/*
 * "streamable kanji code filter and converter"
 * Copyright (c) 1998-2002 HappySize, Inc. All rights reserved.
 *
 * LICENSE NOTICES
 *
 * This file is part of "streamable kanji code filter and converter",
 * which is distributed under the terms of GNU Lesser General Public 
 * License (version 2) as published by the Free Software Foundation.
 *
 * This software 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with "streamable kanji code filter and converter";
 * if not, write to the Free Software Foundation, Inc., 59 Temple Place,
 * Suite 330, Boston, MA  02111-1307  USA
 *
 * The author of this file:
 *
 */
/*
 * the source code included in this files was separated from mbfilter_cn.c
 * by moriyoshi koizumi <moriyoshi@php.net> on 4 dec 2002.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "mbfilter.h"
#include "mbfilter_cp936.h"

#include "unicode_table_cp936.h"

static int mbfl_filt_ident_cp936(int c, mbfl_identify_filter *filter);

static const unsigned char mblen_table_cp936[] = { /* 0x81-0xFE */
  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 *mbfl_encoding_cp936_aliases[] = {"CP-936", "GBK", NULL};

const mbfl_encoding mbfl_encoding_cp936 = {
	mbfl_no_encoding_cp936,
	"CP936",
	"CP936",
	(const char *(*)[])&mbfl_encoding_cp936_aliases,
	mblen_table_cp936,
	MBFL_ENCTYPE_MBCS
};

const struct mbfl_identify_vtbl vtbl_identify_cp936 = {
	mbfl_no_encoding_cp936,
	mbfl_filt_ident_common_ctor,
	mbfl_filt_ident_common_dtor,
	mbfl_filt_ident_cp936
};

const struct mbfl_convert_vtbl vtbl_cp936_wchar = {
	mbfl_no_encoding_cp936,
	mbfl_no_encoding_wchar,
	mbfl_filt_conv_common_ctor,
	mbfl_filt_conv_common_dtor,
	mbfl_filt_conv_cp936_wchar,
	mbfl_filt_conv_common_flush
};

const struct mbfl_convert_vtbl vtbl_wchar_cp936 = {
	mbfl_no_encoding_wchar,
	mbfl_no_encoding_cp936,
	mbfl_filt_conv_common_ctor,
	mbfl_filt_conv_common_dtor,
	mbfl_filt_conv_wchar_cp936,
	mbfl_filt_conv_common_flush
};


#define CK(statement)	do { if ((statement) < 0) return (-1); } while (0)

/*
 * CP936 => wchar
 */
int
mbfl_filt_conv_cp936_wchar(int c, mbfl_convert_filter *filter)
{
	int c1, w;

	switch (filter->status) {
	case 0:
		if (c >= 0 && c < 0x80) {	/* latin */
			CK((*filter->output_function)(c, filter->data));
		} else if (c == 0x80) {	/* euro sign */
			CK((*filter->output_function)(0x20ac, filter->data));
		} else if (c > 0x80 && c < 0xff) {	/* dbcs lead byte */
			filter->status = 1;
			filter->cache = c;
		} else {
			w = c & MBFL_WCSGROUP_MASK;
			w |= MBFL_WCSGROUP_THROUGH;
			CK((*filter->output_function)(w, filter->data));
		}
		break;

	case 1:		/* dbcs second byte */
		filter->status = 0;
		c1 = filter->cache;
		if ( c1 < 0xff && c1 > 0x80 && c > 0x39 && c < 0xff && c != 0x7f) {
			w = (c1 - 0x81)*192 + (c - 0x40);
			if (w >= 0 && w < cp936_ucs_table_size) {
				w = cp936_ucs_table[w];
			} else {
				w = 0;
			}
			if (w <= 0) {
				w = (c1 << 8) | c;
				w &= MBFL_WCSPLANE_MASK;
				w |= MBFL_WCSPLANE_WINCP936;
			}
			CK((*filter->output_function)(w, filter->data));
		} else if ((c >= 0 && c < 0x21) || c == 0x7f) {		/* CTLs */
			CK((*filter->output_function)(c, filter->data));
		} else {
			w = (c1 << 8) | c;
			w &= MBFL_WCSGROUP_MASK;
			w |= MBFL_WCSGROUP_THROUGH;
			CK((*filter->output_function)(w, filter->data));
		}
		break;

	default:
		filter->status = 0;
		break;
	}

	return c;
}

/*
 * wchar => CP936
 */
int
mbfl_filt_conv_wchar_cp936(int c, mbfl_convert_filter *filter)
{
	int c1, s;

	s = 0;
	if (c >= ucs_a1_cp936_table_min && c < ucs_a1_cp936_table_max) {
		s = ucs_a1_cp936_table[c - ucs_a1_cp936_table_min];
	} else if (c >= ucs_a2_cp936_table_min && c < ucs_a2_cp936_table_max) {
		s = ucs_a2_cp936_table[c - ucs_a2_cp936_table_min];
	} else if (c >= ucs_a3_cp936_table_min && c < ucs_a3_cp936_table_max) {
		s = ucs_a3_cp936_table[c - ucs_a3_cp936_table_min];
	} else if (c >= ucs_i_cp936_table_min && c < ucs_i_cp936_table_max) {
		s = ucs_i_cp936_table[c - ucs_i_cp936_table_min];
	} else if (c >= ucs_ci_cp936_table_min && c < ucs_ci_cp936_table_max) {
		s = ucs_ci_cp936_table[c - ucs_ci_cp936_table_min];
	} else if (c >= ucs_cf_cp936_table_min && c < ucs_cf_cp936_table_max) {
		s = ucs_cf_cp936_table[c - ucs_cf_cp936_table_min];
	} else if (c >= ucs_sfv_cp936_table_min && c < ucs_sfv_cp936_table_max) {
		s = ucs_sfv_cp936_table[c - ucs_sfv_cp936_table_min];
	} else if (c >= ucs_hff_cp936_table_min && c < ucs_hff_cp936_table_max) {
		s = ucs_hff_cp936_table[c - ucs_hff_cp936_table_min];
	}
	if (s <= 0) {
		c1 = c & ~MBFL_WCSPLANE_MASK;
		if (c1 == MBFL_WCSPLANE_WINCP936) {
			s = c & MBFL_WCSPLANE_MASK;
		}
		if (c == 0) {
			s = 0;
		} else if (s <= 0) {
			s = -1;
		}
	}
	if (s >= 0) {
		if (s < 0x80) {	/* latin */
			CK((*filter->output_function)(s, filter->data));
		} else {
			CK((*filter->output_function)((s >> 8) & 0xff, filter->data));
			CK((*filter->output_function)(s & 0xff, filter->data));
		}
	} else {
		if (filter->illegal_mode != MBFL_OUTPUTFILTER_ILLEGAL_MODE_NONE) {
			CK(mbfl_filt_conv_illegal_output(c, filter));
		}
	}

	return c;
}

static int mbfl_filt_ident_cp936(int c, mbfl_identify_filter *filter)
{
	if (filter->status) {		/* kanji second char */
		if (c < 0x40 || c > 0xfe || c == 0x7f) {	/* bad */
		    filter->flag = 1;
		}
		filter->status = 0;
	} else if (c >= 0 && c < 0x80) {	/* latin  ok */
		;
	} else if (c > 0x80 && c < 0xff) {	/* DBCS lead byte */
		filter->status = 1;
	} else {							/* bad */
		filter->flag = 1;
	}

	return c;
}