the name of our default character set */
  30     if (!mm_charset) {
  31         if (!(mm_charset = getenv ("MM_CHARSET")))
  32             mm_charset = "US-ASCII";
  33         mm_len = strlen (mm_charset);
  34
  35         /* US-ASCII is a subset of the ISO-8859-X character sets */
  36         if (!strncasecmp("ISO-8859-", mm_charset, 9)) {
  37             alt_charset = "US-ASCII";
  38             alt_len = strlen (alt_charset);
  39         }
  40     }
  41
  42     /* Check if character set is OK */
  43     if ((len == mm_len) && !strncasecmp(str, mm_charset, mm_len))
  44         return 1;
  45     if (alt_charset && (len == alt_len) && !strncasecmp(str, alt_charset, alt_len))
  46         return 1;
  47
  48     return 0;
  49 }
  50
  51
  52 /*
  53  * Return the name of the character set we are
  54  * using for 8bit text.
  55  */
  56 char *
  57 write_charset_8bit (void)
  58 {
  59     static char *mm_charset = NULL;
  60
  61     /*
  62      * Cache the name of the character set to
  63      * use for 8bit text.
  64      */
  65     if (!mm_charset && !(mm_charset = getenv ("MM_CHARSET")))
  66             mm_charset = "x-unknown";
  67
  68     return mm_charset;
  69 }