iso2022_cnext.h

libiconv是一个很不错的字符集转换库。程序接口也很简单

/*
 * 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.
 */

/*
 * ISO-2022-CN-EXT
 */

/* Specification: RFC 1922 */

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

/*
 * The state is composed of one of the following values
 */
#define STATE_ASCII          0
#define STATE_TWOBYTE        1
/*
 * and one of the following values, << 8
 */
#define STATE2_NONE                   0
#define STATE2_DESIGNATED_GB2312      1
#define STATE2_DESIGNATED_CNS11643_1  2
#define STATE2_DESIGNATED_ISO_IR_165  3
/*
 * and one of the following values, << 16
 */
#define STATE3_NONE                   0
#define STATE3_DESIGNATED_CNS11643_2  1
/*
 * and one of the following values, << 24
 */
#define STATE4_NONE                   0
#define STATE4_DESIGNATED_CNS11643_3  1
#define STATE4_DESIGNATED_CNS11643_4  2
#define STATE4_DESIGNATED_CNS11643_5  3
#define STATE4_DESIGNATED_CNS11643_6  4
#define STATE4_DESIGNATED_CNS11643_7  5

#define SPLIT_STATE \
  unsigned int state1 = state & 0xff, state2 = (state >> 8) & 0xff, state3 = (state >> 16) & 0xff, state4 = state >> 24
#define COMBINE_STATE \
  state = (state4 << 24) | (state3 << 16) | (state2 << 8) | state1

static int
iso2022_cn_ext_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
{
  state_t state = conv->istate;
  SPLIT_STATE;
  int count = 0;
  unsigned char c;
  for (;;) {
    c = *s;
    if (c == ESC) {
      if (n < count+4)
        goto none;
      if (s[1] == '$') {
        if (s[2] == ')') {
          if (s[3] == 'A') {
            state2 = STATE2_DESIGNATED_GB2312;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'G') {
            state2 = STATE2_DESIGNATED_CNS11643_1;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'E') {
            state2 = STATE2_DESIGNATED_ISO_IR_165;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
        }
        if (s[2] == '*') {
          if (s[3] == 'H') {
            state3 = STATE3_DESIGNATED_CNS11643_2;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
        }
        if (s[2] == '+') {
          if (s[3] == 'I') {
            state4 = STATE4_DESIGNATED_CNS11643_3;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'J') {
            state4 = STATE4_DESIGNATED_CNS11643_4;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'K') {
            state4 = STATE4_DESIGNATED_CNS11643_5;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'L') {
            state4 = STATE4_DESIGNATED_CNS11643_6;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
          if (s[3] == 'M') {
            state4 = STATE4_DESIGNATED_CNS11643_7;
            s += 4; count += 4;
            if (n < count+1)
              goto none;
            continue;
          }
        }
      }
      if (s[1] == 'N') {
        switch (state3) {
          case STATE3_NONE:
            return RET_ILSEQ;
          case STATE3_DESIGNATED_CNS11643_2:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_2_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          default: abort();
        }
      }
      if (s[1] == 'O') {
        switch (state4) {
          case STATE4_NONE:
            return RET_ILSEQ;
          case STATE4_DESIGNATED_CNS11643_3:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_3_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          case STATE4_DESIGNATED_CNS11643_4:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_4_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          case STATE4_DESIGNATED_CNS11643_5:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_5_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          case STATE4_DESIGNATED_CNS11643_6:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_6_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          case STATE4_DESIGNATED_CNS11643_7:
            if (s[2] < 0x80 && s[3] < 0x80) {
              int ret = cns11643_7_mbtowc(conv,pwc,s+2,2);
              if (ret == RET_ILSEQ)
                return RET_ILSEQ;
              if (ret != 2) abort();
              COMBINE_STATE;
              conv->istate = state;
              return count+4;
            } else
              return RET_ILSEQ;
          default: abort();
        }
      }
      return RET_ILSEQ;
    }
    if (c == SO) {
      if (state2 != STATE2_DESIGNATED_GB2312 && state2 != STATE2_DESIGNATED_CNS11643_1 && state2 != STATE2_DESIGNATED_ISO_IR_165)
        return RET_ILSEQ;
      state1 = STATE_TWOBYTE;
      s++; count++;
      if (n < count+1)
        goto none;
      continue;
    }
    if (c == SI) {
      state1 = STATE_ASCII;
      s++; count++;
      if (n < count+1)
        goto none;
      continue;
    }
    break;
  }
  switch (state1) {
    case STATE_ASCII:
      if (c < 0x80) {
        int ret = ascii_mbtowc(conv,pwc,s,1);
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 1) abort();
        if (*pwc == 0x000a || *pwc == 0x000d) {
          state2 = STATE2_NONE; state3 = STATE3_NONE; state4 = STATE3_NONE;
        }
        COMBINE_STATE;
        conv->istate = state;
        return count+1;
      } else
        return RET_ILSEQ;
    case STATE_TWOBYTE:
      if (n < count+2)
        goto none;
      if (s[0] < 0x80 && s[1] < 0x80) {
        int ret;
        switch (state2) {
          case STATE2_NONE:
            return RET_ILSEQ;
          case STATE2_DESIGNATED_GB2312:
            ret = gb2312_mbtowc(conv,pwc,s,2); break;
          case STATE2_DESIGNATED_CNS11643_1:
            ret = cns11643_1_mbtowc(conv,pwc,s,2); break;
          case STATE2_DESIGNATED_ISO_IR_165:
            ret = isoir165_mbtowc(conv,pwc,s,2); break;
          default: abort();
        }
        if (ret == RET_ILSEQ)
          return RET_ILSEQ;
        if (ret != 2) abort();
        COMBINE_STATE;
        conv->istate = state;
        return count+2;
      } else
        return RET_ILSEQ;
    default: abort();
  }

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