1/*
2 * Copyright (C) 1999-2001 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 * BIG5-HKSCS
23 */
24
25/*
26 * BIG5-HKSCS 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
45static int
46big5hkscs_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
70static int
71big5hkscs_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_ILUNI)
79    return ret;
80
81  /* Code set 1 (BIG5 extended) */
82  ret = big5_wctomb(conv,buf,wc,2);
83  if (ret != RET_ILUNI) {
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}
95