1/*
2 * Copyright (C) 1999-2001, 2008 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 * ISO-2022-KR
23 */
24
25/* Specification: RFC 1557 */
26
27/* Note: CJK.INF says the SO designator needs to appear only once at the
28   beginning of a text, but to decrease the risk of ambiguities, when
29   producing ISO-2022-KR, we repeat the designator in every line containing
30   SO characters. RFC 1557 does not mandate this. */
31
32#define ESC 0x1b
33#define SO  0x0e
34#define SI  0x0f
35
36/*
37 * The state is composed of one of the following values
38 */
39#define STATE_ASCII          0
40#define STATE_TWOBYTE        1
41/*
42 * and one of the following values, << 8
43 */
44#define STATE2_NONE                0
45#define STATE2_DESIGNATED_KSC5601  1
46
47#define SPLIT_STATE \
48  unsigned int state1 = state & 0xff, state2 = state >> 8
49#define COMBINE_STATE \
50  state = (state2 << 8) | state1
51
52static int
53iso2022_kr_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
54{
55  state_t state = conv->istate;
56  SPLIT_STATE;
57  int count = 0;
58  unsigned char c;
59  for (;;) {
60    c = *s;
61    if (c == ESC) {
62      if (n < count+4)
63        goto none;
64      if (s[1] == '$') {
65        if (s[2] == ')') {
66          if (s[3] == 'C') {
67            state2 = STATE2_DESIGNATED_KSC5601;
68            s += 4; count += 4;
69            if (n < count+1)
70              goto none;
71            continue;
72          }
73        }
74      }
75      goto ilseq;
76    }
77    if (c == SO) {
78      if (state2 != STATE2_DESIGNATED_KSC5601)
79        goto ilseq;
80      state1 = STATE_TWOBYTE;
81      s++; count++;
82      if (n < count+1)
83        goto none;
84      continue;
85    }
86    if (c == SI) {
87      state1 = STATE_ASCII;
88      s++; count++;
89      if (n < count+1)
90        goto none;
91      continue;
92    }
93    break;
94  }
95  switch (state1) {
96    case STATE_ASCII:
97      if (c < 0x80) {
98        int ret = ascii_mbtowc(conv,pwc,s,1);
99        if (ret == RET_ILSEQ)
100          goto ilseq;
101        if (ret != 1) abort();
102#if 0 /* Accept ISO-2022-KR according to CJK.INF. */
103        if (*pwc == 0x000a || *pwc == 0x000d)
104          state2 = STATE2_NONE;
105#endif
106        COMBINE_STATE;
107        conv->istate = state;
108        return count+1;
109      } else
110        goto ilseq;
111    case STATE_TWOBYTE:
112      if (n < count+2)
113        goto none;
114      if (state2 != STATE2_DESIGNATED_KSC5601) abort();
115      if (s[0] < 0x80 && s[1] < 0x80) {
116        int ret = ksc5601_mbtowc(conv,pwc,s,2);
117        if (ret == RET_ILSEQ)
118          goto ilseq;
119        if (ret != 2) abort();
120        COMBINE_STATE;
121        conv->istate = state;
122        return count+2;
123      } else
124        goto ilseq;
125    default: abort();
126  }
127
128none:
129  COMBINE_STATE;
130  conv->istate = state;
131  return RET_TOOFEW(count);
132
133ilseq:
134  COMBINE_STATE;
135  conv->istate = state;
136  return RET_SHIFT_ILSEQ(count);
137}
138
139static int
140iso2022_kr_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
141{
142  state_t state = conv->ostate;
143  SPLIT_STATE;
144  unsigned char buf[2];
145  int ret;
146
147  /* Try ASCII. */
148  ret = ascii_wctomb(conv,buf,wc,1);
149  if (ret != RET_ILUNI) {
150    if (ret != 1) abort();
151    if (buf[0] < 0x80) {
152      int count = (state1 == STATE_ASCII ? 1 : 2);
153      if (n < count)
154        return RET_TOOSMALL;
155      if (state1 != STATE_ASCII) {
156        r[0] = SI;
157        r += 1;
158        state1 = STATE_ASCII;
159      }
160      r[0] = buf[0];
161      if (wc == 0x000a || wc == 0x000d)
162        state2 = STATE2_NONE;
163      COMBINE_STATE;
164      conv->ostate = state;
165      return count;
166    }
167  }
168
169  /* Try KS C 5601-1992. */
170  ret = ksc5601_wctomb(conv,buf,wc,2);
171  if (ret != RET_ILUNI) {
172    if (ret != 2) abort();
173    if (buf[0] < 0x80 && buf[1] < 0x80) {
174      int count = (state2 == STATE2_DESIGNATED_KSC5601 ? 0 : 4) + (state1 == STATE_TWOBYTE ? 0 : 1) + 2;
175      if (n < count)
176        return RET_TOOSMALL;
177      if (state2 != STATE2_DESIGNATED_KSC5601) {
178        r[0] = ESC;
179        r[1] = '$';
180        r[2] = ')';
181        r[3] = 'C';
182        r += 4;
183        state2 = STATE2_DESIGNATED_KSC5601;
184      }
185      if (state1 != STATE_TWOBYTE) {
186        r[0] = SO;
187        r += 1;
188        state1 = STATE_TWOBYTE;
189      }
190      r[0] = buf[0];
191      r[1] = buf[1];
192      COMBINE_STATE;
193      conv->ostate = state;
194      return count;
195    }
196  }
197
198  return RET_ILUNI;
199}
200
201static int
202iso2022_kr_reset (conv_t conv, unsigned char *r, int n)
203{
204  state_t state = conv->ostate;
205  SPLIT_STATE;
206  (void)state2;
207  if (state1 != STATE_ASCII) {
208    if (n < 1)
209      return RET_TOOSMALL;
210    r[0] = SI;
211    /* conv->ostate = 0; will be done by the caller */
212    return 1;
213  } else
214    return 0;
215}
216
217#undef COMBINE_STATE
218#undef SPLIT_STATE
219#undef STATE2_DESIGNATED_KSC5601
220#undef STATE2_NONE
221#undef STATE_TWOBYTE
222#undef STATE_ASCII
223