/* Copyright (C) 1996-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@gnu.org>, 1996.

   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 <assert.h>

#include <dlfcn.h>

#include <errno.h>

#include <gconv.h>

#include <wchar.h>

#include <wcsmbsload.h>

#include <sysdep.h>

#ifndef EILSEQ

# define EILSEQ EINVAL

#endif

/* This is the private state used if PS is NULL.  */

static mbstate_t state;

size_t

__mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)

{

  wchar_t buf[1];

  struct __gconv_step_data data;

  int status;

  size_t result;

  size_t dummy;

  const unsigned char *inbuf, *endbuf;

  unsigned char *outbuf = (unsigned char *) (pwc ?: buf);

  const struct gconv_fcts *fcts;

  /* Set information for this step.  */

  data.__invocation_counter = 0;

  data.__internal_use = 1;

  data.__flags = __GCONV_IS_LAST;

  data.__statep = ps ?: &stat;;

  /* A first special case is if S is NULL.  This means put PS in the

     initial state.  */

  if (s == NULL)

    {

      outbuf = (unsigned char *) buf;

      s = "";

      n = 1;

    }

  if (n == 0)

    return (size_t) -2;

  /* Tell where we want the result.  */

  data.__outbuf = outbuf;

  data.__outbufend = outbuf + sizeof (wchar_t);

  /* Get the conversion functions.  */

  fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));

  /* Do a normal conversion.  */

  inbuf = (const unsigned char *) s;

  endbuf = inbuf + n;

  if (__glibc_unlikely (endbuf < inbuf))

    {

      endbuf = (const unsigned char *) ~(uintptr_t) 0;

      if (endbuf == inbuf)

	goto ilseq;

    }

  __gconv_fct fct = fcts->towc->__fct;

#ifdef PTR_DEMANGLE

  if (fcts->towc->__shlib_handle != NULL)

    PTR_DEMANGLE (fct);

#endif

  status = DL_CALL_FCT (fct, (fcts->towc, &data, &inbuf, endbuf,

			      NULL, &dummy, 0, 1));

  /* There must not be any problems with the conversion but illegal input

     characters.  The output buffer must be large enough, otherwise the

     definition of MB_CUR_MAX is not correct.  All the other possible

     errors also must not happen.  */

  assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT

	  || status == __GCONV_ILLEGAL_INPUT

	  || status == __GCONV_INCOMPLETE_INPUT

	  || status == __GCONV_FULL_OUTPUT);

  if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT

      || status == __GCONV_FULL_OUTPUT)

    {

      if (data.__outbuf != (unsigned char *) outbuf

	  && *(wchar_t *) outbuf == L'\0')

	{

	  /* The converted character is the NUL character.  */

	  assert (__mbsinit (data.__statep));

	  result = 0;

	}

      else

	result = inbuf - (const unsigned char *) s;

    }

  else if (status == __GCONV_INCOMPLETE_INPUT)

    result = (size_t) -2;

  else

    {

    ilseq:

      result = (size_t) -1;

      __set_errno (EILSEQ);

    }

  return result;

}

libc_hidden_def (__mbrtowc)

weak_alias (__mbrtowc, mbrtowc)

libc_hidden_weak (mbrtowc)

/* There should be no difference between the UTF-32 handling required

   by mbrtoc32 and the wchar_t handling which has long since been

   implemented in mbrtowc.  */

weak_alias (__mbrtowc, mbrtoc32)