/*
 * Copyright (C) 1999-2001 Free Software Foundation, Inc.
 * This file is part of the GNU LIBICONV Library.
 *
 * The GNU LIBICONV Library is free software; you can redistribute it
 * and/or modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * The GNU LIBICONV Library is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
 * If not, write to the Free Software Foundation, Inc., 59 Temple Place -
 * Suite 330, Boston, MA 02111-1307, USA.
 */

/*
 * cp50220
 */

#define ESC 0x1b
#define SO  0x0e
#define SI  0x0f

/*
 * The state can be one of the following values.
 */
#define STATE_ASCII             0
#define STATE_JISX0201KATAKANA  1
#define STATE_JISX0208          2
#define STATE_SHIFTIN           3

static int
cp50220_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
{
  state_t state = conv->istate;
  int count = 0;
  unsigned char c;
  for (;;) {
    c = *s;
    if (c == ESC) {
      if (n < count+3)
        goto none;
      if (s[1] == '(') {
        if (s[2] == 'B' || s[2] == 'J') {
          state = STATE_ASCII;
          s += 3; count += 3;
          if (n < count+1)
            goto none;
          continue;
        }
        if (s[2] == 'I') {
          state = STATE_JISX0201KATAKANA;
          s += 3; count += 3;
          if (n < count+1)
            goto none;
          continue;
        }
        return RET_ILSEQ;
      }
      if (s[1] == '$') {
        if (s[2] == '@' || s[2] == 'B') {
          /* We don't distinguish JIS X 0208-1978 and JIS X 0208-1983. */
          state = STATE_JISX0208;
          s += 3; count += 3;
          if (n < count+1)
            goto none;
          continue;
        }
        return RET_ILSEQ;
      }
      return RET_ILSEQ;
    }
    else if (c == SO) {
      state = STATE_SHIFTIN;
      s += 1; count += 1;
      if (n < count+1)
        goto none;
      continue;
    }
    else if (c == SI) {
      state = STATE_ASCII;
      s += 1; count += 1;
      if (n < count+1)
        goto none;
      continue;
    }
    else if (0x80 <= c && state == STATE_ASCII) {
      state = STATE_SHIFTIN;
    }
    break;
  }

  switch (state) {
    int ret;
    unsigned char c1, c2;
    case STATE_ASCII:
      if (c < 0x80) {
        ret = ascii_mbtowc(conv,pwc,s,1);
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 1) abort();
        conv->istate = state;
        return count+1;
      } else
        return RET_ILSEQ;
    case STATE_JISX0201KATAKANA:
      if (c < 0x80) {
        unsigned char buf = c+0x80;
        ret = jisx0201_mbtowc(conv,pwc,&buf,1);
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 1) abort();
        conv->istate = state;
        return count+1;
      } else
        return RET_ILSEQ;
    case STATE_JISX0208:
      if (n < count+2)
        goto none;
      if (s[0] == 0x21 || s[0] == 0x22 || s[0] == 0x2d
               || (0x79 <= s[0] && s[0] <= 0x7c))
      {
        /* cp50220 Rows 1,2,13,89-92 */
        unsigned char c1 = s[0];
        unsigned char c2 = s[1];
        if (0x21 <= c2 && c2 <= 0x7e) {
          unsigned char t1 = (c1 - 0x21) >> 1;
          unsigned char t2 = (((c1 - 0x21) & 1) ? 0x5e : 0) + (c2 - 0x21);
          unsigned char buf[2];
          buf[0] = (t1 < 0x1f ? t1+0x81 : t1+0xc1);
          buf[1] = (t2 < 0x3f ? t2+0x40 : t2+0x41);
          ret = cp932ext_mbtowc(conv,pwc,buf,2);
          if (ret == RET_ILSEQ)
            return RET_ILSEQ;
          if (ret != 2) abort();
          conv->istate = state;
          return count+2;
        } else
          return RET_ILSEQ;
      }
      else if (0x21 <= s[0] && s[0] <= 0x7E) {
        /* JIS X 0208 Rows 3-12,14-94 */
        if (0x21 <= s[1] && s[1] <= 0x7e) {
          ret = jisx0208_mbtowc(conv,pwc,s,2);
          if (ret == RET_ILSEQ)
            return RET_ILSEQ;
          if (ret != 2) abort();
          conv->istate = state;
          return count+2;
        } else
          return RET_ILSEQ;
      }
      else if (s[0] <= 0x20 || s[0] == 0x7f) { /* C0,SP,DEL */
        ret = ascii_mbtowc(conv,pwc,s,1);
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 1) abort();
        conv->istate = state;
        return count+1;
      } else
        return RET_ILSEQ;
    case STATE_SHIFTIN:
      c1 = s[0] | 0x80;
      if (0xa1 <= c1 && c1 <= 0xdf) {
        /* JIS X 0201 Katakana */
        ret = jisx0201_mbtowc(conv,pwc,&c1,1);
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 1) abort();
        conv->istate = state;
        return count+1;
      }
      return RET_ILSEQ;
    default: abort();
  }

