/* Copyright (C) 1991-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdlib.h>

#include <string.h>

#include <wchar.h>

#include <gconv.h>

#include <wcsmbs/wcsmbsload.h>

/* Internal state.  */

static mbstate_t state;

/* Return the length of the multibyte character (if there is one)

   at S which is no longer than N characters.

   The ISO C standard says that the `mblen' function must not change

   the state of the `mbtowc' function.  */

int

mblen (const char *s, size_t n)

{

  int result;

  /* If S is NULL the function has to return null or not null

     depending on the encoding having a state depending encoding or

     not.  */

  if (s == NULL)

    {

      const struct gconv_fcts *fcts;

      /* Get the conversion functions.  */

      fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));

      /* Reset the state.  */

      memset (&state, '\0', sizeof state);

      result = fcts->towc->__stateful;

    }

  else if (*s == '\0')

    /* According to the ISO C 89 standard this is the expected behaviour.  */

    result = 0;

  else

    {

      memset (&state, '\0', sizeof state);

      result = __mbrtowc (NULL, s, n, &state);

      /* The `mbrtowc' functions tell us more than we need.  Fold the -1

	 and -2 result into -1.  */

      if (result < 0)

	result = -1;

    }

  return result;

}