wcsmbs/mbrtowc.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 <errno.h>
  22 #include <gconv.h>
  23 #include <wchar.h>
  24 #include <wcsmbsload.h>
  25
  26 #include <assert.h>
  27
  28 #ifndef EILSEQ
  29 # define EILSEQ EINVAL
  30 #endif
  31
  32 /* This is the private state used if PS is NULL.  */
  33 static mbstate_t state;
  34
  35 size_t
  36 __mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
  37 {
  38   wchar_t buf[1];
  39   struct __gconv_step_data data;
  40   int status;
  41   size_t result;
  42   size_t dummy;
  43   const unsigned char *inbuf;
  44   char *outbuf = (char *) (pwc ?: buf);
  45
  46   /* Set information for this step.  */
  47   data.__invocation_counter = 0;
  48   data.__internal_use = 1;
  49   data.__flags = __GCONV_IS_LAST;
  50   data.__statep = ps ?: &state;
  51   data.__trans = NULL;
  52
  53   /* A first special case is if S is NULL.  This means put PS in the
  54      initial state.  */
  55   if (s == NULL)
  56     {
  57       outbuf = (char *) buf;
  58       s = "";
  59       n = 1;
  60     }
  61
  62   /* Tell where we want the result.  */
  63   data.__outbuf = outbuf;
  64   data.__outbufend = outbuf + sizeof (wchar_t);
  65
  66   /* Make sure we use the correct function.  */
  67   update_conversion_ptrs ();
  68
  69   /* Do a normal conversion.  */
  70   inbuf = (const unsigned char *) s;
  71   status = DL_CALL_FCT (__wcsmbs_gconv_fcts.towc->__fct,
  72                         (__wcsmbs_gconv_fcts.towc, &data, &inbuf, inbuf + n,
  73                          NULL, &dummy, 0, 1));
  74
  75   /* There must not be any problems with the conversion but illegal input
  76      characters.  The output buffer must be large enough, otherwise the
  77      definition of MB_CUR_MAX is not correct.  All the other possible
  78      errors also must not happen.  */
  79   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  80           || status == __GCONV_ILLEGAL_INPUT
  81           || status == __GCONV_INCOMPLETE_INPUT
  82           || status == __GCONV_FULL_OUTPUT);
  83
  84   if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  85       || status == __GCONV_FULL_OUTPUT)
  86     {
  87       if (data.__outbuf != (unsigned char *) outbuf
  88           && *(wchar_t *) outbuf == L'\0')
  89         {
  90           /* The converted character is the NUL character.  */
  91           assert (__mbsinit (data.__statep));
  92           result = 0;
  93         }
  94       else
  95         result = inbuf - (const unsigned char *) s;
  96     }
  97   else if (status == __GCONV_INCOMPLETE_INPUT)
  98     result = (size_t) -2;
  99   else
 100     {
 101       result = (size_t) -1;
 102       __set_errno (EILSEQ);
 103     }
 104
 105   return result;
 106 }
 107 weak_alias (__mbrtowc, mbrtowc)