/*-
 * 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 "dcmtk/config/osconfig.h"
#include "citrus_dechanyu.h"

#include <sys/types.h>
#ifndef __CONCAT
#define __CONCAT(x,y) x ## y
#endif

#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_bcs.h"
#include "citrus_types.h"
#include "citrus_module.h"
#include "citrus_stdenc.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 * ei ,
    _DECHanyuState * psenc)
{
    (void) ei;
    psenc->chlen = 0;
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_DECHanyu_pack_state(_DECHanyuEncodingInfo * ei ,
    void * pspriv, const _DECHanyuState * psenc)
{
    (void) ei;
    memcpy(pspriv, (const void *)psenc, sizeof(*psenc));
}

static __inline void
/*ARGSUSED*/
_citrus_DECHanyu_unpack_state(_DECHanyuEncodingInfo * ei ,
    _DECHanyuState * psenc,
    const void * pspriv)
{
    (void) ei;
    memcpy((void *)psenc, pspriv, sizeof(*psenc));
}
#endif

static void
/*ARGSUSED*/
_citrus_DECHanyu_encoding_module_uninit(_DECHanyuEncodingInfo *ei )
{
    /* ei may be null */
    (void) ei;
}

static int
/*ARGSUSED*/
_citrus_DECHanyu_encoding_module_init(_DECHanyuEncodingInfo * ei ,
    const void * var , size_t lenvar )
{
    /* ei may be null */
    (void) ei;
    (void) var;
    (void) lenvar;
    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 * ei,
    _citrus_wc_t * pwc, char ** s, size_t n,
    _DECHanyuState * psenc, size_t * nresult)
{
    char *s0;
    _citrus_wc_t wc;
    int ch;

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

    wc = (_citrus_wc_t)0;
    switch (psenc->chlen) {
    case 0:
        if (n-- < 1)
            goto restart;
        ch = *s0++ & 0xFF;
        if (is_singlebyte(ch)) {
            if (pwc != NULL)
                *pwc = (_citrus_wc_t)ch;
            *nresult = (size_t)((ch == 0) ? 0 : 1);
            *s = s0;
            return (0);
        }
        if (!is_leadbyte(ch))
            goto ilseq;
        psenc->ch[psenc->chlen++] = (char) 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 |= (_citrus_wc_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++] = (char) ch;
            wc |= (_citrus_wc_t)HANYUBIT;
            if (n-- < 1)
                goto restart;
            ch = *s0++ & 0xFF;
            if (!is_leadbyte(ch))
                goto ilseq;
            psenc->ch[psenc->chlen++] = (char) ch;
        }
        break;
    case 2:
        if (n-- < 1)
            goto restart;
        ch = *s0++ & 0xFF;
        if (!is_leadbyte(ch))
            goto ilseq;
        psenc->ch[psenc->chlen++] = (char) ch;
        break;
    case 3:
        ch = psenc->ch[2] & 0xFF;
        if (!is_leadbyte(ch))
            return (EINVAL);
    }
    if (n-- < 1)
        goto restart;
    wc |= (_citrus_wc_t)(ch << 8);
    ch = *s0++ & 0xFF;
    if (!is_trailbyte(ch))
        goto ilseq;
    wc |= (_citrus_wc_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 * ei ,
    char * s, size_t n, _citrus_wc_t wc,
    _DECHanyuState * psenc, size_t * nresult)
{
    int ch;
    (void) ei;

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

    /* XXX: assume _citrus_wc_t as int */
    if ((uint32_t)wc <= 0x7F) {
        ch = wc & 0xFF;
    } else {
        if ((uint32_t)wc > 0xFFFF) {
            if ((wc & ~0xFFFF) != (_citrus_wc_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++] = (char) ch;
        ch = wc & 0xFF;
        if (!is_trailbyte(ch))
            goto ilseq;
    }
    psenc->ch[psenc->chlen++] = (char) 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 * ei ,
    _citrus_csid_t * csid, _citrus_index_t * idx, _citrus_wc_t wc)
{
    _citrus_wc_t mask;
    int plane;
    (void) ei;

    plane = 0;
    mask = 0x7F;
    /* XXX: assume _citrus_wc_t as int */
    if ((uint32_t)wc > 0x7F) {
        if ((uint32_t)wc > 0xFFFF) {
            if ((wc & ~0xFFFF) != (_citrus_wc_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 = (_citrus_index_t)(wc & mask);

    return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_DECHanyu_stdenc_cstowc(_DECHanyuEncodingInfo * ei ,
    _citrus_wc_t * wc, _citrus_csid_t csid, _citrus_index_t idx)
{
    (void) ei;

    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 = (_citrus_wc_t)idx;
    return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_DECHanyu_stdenc_get_state_desc_generic(
    _DECHanyuEncodingInfo * ei ,
    _DECHanyuState * psenc, int * rstate)
{
    (void) ei;

    *rstate = (psenc->chlen == 0)
        ? _CITRUS_STDENC_SDGEN_INITIAL
        : _CITRUS_STDENC_SDGEN_INCOMPLETE_CHAR;
    return (0);
}

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

_CITRUS_STDENC_DECLS(DECHanyu);
_CITRUS_STDENC_DEF_OPS(DECHanyu);

#include "citrus_stdenc_template.h"
