lib/big5hkscs.h

   1 /*
   2  * Copyright (C) 1999-2000 Free Software Foundation, Inc.
   3  * This file is part of the GNU LIBICONV Library.
   4  *
   5  * The GNU LIBICONV Library is free software; you can redistribute it
   6  * and/or modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * The GNU LIBICONV Library is distributed in the hope that it will be
  11  * useful, 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 the GNU LIBICONV Library; see the file COPYING.LIB.
  17  * If not, write to the Free Software Foundation, Inc., 59 Temple Place -
  18  * Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 /*
  22  * BIG5HKSCS
  23  */
  24
  25 /*
  26  * BIG5HKSCS can be downloaded from
  27  *   http://www.info.gov.hk/digital21/eng/hkscs/download.html
  28  *   http://www.info.gov.hk/digital21/eng/hkscs/index.html
  29  *
  30  * It extends BIG5 (without the rows 0xC6..0xC7) through the ranges
  31  *
  32  *   0x{88..8D}{40..7E,A1..FE}      641 characters
  33  *   0x{8E..A0}{40..7E,A1..FE}     2898 characters
  34  *   0x{C6..C8}{40..7E,A1..FE}      359 characters
  35  *   0xF9{D6..FE}                    41 characters
  36  *   0x{FA..FE}{40..7E,A1..FE}      763 characters
  37  *
  38  * It thereby introduces an irreversible mapping
  39  *   0x8BF8   0x9F9C
  40  *   0xC074   0x9F9C
  41  */
  42
  43 #include "hkscs.h"
  44
  45 static int
  46 big5hkscs_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
  47 {
  48   unsigned char c = *s;
  49   /* Code set 0 (ASCII) */
  50   if (c < 0x80)
  51     return ascii_mbtowc(conv,pwc,s,n);
  52   /* Code set 1 (BIG5 extended) */
  53   if (c >= 0xa1 && c < 0xff) {
  54     if (n < 2)
  55       return RET_TOOFEW(0);
  56     {
  57       unsigned char c2 = s[1];
  58       if ((c2 >= 0x40 && c2 < 0x7f) || (c2 >= 0xa1 && c2 < 0xff)) {
  59         if (!((c == 0xc6 && c2 >= 0xa1) || c == 0xc7)) {
  60           int ret = big5_mbtowc(conv,pwc,s,2);
  61           if (ret != RET_ILSEQ)
  62             return ret;
  63         }
  64       }
  65     }
  66   }
  67   return hkscs_mbtowc(conv,pwc,s,n);
  68 }
  69
  70 static int
  71 big5hkscs_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
  72 {
  73   unsigned char buf[2];
  74   int ret;
  75
  76   /* Code set 0 (ASCII) */
  77   ret = ascii_wctomb(conv,r,wc,n);
  78   if (ret != RET_ILSEQ)
  79     return ret;
  80
  81   /* Code set 1 (BIG5 extended) */
  82   ret = big5_wctomb(conv,buf,wc,2);
  83   if (ret != RET_ILSEQ) {
  84     if (ret != 2) abort();
  85     if (!((buf[0] == 0xc6 && buf[1] >= 0xa1) || buf[0] == 0xc7)) {
  86       if (n < 2)
  87         return RET_TOOSMALL;
  88       r[0] = buf[0];
  89       r[1] = buf[1];
  90       return 2;
  91     }
  92   }
  93   return hkscs_wctomb(conv,r,wc,n);
  94 }