1/*
2 * Copyright (C) 2005 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., 51 Franklin Street,
18 * Fifth Floor, Boston, MA 02110-1301, USA.
19 */
20
21/*
22 * CP936
23 */
24
25/*
26 * The IANA has CP936 as an alias of GBK. But GBK is an official Chinese
27 * specification, whereas CP936 is de-facto maintained by Microsoft. And,
28 * of course, Microsoft modified CP936 since 1999.
29 *
30 * The differences from GBK are:
31 *
32 * 1. A single character:
33 *
34 *    code   CP936.TXT
35 *    0x80   0x20AC # EURO SIGN
36 *
37 * Some variants of CP936 (in JDK, Windows-2000, ICU) also add:
38 *
39 * 2. Private area mappings:
40 *
41 *              code                 Unicode
42 *    0x{A1..A2}{40..7E,80..A0}  U+E4C6..U+E585
43 *    0x{AA..AF,F8..FE}{A1..FE}  U+E000..U+E4C5
44 *
45 * We add them too because, although there are backward compatibility problems
46 * when a character from a private area is moved to an official Unicode code
47 * point, they are useful for some people in practice.
48 */
49
50static int
51cp936_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
52{
53  /* Try GBK first. */
54  {
55    int ret = ces_gbk_mbtowc(conv,pwc,s,n);
56    if (ret != RET_ILSEQ)
57      return ret;
58  }
59  /* Then handle the additional mappings. */
60  {
61    unsigned char c = *s;
62    if (c == 0x80) {
63      *pwc = 0x20ac;
64      return 1;
65    }
66    /* User-defined characters */
67    if (c >= 0xa1 && c <= 0xa2) {
68      if (n < 2)
69        return RET_TOOFEW(0);
70      {
71        unsigned char c2 = s[1];
72        if ((c2 >= 0x40 && c2 < 0x7f) || (c2 >= 0x80 && c2 < 0xa1)) {
73          *pwc = 0xe4c6 + 96 * (c - 0xa1) + (c2 - (c2 >= 0x80 ? 0x41 : 0x40));
74          return 2;
75        }
76      }
77    } else if ((c >= 0xaa && c < 0xb0) || (c >= 0xf8 && c < 0xff)) {
78      if (n < 2)
79        return RET_TOOFEW(0);
80      {
81        unsigned char c2 = s[1];
82        if (c2 >= 0xa1 && c2 < 0xff) {
83          *pwc = 0xe000 + 94 * (c - (c >= 0xf8 ? 0xf2 : 0xaa)) + (c2 - 0xa1);
84          return 2;
85        }
86      }
87    }
88  }
89  return RET_ILSEQ;
90}
91
92static int
93cp936_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
94{
95  /* Try GBK first. */
96  {
97    int ret = ces_gbk_wctomb(conv,r,wc,n);
98    if (ret != RET_ILUNI)
99      return ret;
100  }
101  /* Then handle the additional mappings. */
102  if (wc >= 0xe000 && wc < 0xe586) {
103    /* User-defined characters */
104    if (n < 2)
105      return RET_TOOFEW(0);
106    if (wc < 0xe4c6) {
107      unsigned int i = wc - 0xe000;
108      unsigned int c1 = i / 94;
109      unsigned int c2 = i % 94;
110      r[0] = c1 + (c1 < 6 ? 0xaa : 0xf2);
111      r[1] = c2 + 0xa1;
112      return 2;
113    } else {
114      unsigned int i = wc - 0xe4c6;
115      unsigned int c1 = i / 96;
116      unsigned int c2 = i % 96;
117      r[0] = c1 + 0xa1;
118      r[1] = c2 + (c2 < 0x3f ? 0x40 : 0x41);
119      return 2;
120    }
121  } else if (wc == 0x20ac) {
122    r[0] = 0x80;
123    return 1;
124  }
125  return RET_ILUNI;
126}
127