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

/*-
 * 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 "dcmtk/config/osconfig.h"
#include "citrus_utf8.h"

#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.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
 */

static uint8_t _UTF8_count_array[256] = {
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 00 - 0F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 10 - 1F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 20 - 2F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 30 - 3F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 40 - 4F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 50 - 5F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 60 - 6F */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 70 - 7F */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 80 - 8F */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 90 - 9F */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A0 - AF */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* B0 - BF */
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* C0 - CF */
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* D0 - DF */
    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, /* E0 - EF */
    4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 0, 0  /* F0 - FF */
};

static uint8_t const *_UTF8_count = _UTF8_count_array;

static const uint32_t _UTF8_range[] = {
    0,  /*dummy*/
    0x00000000, 0x00000080, 0x00000800, 0x00010000,
    0x00200000, 0x04000000, 0x80000000,
};

typedef struct {
    int  chlen;
    char     ch[6];
} _UTF8State;

typedef void *_UTF8EncodingInfo;

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

#define _FUNCNAME(m)            _citrus_UTF8_##m
#define _ENCODING_INFO          _UTF8EncodingInfo
#define _ENCODING_STATE         _UTF8State
#define _ENCODING_MB_CUR_MAX(_ei_)  6
#define _ENCODING_IS_STATE_DEPENDENT    0
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)    0

static size_t
_UTF8_findlen(_citrus_wc_t v)
{
    size_t i;
    uint32_t c;

    c = (uint32_t)v;    /*XXX*/
    for (i = 1; i < sizeof(_UTF8_range) / sizeof(_UTF8_range[0]) - 1; i++)
        if (c >= _UTF8_range[i] && c < _UTF8_range[i + 1])
            return (i);

    return ((size_t) -1);    /*out of range*/
}

static __inline bool
_UTF8_surrogate(_citrus_wc_t wc)
{

    return (wc >= 0xd800 && wc <= 0xdfff);
}

static __inline void
/*ARGSUSED*/
_citrus_UTF8_init_state(_UTF8EncodingInfo *ei , _UTF8State *s)
{
    (void) ei;
    s->chlen = 0;
}

static int
_citrus_UTF8_mbrtowc_priv(_UTF8EncodingInfo *ei, _citrus_wc_t *pwc, char **s,
    size_t n, _UTF8State *psenc, size_t *nresult)
{
    char *s0;
    _citrus_wc_t wchar;
    int i;
    uint8_t c;

    s0 = *s;

    if (s0 == NULL) {
        _citrus_UTF8_init_state(ei, psenc);
        *nresult = 0; /* state independent */
        return (0);
    }

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

    c = _UTF8_count[psenc->ch[0] & 0xff];
    if (c < 1 || c < psenc->chlen)
        goto ilseq;

    if (c == 1)
        wchar = psenc->ch[0] & 0xff;
    else {
        while (psenc->chlen < c) {
            if (n-- < 1)
                goto restart;
            psenc->ch[psenc->chlen++] = *s0++;
        }
        wchar = psenc->ch[0] & (0x7f >> c);
        for (i = 1; i < c; i++) {
            if ((psenc->ch[i] & 0xc0) != 0x80)
                goto ilseq;
            wchar <<= 6;
            wchar |= (psenc->ch[i] & 0x3f);
        }
        if (_UTF8_surrogate(wchar) || _UTF8_findlen(wchar) != c)
            goto ilseq;
    }
    if (pwc != NULL)
        *pwc = wchar;
    *nresult = (wchar == 0) ? 0 : s0 - *s;
    *s = s0;
    psenc->chlen = 0;

    return (0);

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

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

static int
_citrus_UTF8_wcrtomb_priv(_UTF8EncodingInfo *ei , char *s, size_t n,
    _citrus_wc_t wc, _UTF8State *psenc , size_t *nresult)
{
    _citrus_wc_t c;
    size_t cnt, i;
    int ret;

    (void) ei;
    (void) psenc;
    if (_UTF8_surrogate(wc)) {
        ret = EILSEQ;
        goto err;
    }
    cnt = _UTF8_findlen(wc);
    if (cnt <= 0 || cnt > 6) {
        /* invalid UCS4 value */
        ret = EILSEQ;
        goto err;
    }
    if (n < cnt) {
        /* bound check failure */
        ret = E2BIG;
        goto err;
    }

    c = wc;
    if (s) {
        for (i = cnt - 1; i > 0; i--) {
            s[i] = 0x80 | (c & 0x3f);
            c >>= 6;
        }
        s[0] = (char) c;
        if (cnt == 1)
            s[0] &= 0x7f;
        else {
            s[0] &= (0x7f >> cnt);
            s[0] |= ((0xff00 >> cnt) & 0xff);
        }
    }

    *nresult = (size_t)cnt;
    return (0);

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

static __inline int
/*ARGSUSED*/
_citrus_UTF8_stdenc_wctocs(_UTF8EncodingInfo * ei ,
    _citrus_csid_t * csid, _citrus_index_t * idx,
    _citrus_wc_t wc)
{
    (void) ei;

    *csid = 0;
    *idx = (_citrus_index_t)wc;

    return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_UTF8_stdenc_cstowc(_UTF8EncodingInfo * ei ,
    _citrus_wc_t * wc, _citrus_csid_t csid, _citrus_index_t idx)
{
    (void) ei;

    if (csid != 0)
        return (EILSEQ);

    *wc = (_citrus_wc_t)idx;

    return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_UTF8_stdenc_get_state_desc_generic(_UTF8EncodingInfo * ei ,
    _UTF8State * psenc, int * rstate)
{
    (void) ei;
    *rstate = (psenc->chlen == 0) ? _CITRUS_STDENC_SDGEN_INITIAL :
        _CITRUS_STDENC_SDGEN_INCOMPLETE_CHAR;
    return (0);
}

static int
/*ARGSUSED*/
_citrus_UTF8_encoding_module_init(_UTF8EncodingInfo * ei ,
    const void * var , size_t lenvar )
{
    (void) ei;
    (void) var;
    (void) lenvar;

    return (0);
}

static void
/*ARGSUSED*/
_citrus_UTF8_encoding_module_uninit(_UTF8EncodingInfo *ei )
{
    (void) ei;
}

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

_CITRUS_STDENC_DECLS(UTF8);
_CITRUS_STDENC_DEF_OPS(UTF8);

#include "citrus_stdenc_template.h"