none:
  conv->istate = state;
  return RET_TOOFEW(count);
}

static unsigned short kana_h2z[] = {
          0x2123, 0x2156, 0x2157, 0x2122, 0x2126, 0x2572, 0x2521,
  0x2523, 0x2525, 0x2527, 0x2529, 0x2563, 0x2565, 0x2567, 0x2543,
  0x213c, 0x2522, 0x2524, 0x2526, 0x2528, 0x252a, 0x252b, 0x252d,
  0x252f, 0x2531, 0x2533, 0x2535, 0x2537, 0x2539, 0x253b, 0x253d,
  0x253f, 0x2541, 0x2544, 0x2546, 0x2548, 0x254a, 0x254b, 0x254c,
  0x254d, 0x254e, 0x254f, 0x2552, 0x2555, 0x2558, 0x255b, 0x255e,
  0x255f, 0x2560, 0x2561, 0x2562, 0x2564, 0x2566, 0x2568, 0x2569,
  0x256a, 0x256b, 0x256c, 0x256d, 0x256f, 0x2573, 0x212b, 0x212c
};

static int
cp50220_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
{
  state_t state = conv->ostate;
  unsigned char buf[2];
  int ret;

  switch (wc) {
    /* JIS X 0201 Roman to ASCII */
    case 0x00a5: wc = 0x005c; break;
    case 0x203e: wc = 0x007e; break;
    /* JIS to Microsoft */
    case 0x2014: wc = 0x2015; break;
  }

  /* Try ASCII. */
  ret = ascii_wctomb(conv,buf,wc,1);
  if (ret != RET_ILUNI) {
    if (ret != 1) abort();
    if (buf[0] < 0x80) {
      int count = (state == STATE_ASCII ? 1 : 4);
      if (n < count)
        return RET_TOOSMALL;
      if (state != STATE_ASCII) {
        r[0] = ESC;
        r[1] = '(';
        r[2] = 'B';
        r += 3;
        state = STATE_ASCII;
      }
      r[0] = buf[0];
      conv->ostate = state;
      return count;
    }
  }

  /* Try JIS X 0208-1990 in place of JIS X 0208-1978 and JIS X 0208-1983. */
  ret = jisx0208_wctomb(conv,buf,wc,2);
  if (ret != RET_ILUNI) {
    if (ret != 2) abort();
    if (buf[0] < 0x80 && buf[1] < 0x80) {
      int count = (state == STATE_JISX0208 ? 2 : 5);
      if (n < count)
        return RET_TOOSMALL;
      if (state != STATE_JISX0208) {
        r[0] = ESC;
        r[1] = '$';
        r[2] = 'B';
        r += 3;
        state = STATE_JISX0208;
      }
      r[0] = buf[0];
      r[1] = buf[1];
      conv->ostate = state;
      return count;
    }
  }

