/*      $NetBSD: citrus_utf8.c,v 1.17 2008/06/14 16:01:08 tnozaki Exp $ */

/*-
 * 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.
 */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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 <sys/types.h>

#include <assert.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_namespace.h"
#include "citrus_types.h"
#include "citrus_module.h"
#include "citrus_stdenc.h"
#include "citrus_utf8.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(wchar_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 (-1);    /*out of range*/
}

static __inline bool
_UTF8_surrogate(wchar_t wc)
{

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

static __inline void
/*ARGSUSED*/
_citrus_UTF8_init_state(_UTF8EncodingInfo *ei __unused, _UTF8State *s)
{

        s->chlen = 0;
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_UTF8_pack_state(_UTF8EncodingInfo *ei __unused, void *pspriv,
    const _UTF8State *s)
{

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

static __inline void
/*ARGSUSED*/
_citrus_UTF8_unpack_state(_UTF8EncodingInfo *ei __unused, _UTF8State *s,
    const void *pspriv)
{

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

static int
_citrus_UTF8_mbrtowc_priv(_UTF8EncodingInfo *ei, wchar_t *pwc, char **s,
    size_t n, _UTF8State *psenc, size_t *nresult)
{
        char *s0;
        wchar_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 __unused, char *s, size_t n,
    wchar_t wc, _UTF8State *psenc __unused, size_t *nresult)
{
        wchar_t c;
        size_t cnt;
        int i, ret;

        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] = 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 * __restrict ei __unused,
    _csid_t * __restrict csid, _index_t * __restrict idx,
    wchar_t wc)
{

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

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_UTF8_stdenc_cstowc(_UTF8EncodingInfo * __restrict ei __unused,
    wchar_t * __restrict wc, _csid_t csid, _index_t idx)
{

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

        *wc = (wchar_t)idx;

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_UTF8_stdenc_get_state_desc_generic(_UTF8EncodingInfo * __restrict ei __unused,
    _UTF8State * __restrict psenc, int * __restrict rstate)
{

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

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

        return (0);
}

static void
/*ARGSUSED*/
_citrus_UTF8_encoding_module_uninit(_UTF8EncodingInfo *ei __unused)
{

}

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

_CITRUS_STDENC_DECLS(UTF8);
_CITRUS_STDENC_DEF_OPS(UTF8);

#include "citrus_stdenc_template.h"