/*
 * "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_ja.c
 * by moriyoshi koizumi <moriyoshi@php.net> on 4 dec 2002.
 * 
 */

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

#include "mbfilter.h"
#include "mbfilter_sjis.h"

#include "unicode_table_cp932_ext.h"
#include "unicode_table_jis.h"

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

static const unsigned char mblen_table_sjis[] = { /* 0x80-0x9f,0xE0-0xFF */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 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,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 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
};

static const char *mbfl_encoding_sjis_aliases[] = {"x-sjis", "SHIFT-JIS", NULL};

const mbfl_encoding mbfl_encoding_sjis = {
	mbfl_no_encoding_sjis,
	"SJIS",
	"Shift_JIS",
	(const char *(*)[])&mbfl_encoding_sjis_aliases,
	mblen_table_sjis,
	MBFL_ENCTYPE_MBCS
};

const struct mbfl_identify_vtbl vtbl_identify_sjis = {
	mbfl_no_encoding_sjis,
	mbfl_filt_ident_common_ctor,
	mbfl_filt_ident_common_dtor,
	mbfl_filt_ident_sjis
};

const struct mbfl_convert_vtbl vtbl_sjis_wchar = {
	mbfl_no_encoding_sjis,
	mbfl_no_encoding_wchar,
	mbfl_filt_conv_common_ctor,
	mbfl_filt_conv_common_dtor,
	mbfl_filt_conv_sjis_wchar,
	mbfl_filt_conv_common_flush
};

const struct mbfl_convert_vtbl vtbl_wchar_sjis = {
	mbfl_no_encoding_wchar,
	mbfl_no_encoding_sjis,
	mbfl_filt_conv_common_ctor,
	mbfl_filt_conv_common_dtor,
	mbfl_filt_conv_wchar_sjis,
	mbfl_filt_conv_common_flush
};

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

#define SJIS_ENCODE(c1,c2,s1,s2)	\
		do {						\
			s1 = c1;				\
			s1--;					\
			s1 >>= 1;				\
			if ((c1) < 0x5f) {		\
				s1 += 0x71;			\
			} else {				\
				s1 += 0xb1;			\
			}						\
			s2 = c2;				\
			if ((c1) & 1) {			\
				if ((c2) < 0x60) {	\
					s2--;			\
				}					\
				s2 += 0x20;			\
			} else {				\
				s2 += 0x7e;			\
			}						\
		} while (0)

#define SJIS_DECODE(c1,c2,s1,s2)	\
		do {						\
			s1 = c1;				\
			if (s1 < 0xa0) {		\
				s1 -= 0x81;			\
			} else {				\
				s1 -= 0xc1;			\
			}						\
			s1 <<= 1;				\
			s1 += 0x21;				\
			s2 = c2;				\
			if (s2 < 0x9f) {		\
				if (s2 < 0x7f) {	\
					s2++;			\
				}					\
				s2 -= 0x20;			\
			} else {				\
				s1++;				\
				s2 -= 0x7e;			\
			}						\
		} while (0)


/*
 * SJIS => wchar
 */
int
mbfl_filt_conv_sjis_wchar(int c, mbfl_convert_filter *filter)
{
	int c1, s1, s2, w;

	switch (filter->status) {
	case 0:
		if (c >= 0 && c < 0x80) {	/* latin */
			CK((*filter->output_function)(c, filter->data));
		} else if (c > 0xa0 && c < 0xe0) {	/* kana */
			CK((*filter->output_function)(0xfec0 + c, filter->data));
		} else if (c > 0x80 && c < 0xfd && c != 0xa0) {	/* kanji first char */
			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:		/* kanji second char */
		filter->status = 0;
		c1 = filter->cache;
		if (c >= 0x40 && c <= 0xfc && c != 0x7f) {
			SJIS_DECODE(c1, c, s1, s2);
			w = (s1 - 0x21)*94 + s2 - 0x21;
			if (w >= 0 && w < jisx0208_ucs_table_size) {
				w = jisx0208_ucs_table[w];
			} else {
				w = 0;
			}
			if (w <= 0) {
				if (s1 < 0x7f && s2 < 0x7f) {
					w = (s1 << 8) | s2;
					w &= MBFL_WCSPLANE_MASK;
					w |= MBFL_WCSPLANE_JIS0208;
				} else {
					w = (c1 << 8) | c;
					w &= MBFL_WCSGROUP_MASK;
					w |= MBFL_WCSGROUP_THROUGH;
				}
			}
			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 => SJIS
 */
int
mbfl_filt_conv_wchar_sjis(int c, mbfl_convert_filter *filter)
{
	int c1, c2, s1, s2;

