wcsmbs/btowc.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.org>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <dlfcn.h>
  21 #include <gconv.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <wchar.h>
  25 #include <wcsmbsload.h>
  26 #include <limits.h>
  27
  28
  29 wint_t
  30 __btowc (c)
  31      int c;
  32 {
  33   wchar_t result;
  34   struct __gconv_step_data data;
  35   unsigned char inbuf[1];
  36   const unsigned char *inptr = inbuf;
  37   size_t dummy;
  38   int status;
  39
  40   /* If the parameter does not fit into one byte or it is the EOF value
  41      we can give the answer now.  */
  42   if (c < SCHAR_MIN || c > UCHAR_MAX || c == EOF)
  43     return WEOF;
  44
  45   /* Tell where we want the result.  */
  46   data.__outbuf = (unsigned char *) &result;
  47   data.__outbufend = data.__outbuf + sizeof (wchar_t);
  48   data.__invocation_counter = 0;
  49   data.__internal_use = 1;
  50   data.__flags = __GCONV_IS_LAST;
  51   data.__statep = &data.__state;
  52   data.__trans = NULL;
  53
  54   /* Make sure we start in the initial state.  */
  55   memset (&data.__state, '\0', sizeof (mbstate_t));
  56
  57   /* Make sure we use the correct function.  */
  58   update_conversion_ptrs ();
  59
  60   /* Create the input string.  */
  61   inbuf[0] = c;
  62
  63   status = DL_CALL_FCT (__wcsmbs_gconv_fcts.towc->__fct,
  64                         (__wcsmbs_gconv_fcts.towc, &data, &inptr, inptr + 1,
  65                          NULL, &dummy, 0, 1));
  66   /* The conversion failed.  */
  67   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
  68       && status != __GCONV_EMPTY_INPUT)
  69     result = WEOF;
  70
  71   return result;
  72 }
  73 weak_alias (__btowc, btowc)