/* $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/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"