	s1 = 0;
	if (c >= ucs_a1_jis_table_min && c < ucs_a1_jis_table_max) {
		s1 = ucs_a1_jis_table[c - ucs_a1_jis_table_min];
	} else if (c >= ucs_a2_jis_table_min && c < ucs_a2_jis_table_max) {
		s1 = ucs_a2_jis_table[c - ucs_a2_jis_table_min];
	} else if (c >= ucs_i_jis_table_min && c < ucs_i_jis_table_max) {
		s1 = ucs_i_jis_table[c - ucs_i_jis_table_min];
	} else if (c >= ucs_r_jis_table_min && c < ucs_r_jis_table_max) {
		s1 = ucs_r_jis_table[c - ucs_r_jis_table_min];
	}
	if (s1 <= 0) {
		c1 = c & ~MBFL_WCSPLANE_MASK;
		if (c1 == MBFL_WCSPLANE_JIS0208) {
			s1 = c & MBFL_WCSPLANE_MASK;
		} else if (c == 0xa5) {		/* YEN SIGN */
			s1 = 0x216f;	/* FULLWIDTH YEN SIGN */
		} else if (c == 0x203e) {	/* OVER LINE */
			s1 = 0x2131;	/* FULLWIDTH MACRON */
		} else if (c == 0xff3c) {	/* FULLWIDTH REVERSE SOLIDUS */
			s1 = 0x2140;
		} else if (c == 0xff5e) {	/* FULLWIDTH TILDE */
			s1 = 0x2141;
		} else if (c == 0x2225) {	/* PARALLEL TO */
			s1 = 0x2142;
		} else if (c == 0xff0d) {	/* FULLWIDTH HYPHEN-MINUS */
			s1 = 0x215d;
		} else if (c == 0xffe0) {	/* FULLWIDTH CENT SIGN */
			s1 = 0x2171;
		} else if (c == 0xffe1) {	/* FULLWIDTH POUND SIGN */
			s1 = 0x2172;
		} else if (c == 0xffe2) {	/* FULLWIDTH NOT SIGN */
			s1 = 0x224c;
		}
		if (c == 0) {
			s1 = 0;
		} else if (s1 <= 0) {
			s1 = -1;
		}
	} else if (s1 >= 0x8080) {
		s1 = -1;
	}
	if (s1 >= 0) {
		if (s1 < 0x100) { /* latin or kana */
			CK((*filter->output_function)(s1, filter->data));
		} else { /* kanji */
			c1 = (s1 >> 8) & 0xff;
			c2 = s1 & 0xff;
			SJIS_ENCODE(c1, c2, s1, s2);
			CK((*filter->output_function)(s1, filter->data));
			CK((*filter->output_function)(s2, 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_sjis(int c, mbfl_identify_filter *filter)
{
	if (filter->status) {		/* kanji second char */
		if (c < 0x40 || c > 0xfc || c == 0x7f) {	/* bad */
		    filter->flag = 1;
		}
		filter->status = 0;
	} else if (c >= 0 && c < 0x80) {	/* latin  ok */
		;
	} else if (c > 0xa0 && c < 0xe0) {	/* kana  ok */
		;
	} else if (c > 0x80 && c < 0xf0 && c != 0xa0) {	/* kanji first char */
		filter->status = 1;
	} else {							/* bad */
		filter->flag = 1;
	}

	return c;
}

