ces_gbk.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.
 */

/*
 * GBK, CP936
 */

static int
ces_gbk_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
{
  unsigned char c = *s;

  /* Code set 0 (ASCII or GB 1988-89) */
  if (c < 0x80)
    return ascii_mbtowc(conv,pwc,s,n);
  /* Code set 1 (GBK) */
  if (c >= 0x81 && c < 0xff) {
    if (n < 2)
      return RET_TOOFEW(0);
    return gbk_mbtowc(conv,pwc,s,2);
  }
  return RET_ILSEQ;
}

static int
ces_gbk_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
{
  unsigned char buf[2];
  int ret;

  /* Code set 0 (ASCII or GB 1988-89) */
  ret = ascii_wctomb(conv,r,wc,n);
  if (ret != RET_ILUNI)
    return ret;

  /* Code set 1 (GBK) */
  ret = gbk_wctomb(conv,buf,wc,2);
  if (ret != RET_ILUNI) {
    if (ret != 2) abort();
    if (n < 2)
      return RET_TOOSMALL;
    r[0] = buf[0];
    r[1] = buf[1];
    return 2;
  }

  return RET_ILUNI;
}