/* $NetBSD: citrus_dechanyu.c,v 1.4 2011/11/19 18:20:13 tnozaki Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2007 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 <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_bcs.h"
#include "citrus_module.h"
#include "citrus_stdenc.h"
#include "citrus_dechanyu.h"

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

typedef struct {
        size_t   chlen;
        char     ch[4];
} _DECHanyuState;

typedef struct {
        int      dummy;
} _DECHanyuEncodingInfo;

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

#define _FUNCNAME(m)                    __CONCAT(_citrus_DECHanyu_,m)
#define _ENCODING_INFO                  _DECHanyuEncodingInfo
#define _ENCODING_STATE                 _DECHanyuState
#define _ENCODING_MB_CUR_MAX(_ei_)              4
#define _ENCODING_IS_STATE_DEPENDENT            0
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)        0

static __inline void
/*ARGSUSED*/
_citrus_DECHanyu_init_state(_DECHanyuEncodingInfo * __restrict ei __unused,
    _DECHanyuState * __restrict psenc)
{

        psenc->chlen = 0;
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_DECHanyu_pack_state(_DECHanyuEncodingInfo * __restrict ei __unused,
    void * __restrict pspriv, const _DECHanyuState * __restrict psenc)
{

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

static __inline void
/*ARGSUSED*/
_citrus_DECHanyu_unpack_state(_DECHanyuEncodingInfo * __restrict ei __unused,
    _DECHanyuState * __restrict psenc,
    const void * __restrict pspriv)
{

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

static void
/*ARGSUSED*/
_citrus_DECHanyu_encoding_module_uninit(_DECHanyuEncodingInfo *ei __unused)
{

        /* ei may be null */
}

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

        /* ei may be null */
        return (0);
}

static __inline bool
is_singlebyte(int c)
{

        return (c <= 0x7F);
}

static __inline bool
is_leadbyte(int c)
{

        return (c >= 0xA1 && c <= 0xFE);
}

static __inline bool
is_trailbyte(int c)
{

        c &= ~0x80;
        return (c >= 0x21 && c <= 0x7E);
}

static __inline bool
is_hanyu1(int c)
{

        return (c == 0xC2);
}

static __inline bool
is_hanyu2(int c)
{

        return (c == 0xCB);
}

#define HANYUBIT        0xC2CB0000

static __inline bool
is_94charset(int c)
{

        return (c >= 0x21 && c <= 0x7E);
}

static int
/*ARGSUSED*/
_citrus_DECHanyu_mbrtowc_priv(_DECHanyuEncodingInfo * __restrict ei,
    wchar_t * __restrict pwc, char ** __restrict s, size_t n,
    _DECHanyuState * __restrict psenc, size_t * __restrict nresult)
{
        char *s0;
        wchar_t wc;
        int ch;

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

        wc = (wchar_t)0;
        switch (psenc->chlen) {
        case 0:
                if (n-- < 1)
                        goto restart;
                ch = *s0++ & 0xFF;
                if (is_singlebyte(ch)) {
                        if (pwc != NULL)
                                *pwc = (wchar_t)ch;
                        *nresult = (size_t)((ch == 0) ? 0 : 1);
                        *s = s0;
                        return (0);
                }
                if (!is_leadbyte(ch))
                        goto ilseq;
                psenc->ch[psenc->chlen++] = ch;
                break;
        case 1:
                ch = psenc->ch[0] & 0xFF;
                if (!is_leadbyte(ch))
                        return (EINVAL);
                break;
        case 2: case 3:
                ch = psenc->ch[0] & 0xFF;
                if (is_hanyu1(ch)) {
                        ch = psenc->ch[1] & 0xFF;
                        if (is_hanyu2(ch)) {
                                wc |= (wchar_t)HANYUBIT;
                                break;
                        }
                }
        /*FALLTHROUGH*/
        default:
                return (EINVAL);
        }

