/* $FreeBSD$ */
/* $NetBSD: citrus_zw.c,v 1.4 2008/06/14 16:01:08 tnozaki Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2004, 2006 Citrus Project,
 * 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 <sys/cdefs.h>
#include <sys/types.h>

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_module.h"
#include "citrus_stdenc.h"
#include "citrus_zw.h"

/* ----------------------------------------------------------------------
 * private stuffs used by templates
 */

typedef struct {
	int	 dummy;
} _ZWEncodingInfo;

typedef enum {
	NONE, AMBIGIOUS, ASCII, GB2312
} _ZWCharset;

typedef struct {
	_ZWCharset	 charset;
	int		 chlen;
	char		 ch[4];
} _ZWState;

#define _CEI_TO_EI(_cei_)		(&(_cei_)->ei)
#define _CEI_TO_STATE(_cei_, _func_)	(_cei_)->states.s_##_func_

#define _FUNCNAME(m)			_citrus_ZW_##m
#define _ENCODING_INFO			_ZWEncodingInfo
#define _ENCODING_STATE			_ZWState
#define _ENCODING_MB_CUR_MAX(_ei_)	MB_LEN_MAX
#define _ENCODING_IS_STATE_DEPENDENT		1
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)	((_ps_)->charset != NONE)

static __inline void
/*ARGSUSED*/
_citrus_ZW_init_state(_ZWEncodingInfo * __restrict ei __unused,
    _ZWState * __restrict psenc)
{

	psenc->chlen = 0;
	psenc->charset = NONE;
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_ZW_pack_state(_ZWEncodingInfo * __restrict ei __unused,
    void *__restrict pspriv, const _ZWState * __restrict psenc)
{

	memcpy(pspriv, (const void *)psenc, sizeof(*psenc));
}

static __inline void
/*ARGSUSED*/
_citrus_ZW_unpack_state(_ZWEncodingInfo * __restrict ei __unused,
    _ZWState * __restrict psenc, const void * __restrict pspriv)
{

	memcpy((void *)psenc, pspriv, sizeof(*psenc));
}
#endif

static int
_citrus_ZW_mbrtowc_priv(_ZWEncodingInfo * __restrict ei,
    wchar_t * __restrict pwc, char **__restrict s, size_t n,
    _ZWState * __restrict psenc, size_t * __restrict nresult)
{
	char *s0;
	wchar_t  wc;
	int ch, len;

	if (*s == NULL) {
		_citrus_ZW_init_state(ei, psenc);
		*nresult = (size_t)_ENCODING_IS_STATE_DEPENDENT;
		return (0);
	}
	s0 = *s;
	len = 0;

#define	STORE				\
do {					\
	if (n-- < 1) {			\
		*nresult = (size_t)-2;	\
		*s = s0;		\
		return (0);		\
	}				\
	ch = (unsigned char)*s0++;	\
	if (len++ > MB_LEN_MAX || ch > 0x7F)\
		goto ilseq;		\
	psenc->ch[psenc->chlen++] = ch;	\
} while (/*CONSTCOND*/0)

