1/*
2 * Copyright (C) 1999-2002, 2006 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 * BIG5-HKSCS:1999
23 */
24
25/*
26 * BIG5-HKSCS:1999 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 * Note that some HKSCS characters are not contained in Unicode 3.2
39 * and are therefore best represented as sequences of Unicode characters:
40 *   0x8862  U+00CA U+0304  LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND MACRON
41 *   0x8864  U+00CA U+030C  LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND CARON
42 *   0x88A3  U+00EA U+0304  LATIN SMALL LETTER E WITH CIRCUMFLEX AND MACRON
43 *   0x88A5  U+00EA U+030C  LATIN SMALL LETTER E WITH CIRCUMFLEX AND CARON
44 */
45
46#include "hkscs1999.h"
47#include "flushwc.h"
48
49static int
50big5hkscs1999_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
51{
52  ucs4_t last_wc = conv->istate;
53  if (last_wc) {
54    /* Output the buffered character. */
55    conv->istate = 0;
56    *pwc = last_wc;
57    return 0; /* Don't advance the input pointer. */
58  } else {
59    unsigned char c = *s;
60    /* Code set 0 (ASCII) */
61    if (c < 0x80)
62      return ascii_mbtowc(conv,pwc,s,n);
63    /* Code set 1 (BIG5 extended) */
64    if (c >= 0xa1 && c < 0xff) {
65      if (n < 2)
66        return RET_TOOFEW(0);
67      {
68        unsigned char c2 = s[1];
69        if ((c2 >= 0x40 && c2 < 0x7f) || (c2 >= 0xa1 && c2 < 0xff)) {
70          if (!((c == 0xc6 && c2 >= 0xa1) || c == 0xc7)) {
71            int ret = big5_mbtowc(conv,pwc,s,2);
72            if (ret != RET_ILSEQ)
73              return ret;
74          }
75        }
76      }
77    }
78    {
79      int ret = hkscs1999_mbtowc(conv,pwc,s,n);
80      if (ret != RET_ILSEQ)
81        return ret;
82    }
83    if (c == 0x88) {
84      if (n < 2)
85        return RET_TOOFEW(0);
86      {
87        unsigned char c2 = s[1];
88        if (c2 == 0x62 || c2 == 0x64 || c2 == 0xa3 || c2 == 0xa5) {
89          /* It's a composed character. */
90          ucs4_t wc1 = ((c2 >> 3) << 2) + 0x009a; /* = 0x00ca or 0x00ea */
91          ucs4_t wc2 = ((c2 & 6) << 2) + 0x02fc; /* = 0x0304 or 0x030c */
92          /* We cannot output two Unicode characters at once. So,
93             output the first character and buffer the second one. */
94          *pwc = wc1;
95          conv->istate = wc2;
96          return 2;
97        }
98      }
99    }
100    return RET_ILSEQ;
101  }
102}
103
104#define big5hkscs1999_flushwc normal_flushwc
105
106static int
107big5hkscs1999_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
108{
109  int count = 0;
110  unsigned char last = conv->ostate;
111
112  if (last) {
113    /* last is = 0x66 or = 0xa7. */
114    if (wc == 0x0304 || wc == 0x030c) {
115      /* Output the combined character. */
116      if (n >= 2) {
117        r[0] = 0x88;
118        r[1] = last + ((wc & 24) >> 2) - 4; /* = 0x62 or 0x64 or 0xa3 or 0xa5 */
119        conv->ostate = 0;
120        return 2;
121      } else
122        return RET_TOOSMALL;
123    }
124
125    /* Output the buffered character. */
126    if (n < 2)
127      return RET_TOOSMALL;
128    r[0] = 0x88;
129    r[1] = last;
130    r += 2;
131    count = 2;
132  }
133
134  /* Code set 0 (ASCII) */
135  if (wc < 0x0080) {
136    /* Plain ASCII character. */
137    if (n > count) {
138      r[0] = (unsigned char) wc;
139      conv->ostate = 0;
140      return count+1;
141    } else
142      return RET_TOOSMALL;
143  } else {
144    unsigned char buf[2];
145    int ret;
146
147    /* Code set 1 (BIG5 extended) */
148    ret = big5_wctomb(conv,buf,wc,2);
149    if (ret != RET_ILUNI) {
150      if (ret != 2) abort();
151      if (!((buf[0] == 0xc6 && buf[1] >= 0xa1) || buf[0] == 0xc7)) {
152        if (n >= count+2) {
153          r[0] = buf[0];
154          r[1] = buf[1];
155          conv->ostate = 0;
156          return count+2;
157        } else
158          return RET_TOOSMALL;
159      }
160    }
161    ret = hkscs1999_wctomb(conv,buf,wc,2);
162    if (ret != RET_ILUNI) {
163      if (ret != 2) abort();
164      if ((wc & ~0x0020) == 0x00ca) {
165        /* A possible first character of a multi-character sequence. We have to
166           buffer it. */
167        if (!(buf[0] == 0x88 && (buf[1] == 0x66 || buf[1] == 0xa7))) abort();
168        conv->ostate = buf[1]; /* = 0x66 or = 0xa7 */
169        return count+0;
170      }
171      if (n >= count+2) {
172        r[0] = buf[0];
173        r[1] = buf[1];
174        conv->ostate = 0;
175        return count+2;
176      } else
177        return RET_TOOSMALL;
178    }
179    return RET_ILUNI;
180  }
181}
182
183static int
184big5hkscs1999_reset (conv_t conv, unsigned char *r, int n)
185{
186  unsigned char last = conv->ostate;
187
188  if (last) {
189    if (n < 2)
190      return RET_TOOSMALL;
191    r[0] = 0x88;
192    r[1] = last;
193    /* conv->ostate = 0; will be done by the caller */
194    return 2;
195  } else
196    return 0;
197}
198