        switch (psenc->chlen) {
        case 1:
                if (is_hanyu1(ch)) {
                        if (n-- < 1)
                                goto restart;
                        ch = *s0++ & 0xFF;
                        if (!is_hanyu2(ch))
                                goto ilseq;
                        psenc->ch[psenc->chlen++] = ch;
                        wc |= (wchar_t)HANYUBIT;
                        if (n-- < 1)
                                goto restart;
                        ch = *s0++ & 0xFF;
                        if (!is_leadbyte(ch))
                                goto ilseq;
                        psenc->ch[psenc->chlen++] = ch;
                }
                break;
        case 2:
                if (n-- < 1)
                        goto restart;
                ch = *s0++ & 0xFF;
                if (!is_leadbyte(ch))
                        goto ilseq;
                psenc->ch[psenc->chlen++] = ch;
                break;
        case 3:
                ch = psenc->ch[2] & 0xFF;
                if (!is_leadbyte(ch))
                        return (EINVAL);
        }
        if (n-- < 1)
                goto restart;
        wc |= (wchar_t)(ch << 8);
        ch = *s0++ & 0xFF;
        if (!is_trailbyte(ch))
                goto ilseq;
        wc |= (wchar_t)ch;
        if (pwc != NULL)
                *pwc = wc;
        *nresult = (size_t)(s0 - *s);
        *s = s0;
        psenc->chlen = 0;

        return (0);

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

ilseq:
        *nresult = (size_t)-1;
        return (EILSEQ);
}

static int
/*ARGSUSED*/
_citrus_DECHanyu_wcrtomb_priv(_DECHanyuEncodingInfo * __restrict ei __unused,
    char * __restrict s, size_t n, wchar_t wc,
    _DECHanyuState * __restrict psenc, size_t * __restrict nresult)
{
        int ch;

        if (psenc->chlen != 0)
                return (EINVAL);

        /* XXX: assume wchar_t as int */
        if ((uint32_t)wc <= 0x7F) {
                ch = wc & 0xFF;
        } else {
                if ((uint32_t)wc > 0xFFFF) {
                        if ((wc & ~0xFFFF) != (wchar_t)HANYUBIT)
                                goto ilseq;
                        psenc->ch[psenc->chlen++] = (wc >> 24) & 0xFF;
                        psenc->ch[psenc->chlen++] = (wc >> 16) & 0xFF;
                        wc &= 0xFFFF;
                }
                ch = (wc >> 8) & 0xFF;
                if (!is_leadbyte(ch))
                        goto ilseq;
                psenc->ch[psenc->chlen++] = ch;
                ch = wc & 0xFF;
                if (!is_trailbyte(ch))
                        goto ilseq;
        }
        psenc->ch[psenc->chlen++] = ch;
        if (n < psenc->chlen) {
                *nresult = (size_t)-1;
                return (E2BIG);
        }
        memcpy(s, psenc->ch, psenc->chlen);
        *nresult = psenc->chlen;
        psenc->chlen = 0;

        return (0);

ilseq:
        *nresult = (size_t)-1;
        return (EILSEQ);
}

static __inline int
/*ARGSUSED*/
_citrus_DECHanyu_stdenc_wctocs(_DECHanyuEncodingInfo * __restrict ei __unused,
    _csid_t * __restrict csid, _index_t * __restrict idx, wchar_t wc)
{
        wchar_t mask;
        int plane;

        plane = 0;
        mask = 0x7F;
        /* XXX: assume wchar_t as int */
        if ((uint32_t)wc > 0x7F) {
                if ((uint32_t)wc > 0xFFFF) {
                        if ((wc & ~0xFFFF) != (wchar_t)HANYUBIT)
                                return (EILSEQ);
                        plane += 2;
                }
                if (!is_leadbyte((wc >> 8) & 0xFF) ||
                    !is_trailbyte(wc & 0xFF))
                        return (EILSEQ);
                plane += (wc & 0x80) ? 1 : 2;
                mask |= 0x7F00;
        }
        *csid = plane;
        *idx = (_index_t)(wc & mask);

        return (0);
}

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

        if (csid == 0) {
                if (idx > 0x7F)
                        return (EILSEQ);
        } else if (csid <= 4) {
                if (!is_94charset(idx >> 8))
                        return (EILSEQ);
                if (!is_94charset(idx & 0xFF))
                        return (EILSEQ);
                if (csid % 2)
                        idx |= 0x80;
                idx |= 0x8000;
                if (csid > 2)
                        idx |= HANYUBIT;
        } else
                return (EILSEQ);
        *wc = (wchar_t)idx;
        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_DECHanyu_stdenc_get_state_desc_generic(
    _DECHanyuEncodingInfo * __restrict ei __unused,
    _DECHanyuState * __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(DECHanyu);
_CITRUS_STDENC_DEF_OPS(DECHanyu);

#include "citrus_stdenc_template.h"