/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
 * 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/queue.h>

#include <assert.h>
#include <errno.h>
#include <langinfo.h>
#include <uchar.h>

#include "../iconv/citrus_hash.h"
#include "../iconv/citrus_module.h"
#include "../iconv/citrus_iconv.h"
#include "mblocal.h"

typedef struct {
        bool                    initialized;
        struct _citrus_iconv    iconv;
        union {
                charXX_t        widechar[SRCBUF_LEN];
                char            bytes[sizeof(charXX_t) * SRCBUF_LEN];
        } srcbuf;
        size_t                  srcbuf_len;
} _ConversionState;
_Static_assert(sizeof(_ConversionState) <= sizeof(mbstate_t),
    "Size of _ConversionState must not exceed mbstate_t's size.");

size_t
cXXrtomb_l(char * __restrict s, charXX_t c, mbstate_t * __restrict ps,
    locale_t locale)
{
        _ConversionState *cs;
        struct _citrus_iconv *handle;
        char *src, *dst;
        size_t srcleft, dstleft, invlen;
        int err;

        FIX_LOCALE(locale);
        if (ps == NULL)
                ps = &(XLOCALE_CTYPE(locale)->cXXrtomb);
        cs = (_ConversionState *)ps;
        handle = &cs->iconv;

        /* Reinitialize mbstate_t. */
        if (s == NULL || !cs->initialized) {
                if (_citrus_iconv_open(&handle, UTF_XX_INTERNAL,
                    nl_langinfo_l(CODESET, locale)) != 0) {
                        cs->initialized = false;
                        errno = EINVAL;
                        return (-1);
                }
                cs->srcbuf_len = 0;
                cs->initialized = true;
                if (s == NULL)
                        return (1);
        }

        assert(cs->srcbuf_len < sizeof(cs->srcbuf.widechar) / sizeof(charXX_t));
        cs->srcbuf.widechar[cs->srcbuf_len++] = c;

        /* Perform conversion. */
        src = cs->srcbuf.bytes;
        srcleft = cs->srcbuf_len * sizeof(charXX_t);
        dst = s;
        dstleft = MB_CUR_MAX_L(locale);
        err = _citrus_iconv_convert(handle, &src, &srcleft, &dst, &dstleft,
            _CITRUS_ICONV_F_HIDE_INVALID, &invlen);

        /* Character is part of a surrogate pair. We need more input. */
        if (err == EINVAL)
                return (0);
        cs->srcbuf_len = 0;
        
        /* Illegal sequence. */
        if (dst == s) {
                errno = EILSEQ;
                return ((size_t)-1);
        }
        return (dst - s);
}

size_t
cXXrtomb(char * __restrict s, charXX_t c, mbstate_t * __restrict ps)
{

        return (cXXrtomb_l(s, c, ps, __get_locale()));
}