loop:
	switch (psenc->charset) {
	case ASCII:
		switch (psenc->chlen) {
		case 0:
			STORE;
			switch (psenc->ch[0]) {
			case '\0': case '\n':
				psenc->charset = NONE;
			}
		/*FALLTHROUGH*/
		case 1:
			break;
		default:
			return (EINVAL);
		}
		ch = (unsigned char)psenc->ch[0];
		if (ch > 0x7F)
			goto ilseq;
		wc = (wchar_t)ch;
		psenc->chlen = 0;
		break;
	case NONE:
		if (psenc->chlen != 0)
			return (EINVAL);
		STORE;
		ch = (unsigned char)psenc->ch[0];
		if (ch != 'z') {
			if (ch != '\n' && ch != '\0')
				psenc->charset = ASCII;
			wc = (wchar_t)ch;
			psenc->chlen = 0;
			break;
		}
		psenc->charset = AMBIGIOUS;
		psenc->chlen = 0;
	/* FALLTHROUGH */
	case AMBIGIOUS:
		if (psenc->chlen != 0)
			return (EINVAL);
		STORE;
		if (psenc->ch[0] != 'W') {
			psenc->charset = ASCII;
			wc = L'z';
			break;
		}
		psenc->charset = GB2312;
		psenc->chlen = 0;
	/* FALLTHROUGH */
	case GB2312:
		switch (psenc->chlen) {
		case 0:
			STORE;
			ch = (unsigned char)psenc->ch[0];
			if (ch == '\0') {
				psenc->charset = NONE;
				wc = (wchar_t)ch;
				psenc->chlen = 0;
				break;
			} else if (ch == '\n') {
				psenc->charset = NONE;
				psenc->chlen = 0;
				goto loop;
			}
		/*FALLTHROUGH*/
		case 1:
			STORE;
			if (psenc->ch[0] == ' ') {
				ch = (unsigned char)psenc->ch[1];
				wc = (wchar_t)ch;
				psenc->chlen = 0;
				break;
			} else if (psenc->ch[0] == '#') {
				ch = (unsigned char)psenc->ch[1];
				if (ch == '\n') {
					psenc->charset = NONE;
					wc = (wchar_t)ch;
					psenc->chlen = 0;
					break;
				} else if (ch == ' ') {
					wc = (wchar_t)ch;
					psenc->chlen = 0;
					break;
				}
			}
			ch = (unsigned char)psenc->ch[0];
			if (ch < 0x21 || ch > 0x7E)
				goto ilseq;
			wc = (wchar_t)(ch << 8);
			ch = (unsigned char)psenc->ch[1];
			if (ch < 0x21 || ch > 0x7E) {
ilseq:
				*nresult = (size_t)-1;
				return (EILSEQ);
			}
			wc |= (wchar_t)ch;
			psenc->chlen = 0;
			break;
		default:
			return (EINVAL);
		}
		break;
	default:
		return (EINVAL);
	}
	if (pwc != NULL)
		*pwc = wc;

	*nresult = (size_t)(wc == 0 ? 0 : len);
	*s = s0;

	return (0);
}

static int
/*ARGSUSED*/
_citrus_ZW_wcrtomb_priv(_ZWEncodingInfo * __restrict ei __unused,
    char *__restrict s, size_t n, wchar_t wc,
    _ZWState * __restrict psenc, size_t * __restrict nresult)
{
	int ch;

	if (psenc->chlen != 0)
		return (EINVAL);
	if ((uint32_t)wc <= 0x7F) {
		ch = (unsigned char)wc;
		switch (psenc->charset) {
		case NONE:
			if (ch == '\0' || ch == '\n')
				psenc->ch[psenc->chlen++] = ch;
			else {
				if (n < 4)
					return (E2BIG);
				n -= 4;
				psenc->ch[psenc->chlen++] = 'z';
				psenc->ch[psenc->chlen++] = 'W';
				psenc->ch[psenc->chlen++] = ' ';
				psenc->ch[psenc->chlen++] = ch;
				psenc->charset = GB2312;
			}
			break;
		case GB2312:
			if (n < 2)
				return (E2BIG);
			n -= 2;
			if (ch == '\0') {
				psenc->ch[psenc->chlen++] = '\n';
				psenc->ch[psenc->chlen++] = '\0';
				psenc->charset = NONE;
			} else if (ch == '\n') {
				psenc->ch[psenc->chlen++] = '#';
				psenc->ch[psenc->chlen++] = '\n';
				psenc->charset = NONE;
			} else {
				psenc->ch[psenc->chlen++] = ' ';
				psenc->ch[psenc->chlen++] = ch;
			}
			break;
		default:
			return (EINVAL);
		}
	} else if ((uint32_t)wc <= 0x7E7E) {
		switch (psenc->charset) {
		case NONE:
			if (n < 2)
				return (E2BIG);
			n -= 2;
			psenc->ch[psenc->chlen++] = 'z';
			psenc->ch[psenc->chlen++] = 'W';
			psenc->charset = GB2312;
		/* FALLTHROUGH*/
		case GB2312:
			if (n < 2)
				return (E2BIG);
			n -= 2;
			ch = (wc >> 8) & 0xFF;
			if (ch < 0x21 || ch > 0x7E)
				goto ilseq;
			psenc->ch[psenc->chlen++] = ch;
			ch = wc & 0xFF;
			if (ch < 0x21 || ch > 0x7E)
				goto ilseq;
			psenc->ch[psenc->chlen++] = ch;
			break;
		default:
			return (EINVAL);
		}
	} else {
ilseq:
		*nresult = (size_t)-1;
		return (EILSEQ);
	}
	memcpy(s, psenc->ch, psenc->chlen);
	*nresult = psenc->chlen;
	psenc->chlen = 0;

