/* $NetBSD: citrus_johab.c,v 1.7 2019/07/08 06:45:01 mlelstv Exp $ */

/*-
 * Copyright (c)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>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: citrus_johab.c,v 1.7 2019/07/08 06:45:01 mlelstv Exp $");
#endif /* LIBC_SCCS and not lint */

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

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_bcs.h"
#include "citrus_module.h"
#include "citrus_ctype.h"
#include "citrus_stdenc.h"
#include "citrus_johab.h"

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

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

typedef struct {
        int dummy;
} _JOHABEncodingInfo;

typedef struct {
        _JOHABEncodingInfo      ei;
        struct {
                /* for future multi-locale facility */
                _JOHABState     s_mblen;
                _JOHABState     s_mbrlen;
                _JOHABState     s_mbrtowc;
                _JOHABState     s_mbtowc;
                _JOHABState     s_mbsrtowcs;
                _JOHABState     s_mbsnrtowcs;
                _JOHABState     s_wcrtomb;
                _JOHABState     s_wcsrtombs;
                _JOHABState     s_wcsnrtombs;
                _JOHABState     s_wctomb;
        } states;
} _JOHABCTypeInfo;

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

#define _FUNCNAME(m)                    _citrus_JOHAB_##m
#define _ENCODING_INFO                  _JOHABEncodingInfo
#define _CTYPE_INFO                     _JOHABCTypeInfo
#define _ENCODING_STATE                 _JOHABState
#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_JOHAB_init_state(_JOHABEncodingInfo * __restrict ei,
        _JOHABState * __restrict psenc)
{
        /* ei may be null */
        _DIAGASSERT(psenc != NULL);

        psenc->chlen = 0;
}

static __inline void
/*ARGSUSED*/
_citrus_JOHAB_pack_state(_JOHABEncodingInfo * __restrict ei,
        void * __restrict pspriv,
        const _JOHABState * __restrict psenc)
{
        /* ei may be null */
        _DIAGASSERT(pspriv != NULL);
        _DIAGASSERT(psenc != NULL);

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

static __inline void
/*ARGSUSED*/
_citrus_JOHAB_unpack_state(_JOHABEncodingInfo * __restrict ei,
        _JOHABState * __restrict psenc,
        const void * __restrict pspriv)
{
        /* ei may be null */
        _DIAGASSERT(psenc != NULL);
        _DIAGASSERT(pspriv != NULL);

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

static void
/*ARGSUSED*/
_citrus_JOHAB_encoding_module_uninit(_JOHABEncodingInfo *ei)
{
        /* ei may be null */
}

static int
/*ARGSUSED*/
_citrus_JOHAB_encoding_module_init(_JOHABEncodingInfo * __restrict ei,
        const void * __restrict var, size_t lenvar)
{
        /* ei may be null */
        return 0;
}

static __inline int
ishangul(int l, int t)
{

        return (l >= 0x84 && l <= 0xD3) &&
              ((t >= 0x41 && t <= 0x7E) || (t >= 0x81 && t <= 0xFE));
}

static __inline int
isuda(int l, int t)
{
        return (l == 0xD8) &&
               ((t >= 0x31 && t <= 0x7E) || (t >= 0x91 && t <= 0xFE));
}

static __inline int
ishanja(int l, int t)
{
        return ((l >= 0xD9 && l <= 0xDE) || (l >= 0xE0 && l <= 0xF9)) &&
               ((t >= 0x31 && t <= 0x7E) || (t >= 0x91 && t <= 0xFE));
}

static int
/*ARGSUSED*/
_citrus_JOHAB_mbrtowc_priv(_JOHABEncodingInfo * __restrict ei,
        wchar_t * __restrict pwc, const char ** __restrict s, size_t n,
        _JOHABState * __restrict psenc, size_t * __restrict nresult)
{
        const char *s0;
        int l, t;

        /* ei may be unused */
        _DIAGASSERT(s != NULL);
        _DIAGASSERT(psenc != NULL);
        _DIAGASSERT(nresult != 0);

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

        switch (psenc->chlen) {
        case 0:
                if (n-- < 1)
                        goto restart;
                l = *s0++ & 0xFF;
                if (l <= 0x7F) {
                        if (pwc != NULL)
                                *pwc = (wchar_t)l;
                        *nresult = (l == 0) ? 0 : 1;
                        *s = s0;
                        return 0;
                }
                psenc->ch[psenc->chlen++] = l;
                break;
        case 1:
                l = psenc->ch[0] & 0xFF;
                break;
        default:
                return EINVAL;
        }
        if (n-- < 1) {
restart:
                *nresult = (size_t)-2;
                *s = s0;
                return 0;
        }
        t = *s0++ & 0xFF;
        if (!ishangul(l, t) && !isuda(l, t) && !ishanja(l, t)) {
                *nresult = (size_t)-1;
                return EILSEQ;
        }
        if (pwc != NULL)
                *pwc = (wchar_t)(l << 8 | t);
        *nresult = s0 - *s;
        *s = s0;
        psenc->chlen = 0;

        return 0;
}

static int
/*ARGSUSED*/
_citrus_JOHAB_wcrtomb_priv(_JOHABEncodingInfo * __restrict ei,
        char * __restrict s, size_t n, wchar_t wc,
        _JOHABState * __restrict psenc, size_t * __restrict nresult)
{
        int l, t;

