/*      $OpenBSD: vswprintf.c,v 1.8 2025/08/08 15:58:53 yasuoka Exp $   */
/*      $NetBSD: vswprintf.c,v 1.1 2005/05/14 23:51:02 christos Exp $   */

/*
 * Copyright (c) 1997 Todd C. Miller <millert@openbsd.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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 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 <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <stdarg.h>
#include "local.h"

int
vswprintf(wchar_t * __restrict s, size_t n, const wchar_t * __restrict fmt,
    __va_list ap)
{
        mbstate_t mbs;
        FILE f = FILEINIT(__SWR | __SSTR | __SALC);
        char *mbp;
        int ret, sverrno;
        size_t nwc;

        if (n == 0) {
                errno = EINVAL;
                return (-1);
        }

        f._bf._base = f._p = malloc(128);
        if (f._bf._base == NULL) {
                errno = ENOMEM;
                return (-1);
        }
        f._bf._size = f._w = 127;               /* Leave room for the NUL */
        ret = __vfwprintf(&f, fmt, ap);
        if (ret < 0) {
                sverrno = errno;
                free(f._bf._base);
                errno = sverrno;
                return (-1);
        }
        if (ret == 0) {
                s[0] = L'\0';
                free(f._bf._base);
                return (0);
        }
        *f._p = '\0';
        mbp = (char *)f._bf._base;
        /*
         * XXX Undo the conversion from wide characters to multibyte that
         * fputwc() did in __vfwprintf().
         */
        bzero(&mbs, sizeof(mbs));
        nwc = mbsrtowcs(s, (const char **)&mbp, n, &mbs);
        free(f._bf._base);
        if (nwc == (size_t)-1) {
                errno = EILSEQ;
                return (-1);
        }
        if (nwc == n) {
                s[n - 1] = L'\0';
                errno = EOVERFLOW;
                return (-1);
        }

        return (ret);
}
DEF_STRONG(vswprintf);