glibc/wcsmbs/btowc.c

/* Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <gconv.h>
#include <stdio.h>
#include <string.h>
#include <wchar.h>
#include <wcsmbsload.h>
#include <limits.h>


wint_t
__btowc (c)
     int c;
{
  wchar_t result;
  struct gconv_step_data data;
  unsigned char inbuf[1];
  const unsigned char *inptr = inbuf;
  size_t dummy;
  int status;

  /* If the parameter does not fit into one byte or it is the EOF value
     we can give the answer now.  */
  if (c < SCHAR_MIN || c > UCHAR_MAX || c == EOF)
    return WEOF;

  /* Tell where we want the result.  */
  data.outbuf = (unsigned char *) &result;
  data.outbufend = data.outbuf + sizeof (wchar_t);
  data.invocation_counter = 0;
  data.internal_use = 1;
  data.is_last = 1;
  data.statep = &data.__state;

  /* Make sure we start in the initial state.  */
  memset (&data.__state, '\0', sizeof (mbstate_t));

  /* Make sure we use the correct function.  */
  update_conversion_ptrs ();

  /* Create the input string.  */
  inbuf[0] = c;

  status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc, &data,
					     &inptr, inptr + 1, &dummy, 0);
  /* The conversion failed.  */
  if (status != GCONV_OK && status != GCONV_FULL_OUTPUT
      && status != GCONV_EMPTY_INPUT)
    result = WEOF;

  return result;
}
weak_alias (__btowc, btowc)