	return (0);
}

static int
/*ARGSUSED*/
_citrus_ZW_put_state_reset(_ZWEncodingInfo * __restrict ei __unused,
    char * __restrict s, size_t n, _ZWState * __restrict psenc,
    size_t * __restrict nresult)
{

	if (psenc->chlen != 0)
		return (EINVAL);
	switch (psenc->charset) {
	case GB2312:
		if (n-- < 1)
			return (E2BIG);
		psenc->ch[psenc->chlen++] = '\n';
		psenc->charset = NONE;
	/*FALLTHROUGH*/
	case NONE:
		*nresult = psenc->chlen;
		if (psenc->chlen > 0) {
			memcpy(s, psenc->ch, psenc->chlen);
			psenc->chlen = 0;
		}
		break;
	default:
		return (EINVAL);
	}

	return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_ZW_stdenc_get_state_desc_generic(_ZWEncodingInfo * __restrict ei __unused,
    _ZWState * __restrict psenc, int * __restrict rstate)
{

	switch (psenc->charset) {
	case NONE:
		if (psenc->chlen != 0)
			return (EINVAL);
		*rstate = _STDENC_SDGEN_INITIAL;
		break;
	case AMBIGIOUS:
		if (psenc->chlen != 0)
			return (EINVAL);
		*rstate = _STDENC_SDGEN_INCOMPLETE_SHIFT;
		break;
	case ASCII:
	case GB2312:
		switch (psenc->chlen) {
		case 0:
			*rstate = _STDENC_SDGEN_STABLE;
			break;
		case 1:
			*rstate = (psenc->ch[0] == '#') ?
			    _STDENC_SDGEN_INCOMPLETE_SHIFT :
			    _STDENC_SDGEN_INCOMPLETE_CHAR;
			break;
		default:
			return (EINVAL);
		}
		break;
	default:
		return (EINVAL);
	}
	return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_ZW_stdenc_wctocs(_ZWEncodingInfo * __restrict ei __unused,
    _csid_t * __restrict csid, _index_t * __restrict idx, wchar_t wc)
{

	*csid = (_csid_t)(wc <= (wchar_t)0x7FU) ? 0 : 1;
	*idx = (_index_t)wc;

	return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_ZW_stdenc_cstowc(_ZWEncodingInfo * __restrict ei __unused,
    wchar_t * __restrict wc, _csid_t csid, _index_t idx)
{

	switch (csid) {
	case 0: case 1:
		break;
	default:
		return (EINVAL);
	}
	*wc = (wchar_t)idx;

	return (0);
}

static void
/*ARGSUSED*/
_citrus_ZW_encoding_module_uninit(_ZWEncodingInfo *ei __unused)
{

}

static int
/*ARGSUSED*/
_citrus_ZW_encoding_module_init(_ZWEncodingInfo * __restrict ei __unused,
    const void *__restrict var __unused, size_t lenvar __unused)
{

	return (0);
}

/* ----------------------------------------------------------------------
 * public interface for stdenc
 */

_CITRUS_STDENC_DECLS(ZW);
_CITRUS_STDENC_DEF_OPS(ZW);

#include "citrus_stdenc_template.h"