  /* Try JIS X 0201-1976 Kana. */
  ret = jisx0201_wctomb(conv,buf,wc,1);
  if (ret != RET_ILUNI) {
    if (ret != 1) abort();
    if (0xa1 <= buf[0] && buf[0] <= 0xdf) {
      int count = 0;
      if (state == STATE_ASCII || state == STATE_JISX0201KATAKANA) {
        r[0] = ESC;
        r[1] = '$';
        r[2] = 'B';
        r += 3;
        count = 3;
        state = STATE_JISX0208;
      }
      if (0xb6<=buf[0] && buf[0]<=0xc4 || 0xca<=buf[0] && buf[0]<=0xce) {
        if (state == STATE_JISX0208) {
          if (n < count)
            return RET_TOOSMALL;
          state = buf[0];
        } else {
          count += 2;
          if (n < count)
            return RET_TOOSMALL;
          r[0] = kana_h2z[state - 0xa1] / 0x100;
          r[1] = kana_h2z[state - 0xa1] % 0x100;
          state = buf[0];
        }
      }
      else if (buf[0] == 0xde) { /* KATAKANA VOICED SOUND MARK */
        if (state == STATE_JISX0208) {
          count += 2;
          if (n < count)
            return RET_TOOSMALL;
          r[0] = kana_h2z[buf[0] - 0xa1] / 0x100;
          r[1] = kana_h2z[buf[0] - 0xa1] % 0x100;
        } else {
          if (0xb6<=state && state<=0xc4 || 0xca<=state && state<=0xce) {
            count += 2;
            if (n < count)
              return RET_TOOSMALL;
            r[0] = kana_h2z[state - 0xa1] / 0x100;
            r[1] = kana_h2z[state - 0xa1] % 0x100 + 1;
          } else {
            count += 4;
            if (n < count)
              return RET_TOOSMALL;
            r[0] = kana_h2z[state - 0xa1] / 0x100;
            r[1] = kana_h2z[state - 0xa1] % 0x100;
            r[2] = kana_h2z[buf[0] - 0xa1] / 0x100;
            r[3] = kana_h2z[buf[0] - 0xa1] % 0x100;
          }
          state = STATE_JISX0208;
        }
      }
      else if (buf[0] == 0xdf) {  /* KATAKANA SEMI-VOICED SOUND MARK */
        if (state == STATE_JISX0208) {
          count += 2;
          if (n < count)
            return RET_TOOSMALL;
          r[0] = kana_h2z[buf[0] - 0xa1] / 0x100;
          r[1] = kana_h2z[buf[0] - 0xa1] % 0x100;
        } else {
          if (0xca<=state && state<=0xce) {
            count += 2;
            if (n < count)
              return RET_TOOSMALL;
            r[0] = kana_h2z[state - 0xa1] / 0x100;
            r[1] = kana_h2z[state - 0xa1] % 0x100 + 2;
          } else {
            count += 4;
            if (n < count)
              return RET_TOOSMALL;
            r[0] = kana_h2z[state - 0xa1] / 0x100;
            r[1] = kana_h2z[state - 0xa1] % 0x100;
            r[2] = kana_h2z[buf[0] - 0xa1] / 0x100;
            r[3] = kana_h2z[buf[0] - 0xa1] % 0x100;
          }
          state = STATE_JISX0208;
        }
      }
      else {
        if (state == STATE_JISX0208) {
          count += 2;
          if (n < count)
            return RET_TOOSMALL;
          r[0] = kana_h2z[buf[0] - 0xa1] / 0x100;
          r[1] = kana_h2z[buf[0] - 0xa1] % 0x100;
        } else {
          count += 4;
          if (n < count)
            return RET_TOOSMALL;
          r[0] = kana_h2z[state - 0xa1] / 0x100;
          r[1] = kana_h2z[state - 0xa1] % 0x100;
          r[2] = kana_h2z[buf[0] - 0xa1] / 0x100;
          r[3] = kana_h2z[buf[0] - 0xa1] % 0x100;
          state = STATE_JISX0208;
        }
      }
      conv->ostate = state;
      return count;
    }
  }

  /* Try cp932ext */
  ret = cp932ext_wctomb(conv,buf,wc,2);
  if (ret != RET_ILUNI) {
    unsigned char s1, s2;
    int count = (state == STATE_JISX0208 ? 2 : 5);
    if (ret != 2) abort();
    if (n < count)
      return RET_TOOSMALL;
    if (state != STATE_JISX0208) {
      r[0] = ESC;
      r[1] = '$';
      r[2] = 'B';
      r += 3;
      state = STATE_JISX0208;
    }
    s1 = buf[0];
    s2 = buf[1];
    if (s1 == 0x81) {
      unsigned char t1 = (s1 < 0xe0 ? s1-0x81 : s1-0xc1);
      unsigned char t2 = (s2 < 0x80 ? s2-0x40 : s2-0x41);
      r[0] = 2*t1 + (t2 < 0x5e ? 0 : 1) + 0x21;
      r[1] = (t2 < 0x5e ? t2 : t2-0x5e) + 0x21;
      conv->ostate = state;
      return count;
    }
    else
      return RET_ILUNI;
  }

  return RET_ILUNI;
}

static int
cp50220_reset (conv_t conv, unsigned char *r, int n)
{
  state_t state = conv->ostate;
  if (0xa1 <= state && state <= 0xdf) {
    if (n < 5)
      return RET_TOOSMALL;
    r[0] = kana_h2z[state - 0xa1] / 0x100;
    r[1] = kana_h2z[state - 0xa1] % 0x100;
    r[2] = ESC;
    r[3] = '(';
    r[4] = 'B';
    /* conv->ostate = 0; will be done by the caller */
   return 5;
  }
  else if (state != STATE_ASCII) {
    if (n < 3)
      return RET_TOOSMALL;
    r[0] = ESC;
    r[1] = '(';
    r[2] = 'B';
    /* conv->ostate = 0; will be done by the caller */
    return 3;
  } else
    return 0;
}

#undef STATE_SHIFTIN
#undef STATE_JISX0208
#undef STATE_JISX0201KATAKANA
#undef STATE_ASCII