/*      $NetBSD: citrus_big5.c,v 1.13 2011/05/23 14:53:46 joerg Exp $   */

/*-
 * Copyright (c)2002, 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.
 */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Paul Borman at Krystal Technologies.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/queue.h>
#include <sys/types.h>

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

#include "citrus_namespace.h"
#include "citrus_prop.h"
#include "citrus_types.h"
#include "citrus_bcs.h"
#include "citrus_module.h"
#include "citrus_stdenc.h"
#include "citrus_big5.h"

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

typedef struct {
        int      chlen;
        char     ch[2];
} _BIG5State;

typedef struct _BIG5Exclude {
        TAILQ_ENTRY(_BIG5Exclude)        entry;
        wint_t                           start;
        wint_t                           end;
} _BIG5Exclude;

typedef TAILQ_HEAD(_BIG5ExcludeList, _BIG5Exclude) _BIG5ExcludeList;

typedef struct {
        _BIG5ExcludeList         excludes;
        int                      cell[0x100];
} _BIG5EncodingInfo;

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

#define _FUNCNAME(m)                    _citrus_BIG5_##m
#define _ENCODING_INFO                  _BIG5EncodingInfo
#define _ENCODING_STATE                 _BIG5State
#define _ENCODING_MB_CUR_MAX(_ei_)      2
#define _ENCODING_IS_STATE_DEPENDENT    0
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)        0


static __inline void
/*ARGSUSED*/
_citrus_BIG5_init_state(_BIG5EncodingInfo * __restrict ei __unused,
    _BIG5State * __restrict s)
{

        memset(s, 0, sizeof(*s));
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_BIG5_pack_state(_BIG5EncodingInfo * __restrict ei __unused,
    void * __restrict pspriv,
    const _BIG5State * __restrict s)
{

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

static __inline void
/*ARGSUSED*/
_citrus_BIG5_unpack_state(_BIG5EncodingInfo * __restrict ei __unused,
    _BIG5State * __restrict s,
    const void * __restrict pspriv)
{

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

static __inline int
_citrus_BIG5_check(_BIG5EncodingInfo *ei, unsigned int c)
{

        return ((ei->cell[c & 0xFF] & 0x1) ? 2 : 1);
}

static __inline int
_citrus_BIG5_check2(_BIG5EncodingInfo *ei, unsigned int c)
{

        return ((ei->cell[c & 0xFF] & 0x2) ? 1 : 0);
}

static __inline int
_citrus_BIG5_check_excludes(_BIG5EncodingInfo *ei, wint_t c)
{
        _BIG5Exclude *exclude;

        TAILQ_FOREACH(exclude, &ei->excludes, entry) {
                if (c >= exclude->start && c <= exclude->end)
                        return (EILSEQ);
        }
        return (0);
}

static int
_citrus_BIG5_fill_rowcol(void * __restrict ctx, const char * __restrict s,
    uint64_t start, uint64_t end)
{
        _BIG5EncodingInfo *ei;
        uint64_t n;
        int i;

        if (start > 0xFF || end > 0xFF)
                return (EINVAL);
        ei = (_BIG5EncodingInfo *)ctx;
        i = strcmp("row", s) ? 1 : 0;
        i = 1 << i;
        for (n = start; n <= end; ++n)
                ei->cell[n & 0xFF] |= i;
        return (0);
}

static int
/*ARGSUSED*/
_citrus_BIG5_fill_excludes(void * __restrict ctx,
    const char * __restrict s __unused, uint64_t start, uint64_t end)
{
        _BIG5EncodingInfo *ei;
        _BIG5Exclude *exclude;

        if (start > 0xFFFF || end > 0xFFFF)
                return (EINVAL);
        ei = (_BIG5EncodingInfo *)ctx;
        exclude = TAILQ_LAST(&ei->excludes, _BIG5ExcludeList);
        if (exclude != NULL && (wint_t)start <= exclude->end)
                return (EINVAL);
        exclude = (void *)malloc(sizeof(*exclude));
        if (exclude == NULL)
                return (ENOMEM);
        exclude->start = (wint_t)start;
        exclude->end = (wint_t)end;
        TAILQ_INSERT_TAIL(&ei->excludes, exclude, entry);

        return (0);
}

static const _citrus_prop_hint_t root_hints[] = {
    _CITRUS_PROP_HINT_NUM("row", &_citrus_BIG5_fill_rowcol),
    _CITRUS_PROP_HINT_NUM("col", &_citrus_BIG5_fill_rowcol),
    _CITRUS_PROP_HINT_NUM("excludes", &_citrus_BIG5_fill_excludes),
    _CITRUS_PROP_HINT_END
};

static void
/*ARGSUSED*/
_citrus_BIG5_encoding_module_uninit(_BIG5EncodingInfo *ei)
{
        _BIG5Exclude *exclude;

        while ((exclude = TAILQ_FIRST(&ei->excludes)) != NULL) {
                TAILQ_REMOVE(&ei->excludes, exclude, entry);
                free(exclude);
        }
}

static int
/*ARGSUSED*/
_citrus_BIG5_encoding_module_init(_BIG5EncodingInfo * __restrict ei,
    const void * __restrict var, size_t lenvar)
{
        const char *s;
        int err;

        memset((void *)ei, 0, sizeof(*ei));
        TAILQ_INIT(&ei->excludes);

        if (lenvar > 0 && var != NULL) {
                s = _bcs_skip_ws_len((const char *)var, &lenvar);
                if (lenvar > 0 && *s != '\0') {
                        err = _citrus_prop_parse_variable(
                            root_hints, (void *)ei, s, lenvar);
                        if (err == 0)
                                return (0);

