wcsmbs/btowc.c

   1 /* Copyright (C) 1996-2015 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  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 #include <sysdep.h>
  29
  30
  31 wint_t
  32 __btowc (c)
  33      int c;
  34 {
  35   const struct gconv_fcts *fcts;
  36
  37   /* If the parameter does not fit into one byte or it is the EOF value
  38      we can give the answer now.  */
  39   if (c < SCHAR_MIN || c > UCHAR_MAX || c == EOF)
  40     return WEOF;
  41
  42   /* We know that only ASCII compatible encodings are used for the
  43      locale and that the wide character encoding is ISO 10646.  */
  44   if (isascii (c))
  45     return (wint_t) c;
  46
  47   /* Get the conversion functions.  */
  48   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  49   __gconv_btowc_fct btowc_fct = fcts->towc->__btowc_fct;
  50
  51   if (__builtin_expect (fcts->towc_nsteps == 1, 1)
  52       && __builtin_expect (btowc_fct != NULL, 1))
  53     {
  54       /* Use the shortcut function.  */
  55 #ifdef PTR_DEMANGLE
  56       if (fcts->towc->__shlib_handle != NULL)
  57         PTR_DEMANGLE (btowc_fct);
  58 #endif
  59       return DL_CALL_FCT (btowc_fct, (fcts->towc, (unsigned char) c));
  60     }
  61   else
  62     {
  63       /* Fall back to the slow but generic method.  */
  64       wchar_t result;
  65       struct __gconv_step_data data;
  66       unsigned char inbuf[1];
  67       const unsigned char *inptr = inbuf;
  68       size_t dummy;
  69       int status;
  70
  71       /* Tell where we want the result.  */
  72       data.__outbuf = (unsigned char *) &result;
  73       data.__outbufend = data.__outbuf + sizeof (wchar_t);
  74       data.__invocation_counter = 0;
  75       data.__internal_use = 1;
  76       data.__flags = __GCONV_IS_LAST;
  77       data.__statep = &data.__state;
  78
  79       /* Make sure we start in the initial state.  */
  80       memset (&data.__state, '\0', sizeof (mbstate_t));
  81
  82       /* Create the input string.  */
  83       inbuf[0] = c;
  84
  85       __gconv_fct fct = fcts->towc->__fct;
  86 #ifdef PTR_DEMANGLE
  87       if (fcts->towc->__shlib_handle != NULL)
  88         PTR_DEMANGLE (fct);
  89 #endif
  90       status = DL_CALL_FCT (fct, (fcts->towc, &data, &inptr, inptr + 1,
  91                                   NULL, &dummy, 0, 1));
  92
  93       if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
  94           && status != __GCONV_EMPTY_INPUT)
  95         /* The conversion failed.  */
  96         result = WEOF;
  97
  98       return result;
  99     }
 100 }
 101 weak_alias (__btowc, btowc)