1/*
2 * Copyright (C) 1999-2002 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 * SHIFT_JIS
23 */
24
25/*
26   Conversion between SJIS codes (s1,s2) and JISX0208 codes (c1,c2):
27   Example. (s1,s2) = 0x8140, (c1,c2) = 0x2121.
28   0x81 <= s1 <= 0x9F || 0xE0 <= s1 <= 0xEA,
29   0x40 <= s2 <= 0x7E || 0x80 <= s2 <= 0xFC,
30   0x21 <= c1 <= 0x74, 0x21 <= c2 <= 0x7E.
31   Invariant:
32     94*2*(s1 < 0xE0 ? s1-0x81 : s1-0xC1) + (s2 < 0x80 ? s2-0x40 : s2-0x41)
33     = 94*(c1-0x21)+(c2-0x21)
34   Conversion (s1,s2) -> (c1,c2):
35     t1 := (s1 < 0xE0 ? s1-0x81 : s1-0xC1)
36     t2 := (s2 < 0x80 ? s2-0x40 : s2-0x41)
37     c1 := 2*t1 + (t2 < 0x5E ? 0 : 1) + 0x21
38     c2 := (t2 < 0x5E ? t2 : t2-0x5E) + 0x21
39   Conversion (c1,c2) -> (s1,s2):
40     t1 := (c1 - 0x21) >> 1
41     t2 := ((c1 - 0x21) & 1) * 0x5E + (c2 - 0x21)
42     s1 := (t1 < 0x1F ? t1+0x81 : t1+0xC1)
43     s2 := (t2 < 0x3F ? t2+0x40 : t2+0x41)
44 */
45
46static int
47sjis_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
48{
49  unsigned char c = *s;
50  if (c < 0x80 || (c >= 0xa1 && c <= 0xdf))
51    return jisx0201_mbtowc(conv,pwc,s,n);
52  else {
53    unsigned char s1, s2;
54    s1 = c;
55    if ((s1 >= 0x81 && s1 <= 0x9f) || (s1 >= 0xe0 && s1 <= 0xea)) {
56      if (n < 2)
57        return RET_TOOFEW(0);
58      s2 = s[1];
59      if ((s2 >= 0x40 && s2 <= 0x7e) || (s2 >= 0x80 && s2 <= 0xfc)) {
60        unsigned char t1 = (s1 < 0xe0 ? s1-0x81 : s1-0xc1);
61        unsigned char t2 = (s2 < 0x80 ? s2-0x40 : s2-0x41);
62        unsigned char buf[2];
63        buf[0] = 2*t1 + (t2 < 0x5e ? 0 : 1) + 0x21;
64        buf[1] = (t2 < 0x5e ? t2 : t2-0x5e) + 0x21;
65        return jisx0208_mbtowc(conv,pwc,buf,2);
66      }
67    } else if (s1 >= 0xf0 && s1 <= 0xf9) {
68      /* User-defined range. See
69       * Ken Lunde's "CJKV Information Processing", table 4-66, p. 206. */
70      if (n < 2)
71        return RET_TOOFEW(0);
72      s2 = s[1];
73      if ((s2 >= 0x40 && s2 <= 0x7e) || (s2 >= 0x80 && s2 <= 0xfc)) {
74        *pwc = 0xe000 + 188*(s1 - 0xf0) + (s2 < 0x80 ? s2-0x40 : s2-0x41);
75        return 2;
76      }
77    }
78    return RET_ILSEQ;
79  }
80}
81
82static int
83sjis_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
84{
85  unsigned char buf[2];
86  int ret;
87
88  /* Try JIS X 0201-1976. */
89  ret = jisx0201_wctomb(conv,buf,wc,1);
90  if (ret != RET_ILUNI) {
91    unsigned char c;
92    if (ret != 1) abort();
93    c = buf[0];
94    if (c < 0x80 || (c >= 0xa1 && c <= 0xdf)) {
95      r[0] = c;
96      return 1;
97    }
98  }
99
100  /* Try JIS X 0208-1990. */
101  ret = jisx0208_wctomb(conv,buf,wc,2);
102  if (ret != RET_ILUNI) {
103    unsigned char c1, c2;
104    if (ret != 2) abort();
105    if (n < 2)
106      return RET_TOOSMALL;
107    c1 = buf[0];
108    c2 = buf[1];
109    if ((c1 >= 0x21 && c1 <= 0x74) && (c2 >= 0x21 && c2 <= 0x7e)) {
110      unsigned char t1 = (c1 - 0x21) >> 1;
111      unsigned char t2 = (((c1 - 0x21) & 1) ? 0x5e : 0) + (c2 - 0x21);
112      r[0] = (t1 < 0x1f ? t1+0x81 : t1+0xc1);
113      r[1] = (t2 < 0x3f ? t2+0x40 : t2+0x41);
114      return 2;
115    }
116  }
117
118  /* User-defined range. See
119   * Ken Lunde's "CJKV Information Processing", table 4-66, p. 206. */
120  if (wc >= 0xe000 && wc < 0xe758) {
121    unsigned char c1, c2;
122    if (n < 2)
123      return RET_TOOSMALL;
124    c1 = (unsigned int) (wc - 0xe000) / 188;
125    c2 = (unsigned int) (wc - 0xe000) % 188;
126    r[0] = c1+0xf0;
127    r[1] = (c2 < 0x3f ? c2+0x40 : c2+0x41);
128    return 2;
129  }
130
131  return RET_ILUNI;
132}
133