/*-
 * As noted in the source, some portions of this implementation are copied from
 * FreeBSD libc.  These are covered by the following copyright:
 *
 * Copyright (c) 2002-2004 Tim J. Robbins.
 *
 * 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.
 */

size_t
mbsnrtowcs_l(wchar_t * __restrict dst, const char ** __restrict src,
    size_t nms, size_t len, mbstate_t * __restrict ps, locale_t loc)
{
  const char *s;
  size_t nchr;
  wchar_t wc;
  size_t nb;
  FIX_LOCALE(loc);

  s = *src;
  nchr = 0;

  if (dst == NULL) {
    for (;;) {
      if ((nb = mbrtowc_l(&wc, s, nms, ps, loc)) == (size_t)-1)
        /* Invalid sequence - mbrtowc() sets errno. */
        return ((size_t)-1);
      else if (nb == 0 || nb == (size_t)-2)
        return (nchr);
      s += nb;
      nms -= nb;
      nchr++;
    }
    /*NOTREACHED*/
  }

  while (len-- > 0) {
    if ((nb = mbrtowc_l(dst, s, nms, ps, loc)) == (size_t)-1) {
      *src = s;
      return ((size_t)-1);
    } else if (nb == (size_t)-2) {
      *src = s + nms;
      return (nchr);
    } else if (nb == 0) {
      *src = NULL;
      return (nchr);
    }
    s += nb;
    nms -= nb;
    nchr++;
    dst++;
  }
  *src = s;
  return (nchr);
}