lib/iso2022_kr.h

   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  * 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
  52 static int
  53 iso2022_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       return RET_ILSEQ;
  76     }
  77     if (c == SO) {
  78       if (state2 != STATE2_DESIGNATED_KSC5601)
  79         return RET_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           return RET_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         return RET_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           return RET_ILSEQ;
 119         if (ret != 2) abort();
 120         COMBINE_STATE;
 121         conv->istate = state;
 122         return count+2;
 123       } else
 124         return RET_ILSEQ;
 125     default: abort();
 126   }
 127
 128 none:
 129   COMBINE_STATE;
 130   conv->istate = state;
 131   return RET_TOOFEW(count);
 132 }
 133
 134 static int
 135 iso2022_kr_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
 136 {
 137   state_t state = conv->ostate;
 138   SPLIT_STATE;
 139   unsigned char buf[2];
 140   int ret;
 141
 142   /* Try ASCII. */
 143   ret = ascii_wctomb(conv,buf,wc,1);
 144   if (ret != RET_ILUNI) {
 145     if (ret != 1) abort();
 146     if (buf[0] < 0x80) {
 147       int count = (state1 == STATE_ASCII ? 1 : 2);
 148       if (n < count)
 149         return RET_TOOSMALL;
 150       if (state1 != STATE_ASCII) {
 151         r[0] = SI;
 152         r += 1;
 153         state1 = STATE_ASCII;
 154       }
 155       r[0] = buf[0];
 156       if (wc == 0x000a || wc == 0x000d)
 157         state2 = STATE2_NONE;
 158       COMBINE_STATE;
 159       conv->ostate = state;
 160       return count;
 161     }
 162   }
 163
 164   /* Try KS C 5601-1992. */
 165   ret = ksc5601_wctomb(conv,buf,wc,2);
 166   if (ret != RET_ILUNI) {
 167     if (ret != 2) abort();
 168     if (buf[0] < 0x80 && buf[1] < 0x80) {
 169       int count = (state2 == STATE2_DESIGNATED_KSC5601 ? 0 : 4) + (state1 == STATE_TWOBYTE ? 0 : 1) + 2;
 170       if (n < count)
 171         return RET_TOOSMALL;
 172       if (state2 != STATE2_DESIGNATED_KSC5601) {
 173         r[0] = ESC;
 174         r[1] = '$';
 175         r[2] = ')';
 176         r[3] = 'C';
 177         r += 4;
 178         state2 = STATE2_DESIGNATED_KSC5601;
 179       }
 180       if (state1 != STATE_TWOBYTE) {
 181         r[0] = SO;
 182         r += 1;
 183         state1 = STATE_TWOBYTE;
 184       }
 185       r[0] = buf[0];
 186       r[1] = buf[1];
 187       COMBINE_STATE;
 188       conv->ostate = state;
 189       return count;
 190     }
 191   }
 192
 193   return RET_ILUNI;
 194 }
 195
 196 static int
 197 iso2022_kr_reset (conv_t conv, unsigned char *r, int n)
 198 {
 199   state_t state = conv->ostate;
 200   SPLIT_STATE;
 201   (void)state2;
 202   if (state1 != STATE_ASCII) {
 203     if (n < 1)
 204       return RET_TOOSMALL;
 205     r[0] = SI;
 206     /* conv->ostate = 0; will be done by the caller */
 207     return 1;
 208   } else
 209     return 0;
 210 }
 211
 212 #undef COMBINE_STATE
 213 #undef SPLIT_STATE
 214 #undef STATE2_DESIGNATED_KSC5601
 215 #undef STATE2_NONE
 216 #undef STATE_TWOBYTE
 217 #undef STATE_ASCII