/**********************************************************************
  gbk.c -  Oniguruma (regular expression library)
**********************************************************************/
/*-
 * Copyright (c) 2002-2007  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "regenc.h"

static const int EncLen_GBK[] = {
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1
};

static const char GBK_CAN_BE_TRAIL_TABLE[256] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0
};

#define GBK_ISMB_FIRST(byte)  (EncLen_GBK[byte] > 1)
#define GBK_ISMB_TRAIL(byte)  GBK_CAN_BE_TRAIL_TABLE[(byte)]

typedef enum { FAILURE = -2, ACCEPT = -1, S0 = 0, S1 } state_t;
#define A ACCEPT
#define F FAILURE
static const signed char trans[][0x100] = {
  { /* S0   0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f */
    /* 0 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 1 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 2 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 3 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 4 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 5 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 6 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 7 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 8 */ A, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* 9 */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* a */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* b */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* c */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* d */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* e */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    /* f */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, F
  },
  { /* S1   0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f */
    /* 0 */ F, F, F, F, F, F, F, F, F, F, F, F, F, F, F, F,
    /* 1 */ F, F, F, F, F, F, F, F, F, F, F, F, F, F, F, F,
    /* 2 */ F, F, F, F, F, F, F, F, F, F, F, F, F, F, F, F,
    /* 3 */ F, F, F, F, F, F, F, F, F, F, F, F, F, F, F, F,
    /* 4 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 5 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 6 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 7 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, F,
    /* 8 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* 9 */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* a */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* b */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* c */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* d */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* e */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A,
    /* f */ A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, F
  }
};
#undef A
#undef F

static int
gbk_mbc_enc_len(const UChar* p, const UChar* e, OnigEncoding enc ARG_UNUSED)
{
  int firstbyte = *p++;
  state_t s = trans[0][firstbyte];
#define RETURN(n) \
    return s == ACCEPT ? ONIGENC_CONSTRUCT_MBCLEN_CHARFOUND(n) : \
                         ONIGENC_CONSTRUCT_MBCLEN_INVALID()
  if (s < 0) RETURN(1);
  if (p == e) return ONIGENC_CONSTRUCT_MBCLEN_NEEDMORE(EncLen_GBK[firstbyte]-1);
  s = trans[s][*p++];
  RETURN(2);
#undef RETURN
}

static OnigCodePoint
gbk_mbc_to_code(const UChar* p, const UChar* end, OnigEncoding enc)
{
  return onigenc_mbn_mbc_to_code(enc, p, end);
}

static int
gbk_code_to_mbc(OnigCodePoint code, UChar *buf, OnigEncoding enc)
{
  return onigenc_mb2_code_to_mbc(enc, code, buf);
}

static int
gbk_mbc_case_fold(OnigCaseFoldType flag, const UChar** pp, const UChar* end,
                    UChar* lower, OnigEncoding enc)
{
  return onigenc_mbn_mbc_case_fold(enc, flag,
                                   pp, end, lower);
}

#if 0
static int
gbk_is_mbc_ambiguous(OnigCaseFoldType flag,
		       const UChar** pp, const UChar* end, OnigEncoding enc)
{
  return onigenc_mbn_is_mbc_ambiguous(enc, flag, pp, end);
}
#endif

static int
gbk_is_code_ctype(OnigCodePoint code, unsigned int ctype, OnigEncoding enc)
{
  return onigenc_mb2_is_code_ctype(enc, code, ctype);
}

static UChar*
gbk_left_adjust_char_head(const UChar* start, const UChar* s, const UChar* end, OnigEncoding enc)
{
  const UChar *p;
  int len;

  if (s <= start) return (UChar* )s;
  p = s;

  if (GBK_ISMB_TRAIL(*p)) {
    while (p > start) {
      if (! GBK_ISMB_FIRST(*--p)) {
	p++;
	break;
      }
    }
  }
  len = enclen(enc, p, end);
  if (p + len > s) return (UChar* )p;
  p += len;
  return (UChar* )(p + ((s - p) & ~1));
}

static int
gbk_is_allowed_reverse_match(const UChar* s, const UChar* end ARG_UNUSED, OnigEncoding enc ARG_UNUSED)
{
  const UChar c = *s;
  return (GBK_ISMB_TRAIL(c) ? FALSE : TRUE);
}

OnigEncodingDefine(gbk, GBK) = {
  gbk_mbc_enc_len,
  "GBK",      /* name */
  2,          /* max enc length */
  1,          /* min enc length */
  onigenc_is_mbc_newline_0x0a,
  gbk_mbc_to_code,
  onigenc_mb2_code_to_mbclen,
  gbk_code_to_mbc,
  gbk_mbc_case_fold,
  onigenc_ascii_apply_all_case_fold,
  onigenc_ascii_get_case_fold_codes_by_str,
  onigenc_minimum_property_name_to_ctype,
  gbk_is_code_ctype,
  onigenc_not_support_get_ctype_code_range,
  gbk_left_adjust_char_head,
  gbk_is_allowed_reverse_match,
  0,
  ONIGENC_FLAG_NONE,
};
/*
 * Name: GBK
 * MIBenum: 113
 * Link: http://www.iana.org/assignments/character-sets
 * Link: http://www.iana.org/assignments/charset-reg/GBK
 * Link: http://www.microsoft.com/globaldev/reference/dbcs/936.mspx
 */
ENC_ALIAS("CP936", "GBK")
