iso2022_jp3.h

libiconv是一个很不错的字符集转换库。程序接口也很简单

  if (lasttwo) {
    /* Attempt to combine the last character with this one. */
    unsigned int idx;
    unsigned int len;

    if (wc == 0x02e5)
      idx = iso2022_jp3_comp_table02e5_idx,
      len = iso2022_jp3_comp_table02e5_len;
    else if (wc == 0x02e9)
      idx = iso2022_jp3_comp_table02e9_idx,
      len = iso2022_jp3_comp_table02e9_len;
    else if (wc == 0x0300)
      idx = iso2022_jp3_comp_table0300_idx,
      len = iso2022_jp3_comp_table0300_len;
    else if (wc == 0x0301)
      idx = iso2022_jp3_comp_table0301_idx,
      len = iso2022_jp3_comp_table0301_len;
    else if (wc == 0x309a)
      idx = iso2022_jp3_comp_table309a_idx,
      len = iso2022_jp3_comp_table309a_len;
    else
      goto not_combining;

    do
      if (iso2022_jp3_comp_table_data[idx].base == lasttwo)
        break;
    while (++idx, --len > 0);

    if (len > 0) {
      /* Output the combined character. */
      /* We know the combined character is in JISX0213 plane 1, but
         the buffered character may have been in JISX0208 or in
         JISX0213 plane 1. */
      count = (state != STATE_JISX02131 ? 4 : 0) + 2;
      if (n < count)
        return RET_TOOSMALL;
      if (state != STATE_JISX02131) {
        r[0] = ESC;
        r[1] = '$';
        r[2] = '(';
        r[3] = 'O';
        r += 4;
        state = STATE_JISX02131;
      }
      lasttwo = iso2022_jp3_comp_table_data[idx].composed;
      r[0] = (lasttwo >> 8) & 0xff;
      r[1] = lasttwo & 0xff;
      COMBINE_STATE_NO_LASTTWO;
      conv->ostate = state;
      return count;
    }

  not_combining:
    /* Output the buffered character. */
    /* We know it is in JISX0208 or in JISX0213 plane 1. */
    count = (prevstate != state ? 3 : 0) + 2;
    if (n < count)
      return RET_TOOSMALL;
    if (prevstate != state) {
      if (state != STATE_JISX0208) abort();
      r[0] = ESC;
      r[1] = '$';
      r[2] = 'B';
      r += 3;
    }
    r[0] = (lasttwo >> 8) & 0xff;
    r[1] = lasttwo & 0xff;
    r += 2;
  }

  /* Try ASCII. */
  ret = ascii_wctomb(conv,buf,wc,1);
  if (ret != RET_ILUNI) {
    if (ret != 1) abort();
    if (buf[0] < 0x80) {
      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];
      COMBINE_STATE_NO_LASTTWO;
      conv->ostate = state;
      return count;
    }
  }

  /* Try JIS X 0201-1976 Roman. */
  ret = jisx0201_wctomb(conv,buf,wc,1);
  if (ret != RET_ILUNI) {
    if (ret != 1) abort();
    if (buf[0] < 0x80) {
      count += (state == STATE_JISX0201ROMAN ? 1 : 4);
      if (n < count)
        return RET_TOOSMALL;
      if (state != STATE_JISX0201ROMAN) {
        r[0] = ESC;
        r[1] = '(';
        r[2] = 'J';
        r += 3;
        state = STATE_JISX0201ROMAN;
      }
      r[0] = buf[0];
      COMBINE_STATE_NO_LASTTWO;
      conv->ostate = state;
      return count;
    }
  }

  jch = ucs4_to_jisx0213(wc);

  /* 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) {
      if (jch & 0x0080) {
        /* A possible match in comp_table_data. Buffer it. */
        prevstate = state;
        lasttwo = jch & 0x7f7f;
        state = STATE_JISX0208;
        COMBINE_STATE;
        conv->ostate = state;
        return count;
      } else {
        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];
        COMBINE_STATE_NO_LASTTWO;
        conv->ostate = state;
        return count;
      }
    }
  }

  /* Try JISX 0213 plane 1 and JISX 0213 plane 2. */
  if (jch != 0) {
    if (jch & 0x8000) {
      /* JISX 0213 plane 2. */
      if (state != STATE_JISX02132) {
        count += 4;
        if (n < count)
          return RET_TOOSMALL;
        r[0] = ESC;
        r[1] = '$';
        r[2] = '(';
        r[3] = 'P';
        r += 4;
        state = STATE_JISX02132;
      }
    } else {
      /* JISX 0213 plane 1. */
      if (state != STATE_JISX02131) {
        count += 4;
        if (n < count)
          return RET_TOOSMALL;
        r[0] = ESC;
        r[1] = '$';
        r[2] = '(';
        r[3] = 'O';
        r += 4;
        state = STATE_JISX02131;
      }
    }
    if (jch & 0x0080) {
      /* A possible match in comp_table_data. We have to buffer it. */
      /* We know it's a JISX 0213 plane 1 character. */
      if (jch & 0x8000) abort();
      prevstate = state;
      lasttwo = jch & 0x7f7f;
      COMBINE_STATE;
      conv->ostate = state;
      return count;
    }
    count += 2;
    if (n < count)
      return RET_TOOSMALL;
    r[0] = (jch >> 8) & 0x7f;
    r[1] = jch & 0x7f;
    COMBINE_STATE_NO_LASTTWO;
    conv->ostate = state;
    return count;
  }

  /* Try JIS X 0201-1976 Katakana. This is not officially part of
     ISO-2022-JP-3. Therefore we try it after all other attempts. */
  ret = jisx0201_wctomb(conv,buf,wc,1);
  if (ret != RET_ILUNI) {
    if (ret != 1) abort();
    if (buf[0] >= 0x80) {
      count += (state == STATE_JISX0201KATAKANA ? 1 : 4);
      if (n < count)
        return RET_TOOSMALL;
      if (state != STATE_JISX0201KATAKANA) {
        r[0] = ESC;
        r[1] = '(';
        r[2] = 'I';
        r += 3;
        state = STATE_JISX0201KATAKANA;
      }
      r[0] = buf[0]-0x80;
      COMBINE_STATE_NO_LASTTWO;
      conv->ostate = state;
      return count;
    }
  }

  return RET_ILUNI;
}

static int
iso2022_jp3_reset (conv_t conv, unsigned char *r, int n)
{
  state_t state = conv->ostate;
  SPLIT_STATE;
  {
    int count =
      (lasttwo ? (prevstate != state ? 3 : 0) + 2 : 0)
      + (state != STATE_ASCII ? 3 : 0);
    if (n < count)
      return RET_TOOSMALL;
    if (lasttwo) {
      if (prevstate != state) {
        if (state != STATE_JISX0208) abort();
        r[0] = ESC;
        r[1] = '$';
        r[2] = 'B';
        r += 3;
      }
      r[0] = (lasttwo >> 8) & 0xff;
      r[1] = lasttwo & 0xff;
      r += 2;
    }
    if (state != STATE_ASCII) {
      r[0] = ESC;
      r[1] = '(';
      r[2] = 'B';
    }
    /* conv->ostate = 0; will be done by the caller */
    return count;
  }
}

#undef COMBINE_STATE_NO_LASTTWO
#undef COMBINE_STATE
#undef SPLIT_STATE
#undef STATE_JISX02132
#undef STATE_JISX02131
#undef STATE_JISX0208
#undef STATE_JISX0201KATAKANA
#undef STATE_JISX0201ROMAN
#undef STATE_ASCII