                        _citrus_BIG5_encoding_module_uninit(ei);
                        memset((void *)ei, 0, sizeof(*ei));
                        TAILQ_INIT(&ei->excludes);
                }
        }

        /* fallback Big5-1984, for backward compatibility. */
        _citrus_BIG5_fill_rowcol(ei, "row", 0xA1, 0xFE);
        _citrus_BIG5_fill_rowcol(ei, "col", 0x40, 0x7E);
        _citrus_BIG5_fill_rowcol(ei, "col", 0xA1, 0xFE);

        return (0);
}

static int
/*ARGSUSED*/
_citrus_BIG5_mbrtowc_priv(_BIG5EncodingInfo * __restrict ei,
    wchar_t * __restrict pwc,
    char ** __restrict s, size_t n,
    _BIG5State * __restrict psenc,
    size_t * __restrict nresult)
{
        wchar_t wchar;
        char *s0;
        int c, chlenbak;

        s0 = *s;

        if (s0 == NULL) {
                _citrus_BIG5_init_state(ei, psenc);
                *nresult = 0;
                return (0);
        }

        chlenbak = psenc->chlen;

        /* make sure we have the first byte in the buffer */
        switch (psenc->chlen) {
        case 0:
                if (n < 1)
                        goto restart;
                psenc->ch[0] = *s0++;
                psenc->chlen = 1;
                n--;
                break;
        case 1:
                break;
        default:
                /* illegal state */
                goto ilseq;
        }

        c = _citrus_BIG5_check(ei, psenc->ch[0] & 0xff);
        if (c == 0)
                goto ilseq;
        while (psenc->chlen < c) {
                if (n < 1) {
                        goto restart;
                }
                psenc->ch[psenc->chlen] = *s0++;
                psenc->chlen++;
                n--;
        }

        switch (c) {
        case 1:
                wchar = psenc->ch[0] & 0xff;
                break;
        case 2:
                if (!_citrus_BIG5_check2(ei, psenc->ch[1] & 0xff))
                        goto ilseq;
                wchar = ((psenc->ch[0] & 0xff) << 8) | (psenc->ch[1] & 0xff);
                break;
        default:
                /* illegal state */
                goto ilseq;
        }

        if (_citrus_BIG5_check_excludes(ei, (wint_t)wchar) != 0)
                goto ilseq;

        *s = s0;
        psenc->chlen = 0;
        if (pwc)
                *pwc = wchar;
        *nresult = wchar ? c - chlenbak : 0;

        return (0);

ilseq:
        psenc->chlen = 0;
        *nresult = (size_t)-1;
        return (EILSEQ);

restart:
        *s = s0;
        *nresult = (size_t)-2;
        return (0);
}

static int
/*ARGSUSED*/
_citrus_BIG5_wcrtomb_priv(_BIG5EncodingInfo * __restrict ei,
    char * __restrict s,
    size_t n, wchar_t wc, _BIG5State * __restrict psenc __unused,
    size_t * __restrict nresult)
{
        size_t l;
        int ret;

        /* check invalid sequence */
        if (wc & ~0xffff ||
            _citrus_BIG5_check_excludes(ei, (wint_t)wc) != 0) {
                ret = EILSEQ;
                goto err;
        }

        if (wc & 0x8000) {
                if (_citrus_BIG5_check(ei, (wc >> 8) & 0xff) != 2 ||
                    !_citrus_BIG5_check2(ei, wc & 0xff)) {
                        ret = EILSEQ;
                        goto err;
                }
                l = 2;
        } else {
                if (wc & ~0xff || !_citrus_BIG5_check(ei, wc & 0xff)) {
                        ret = EILSEQ;
                        goto err;
                }
                l = 1;
        }

        if (n < l) {
                /* bound check failure */
                ret = E2BIG;
                goto err;
        }

        if (l == 2) {
                s[0] = (wc >> 8) & 0xff;
                s[1] = wc & 0xff;
        } else
                s[0] = wc & 0xff;

        *nresult = l;

        return (0);

err:
        *nresult = (size_t)-1;
        return (ret);
}

static __inline int
/*ARGSUSED*/
_citrus_BIG5_stdenc_wctocs(_BIG5EncodingInfo * __restrict ei __unused,
    _csid_t * __restrict csid,
    _index_t * __restrict idx, wchar_t wc)
{

        *csid = (wc < 0x100) ? 0 : 1;
        *idx = (_index_t)wc;

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_BIG5_stdenc_cstowc(_BIG5EncodingInfo * __restrict ei __unused,
    wchar_t * __restrict wc,
    _csid_t csid, _index_t idx)
{

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

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_BIG5_stdenc_get_state_desc_generic(_BIG5EncodingInfo * __restrict ei __unused,
    _BIG5State * __restrict psenc,
    int * __restrict rstate)
{

        *rstate = (psenc->chlen == 0) ? _STDENC_SDGEN_INITIAL :
            _STDENC_SDGEN_INCOMPLETE_CHAR;
        return (0);
}

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

_CITRUS_STDENC_DECLS(BIG5);
_CITRUS_STDENC_DEF_OPS(BIG5);

#include "citrus_stdenc_template.h"