/*      $NetBSD: citrus_utf8.c,v 1.22 2026/07/04 13:21:05 riastradh 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.
 */

/*-
 * 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: citrus_utf8.c,v 1.22 2026/07/04 13:21:05 riastradh Exp $");
#endif /* LIBC_SCCS and not lint */

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

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_module.h"
#include "citrus_ctype.h"
#include "citrus_stdenc.h"
#include "citrus_utf8.h"


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

static int _UTF8_count_array[256];
static int const *_UTF8_count = NULL;

static struct __UTF_B2 {
        unsigned char low;
        unsigned char high;
} _UTF8_Byte2_array[256];
static const struct __UTF_B2 *_UTF8_Byte2;

static const u_int32_t _UTF8_range[] = {
        0,      /*dummy*/
        0x00000000, 0x00000080, 0x00000800, 0x00010000, 
        0x00110000,
};

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

typedef struct {
} _UTF8EncodingInfo;

typedef struct {
        _UTF8EncodingInfo       ei;
        struct {
                /* for future multi-locale facility */
                _UTF8State      s_mblen;
                _UTF8State      s_mbrlen;
                _UTF8State      s_mbrtowc;
                _UTF8State      s_mbtowc;
                _UTF8State      s_mbsrtowcs;
                _UTF8State      s_mbsnrtowcs;
                _UTF8State      s_wcrtomb;
                _UTF8State      s_wcsrtombs;
                _UTF8State      s_wcsnrtombs;
                _UTF8State      s_wctomb;
        } states;
} _UTF8CTypeInfo;

#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 _CTYPE_INFO                     _UTF8CTypeInfo
#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 __inline void
_UTF8_init_count(void)
{
        int i;

        if (!_UTF8_count) {
                memset(_UTF8_count_array, 0, sizeof(_UTF8_count_array));
                memset(_UTF8_Byte2_array, 0, sizeof(_UTF8_Byte2_array));

                /*
                 * Values from Unicode standard rev 17, Table 3.7
                 */
                for (i = 0; i <= 0x7f; i++)
                        _UTF8_count_array[i] = 1;
                for (i = 0xc2; i <= 0xdf; i++) {
                        _UTF8_count_array[i] = 2;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xe0; i <= 0xe0; i++) {
                        _UTF8_count_array[i] = 3;
                        _UTF8_Byte2_array[i].low = 0xA0;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xe1; i <= 0xec; i++) {
                        _UTF8_count_array[i] = 3;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xed; i <= 0xed; i++) {
                        _UTF8_count_array[i] = 3;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0x9F;
                }
                for (i = 0xee; i <= 0xef; i++) {
                        _UTF8_count_array[i] = 3;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xf0; i <= 0xf0; i++) {
                        _UTF8_count_array[i] = 4;
                        _UTF8_Byte2_array[i].low = 0x90;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xf1; i <= 0xf3; i++) {
                        _UTF8_count_array[i] = 4;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0xBF;
                }
                for (i = 0xf4; i <= 0xf4; i++) {
                        _UTF8_count_array[i] = 4;
                        _UTF8_Byte2_array[i].low = 0x80;
                        _UTF8_Byte2_array[i].high = 0x8F;
                }
                _UTF8_count = _UTF8_count_array;
                _UTF8_Byte2 = _UTF8_Byte2_array;
        }
}

static int
_UTF8_findlen(wchar_t v)
{
        int i;
        u_int32_t c;

        c = (u_int32_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 int
_UTF8_surrogate(wchar_t wc)
{
        return wc >= 0xd800 && wc <= 0xdfff;
}

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

static __inline void
/*ARGSUSED*/
_citrus_UTF8_pack_state(_UTF8EncodingInfo *ei, void *pspriv,
                        const _UTF8State *s)
{
        memcpy(pspriv, (const void *)s, sizeof(*s));
}

static __inline void
/*ARGSUSED*/
_citrus_UTF8_unpack_state(_UTF8EncodingInfo *ei, _UTF8State *s,
                          const void *pspriv)
{
        memcpy((void *)s, pspriv, sizeof(*s));
}

static int
_citrus_UTF8_mbrtowc_priv(_UTF8EncodingInfo *ei, wchar_t *pwc, const char **s,
                          size_t n, _UTF8State *psenc, size_t *nresult)
{
        wchar_t wchar;
        const char *s0;
        int c;
        int i;
        unsigned char ch;

        _DIAGASSERT(nresult != 0);
        _DIAGASSERT(s != NULL);
        _DIAGASSERT(psenc != NULL);

        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[ch = (unsigned char)psenc->ch[0]];
        if (c < 1 || c < psenc->chlen)
                goto ilseq;

        if (c == 1)
                wchar = ch;
        else {
                if (psenc->chlen == 1 && n >= 1 &&
                    (_UTF8_Byte2[ch].low > (unsigned char)*s0 ||
                    _UTF8_Byte2[ch].high < (unsigned char)*s0) )
                        goto ilseq;

                while (psenc->chlen < c) {
                        if (n-- < 1)
                                goto restart;
                        if ((*s0 & 0xc0) != 0x80)
                                goto ilseq;
                        psenc->ch[psenc->chlen++] = *s0++;
                }
                wchar = psenc->ch[0] & (0x7f >> c);
                for (i = 1; i < c; i++) {
                        wchar <<= 6;
                        wchar |= (psenc->ch[i] & 0x3f);
                }
                _DIAGASSERT(!_UTF8_surrogate(wchar));
                _DIAGASSERT(_UTF8_findlen(wchar) == c);
        }
        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, wchar_t wc,
                          _UTF8State *psenc, size_t *nresult)
{
        int cnt, i, ret;
        wchar_t c;

        _DIAGASSERT(nresult != 0);
        _DIAGASSERT(s != NULL);

        if (_UTF8_surrogate(wc)) {
                ret = EILSEQ;
                goto err;
        }
        cnt = _UTF8_findlen(wc);
        if (cnt <= 0 || cnt > 4) {
                /* 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,
                           _csid_t * __restrict csid,
                           _index_t * __restrict idx,
                           wchar_t wc)
{

        _DIAGASSERT(csid != NULL && idx != NULL);

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

        return (0);
}

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

        _DIAGASSERT(wc != NULL);

        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,
                                           _UTF8State * __restrict psenc,
                                           int * __restrict rstate)
{

        if (psenc->chlen == 0)
                *rstate = _STDENC_SDGEN_INITIAL;
        else
                *rstate = _STDENC_SDGEN_INCOMPLETE_CHAR;

        return 0;
}

static int
/*ARGSUSED*/
_citrus_UTF8_encoding_module_init(_UTF8EncodingInfo * __restrict ei,
                                  const void * __restrict var, size_t lenvar)
{
        _UTF8_init_count();

        return 0;
}

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


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

_CITRUS_CTYPE_DECLS(UTF8);
_CITRUS_CTYPE_DEF_OPS(UTF8);

#include "citrus_ctype_template.h"

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

_CITRUS_STDENC_DECLS(UTF8);
_CITRUS_STDENC_DEF_OPS(UTF8);

#include "citrus_stdenc_template.h"