wcsmbs/mbrtowc.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <gconv.h>
  22 #include <wchar.h>
  23 #include <wcsmbsload.h>
  24
  25 #include <assert.h>
  26
  27 #ifndef EILSEQ
  28 # define EILSEQ EINVAL
  29 #endif
  30
  31 /* This is the private state used if PS is NULL.  */
  32 static mbstate_t state;
  33
  34 size_t
  35 __mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
  36 {
  37   wchar_t buf[1];
  38   struct __gconv_step_data data;
  39   int status;
  40   size_t result;
  41   size_t dummy;
  42   const unsigned char *inbuf;
  43   char *outbuf = (char *) (pwc ?: buf);
  44
  45   /* Tell where we want the result.  */
  46   data.__outbuf = outbuf;
  47   data.__outbufend = outbuf + sizeof (wchar_t);
  48   data.__invocation_counter = 0;
  49   data.__internal_use = 1;
  50   data.__is_last = 1;
  51   data.__statep = ps ?: &state;
  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       data.__outbuf = (char *) buf;
  58       s = "";
  59       n = 1;
  60     }
  61
  62   /* Make sure we use the correct function.  */
  63   update_conversion_ptrs ();
  64
  65   /* Do a normal conversion.  */
  66   inbuf = (const unsigned char *) s;
  67   status = (*__wcsmbs_gconv_fcts.towc->__fct) (__wcsmbs_gconv_fcts.towc,
  68                                                &data, &inbuf, inbuf + n,
  69                                                &dummy, 0);
  70
  71   /* There must not be any problems with the conversion but illegal input
  72      characters.  The output buffer must be large enough, otherwise the
  73      definition of MB_CUR_MAX is not correct.  All the other possible
  74      errors also must not happen.  */
  75   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  76           || status == __GCONV_ILLEGAL_INPUT
  77           || status == __GCONV_INCOMPLETE_INPUT
  78           || status == __GCONV_FULL_OUTPUT);
  79
  80   if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  81       || status == __GCONV_FULL_OUTPUT)
  82     {
  83       if (data.__outbuf != (unsigned char *) outbuf
  84           && *(wchar_t *) outbuf == L'\0')
  85         {
  86           /* The converted character is the NUL character.  */
  87           assert (__mbsinit (data.__statep));
  88           result = 0;
  89         }
  90       else
  91         result = inbuf - (const unsigned char *) s;
  92     }
  93   else
  94     {
  95       result = status == __GCONV_INCOMPLETE_INPUT ? (size_t) -2 : (size_t) -1;
  96       __set_errno (EILSEQ);
  97     }
  98
  99   return result;
 100 }
 101 weak_alias (__mbrtowc, mbrtowc)