        /* ei may be unused */
        _DIAGASSERT(s != NULL);
        _DIAGASSERT(psenc != NULL);
        _DIAGASSERT(nresult != NULL);

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

        /* XXX assume wchar_t as int */
        if ((uint32_t)wc <= 0x7F) {
                if (n < 1)
                        goto e2big;
                *s = wc & 0xFF;
                *nresult = 1;
        } else if ((uint32_t)wc <= 0xFFFF) {
                if (n < 2) {
e2big:
                        *nresult = (size_t)-1;
                        return E2BIG;
                }
                l = (wc >> 8) & 0xFF;
                t = wc & 0xFF;
                if (!ishangul(l, t) && !isuda(l, t) && !ishanja(l, t))
                        goto ilseq;
                *s++ = l;
                *s = t;
                *nresult = 2;
        } else {
ilseq:
                *nresult = (size_t)-1;
                return EILSEQ;
        }
        return 0;

}

static __inline int
/*ARGSUSED*/
_citrus_JOHAB_stdenc_wctocs(_JOHABEncodingInfo * __restrict ei,
        _csid_t * __restrict csid, _index_t * __restrict idx, wchar_t wc)
{
        int m, l, t, linear;

        /* ei may be unused */
        _DIAGASSERT(csid != NULL);
        _DIAGASSERT(idx != NULL);

        /* XXX assume wchar_t as int */
        if ((uint32_t)wc <= 0x7F) {
                *idx = (_index_t)wc;
                *csid = 0;
        } else if ((uint32_t)wc <= 0xFFFF) {
                l = (wc >> 8) & 0xFF;
                t = wc & 0xFF;
                if (ishangul(l, t) || isuda(l, t)) {
                        *idx = (_index_t)wc;
                        *csid = 1;
                } else {
                        if (l >= 0xD9 && l <= 0xDE) {
                                linear = l - 0xD9;
                                m = 0x21;
                        } else if (l >= 0xE0 && l <= 0xF9) {
                                linear = l - 0xE0;
                                m = 0x4A;
                        } else {
                                return EILSEQ;
                        }
                        linear *= 188;
                        if (t >= 0x31 && t <= 0x7E) {
                                linear += t - 0x31;
                        } else if (t >= 0x91 && t <= 0xFE) {
                                linear += t - 0x43;
                        } else {
                                return EILSEQ;
                        }
                        l = (linear / 94) + m;
                        t = (linear % 94) + 0x21;
                        *idx = (_index_t)((l << 8) | t);
                        *csid = 2;
                }
        } else {
                return EILSEQ;
        }
        return 0;
}

static __inline int
/*ARGSUSED*/
_citrus_JOHAB_stdenc_cstowc(_JOHABEncodingInfo * __restrict ei,
        wchar_t * __restrict wc, _csid_t csid, _index_t idx)
{
        int m, n, l, t, linear;

        /* ei may be unused */
        _DIAGASSERT(wc != NULL);

        switch (csid) {
        case 0:
        case 1:
                *wc = (wchar_t)idx;
                break;
        case 2:
                if (idx >= 0x2121 && idx <= 0x2C71) {
                        m = 0xD9;
                        n = 0x21;
                } else if (idx >= 0x4A21 && idx <= 0x7D7E) {
                        m = 0xE0;
                        n = 0x4A;
                } else {
                        return EILSEQ;
                }
                l = ((idx >> 8) & 0xFF) - n;
                t = (idx & 0xFF) - 0x21;
                linear = (l * 94) + t;
                l = (linear / 188) + m;
                t = linear % 188;
                t += (t <= 0x4D) ? 0x31 : 0x43;
                *wc = (wchar_t)((l << 8) | t);
                break;
        default:
                return EILSEQ;
        }
        return 0;
}

static __inline int
/*ARGSUSED*/
_citrus_JOHAB_stdenc_get_state_desc_generic(_JOHABEncodingInfo * __restrict ei,
        _JOHABState * __restrict psenc, int * __restrict rstate)
{
        /* ei may be unused */
        _DIAGASSERT(psenc != NULL);
        _DIAGASSERT(rstate != NULL);

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

/* ----------------------------------------------------------------------
 * public interface for ctype
 */

_CITRUS_CTYPE_DECLS(JOHAB);
_CITRUS_CTYPE_DEF_OPS(JOHAB);

#include "citrus_ctype_template.h"


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

_CITRUS_STDENC_DECLS(JOHAB);
_CITRUS_STDENC_DEF_OPS(JOHAB);

#include "citrus_stdenc_template.h"