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 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   mbstate_t temp_state;
  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.__is_last = 1;
  50   data.__statep = ps ?: &state;
  51
  52   /* A first special case is if S is NULL.  This means put PS in the
  53      initial state.  */
  54   if (s == NULL)
  55     {
  56       outbuf = (char *) buf;
  57       s = "";
  58       n = 1;
  59       temp_state = *data.__statep;
  60       data.__statep = &temp_state;
  61     }
  62
  63   /* Tell where we want the result.  */
  64   data.__outbuf = outbuf;
  65   data.__outbufend = outbuf + sizeof (wchar_t);
  66
  67   /* Make sure we use the correct function.  */
  68   update_conversion_ptrs ();
  69
  70   /* Do a normal conversion.  */
  71   inbuf = (const unsigned char *) s;
  72   status = (*__wcsmbs_gconv_fcts.towc->__fct) (__wcsmbs_gconv_fcts.towc,
  73                                                &data, &inbuf, inbuf + n,
  74                                                &dummy, 0, 1);
  75
  76   /* There must not be any problems with the conversion but illegal input
  77      characters.  The output buffer must be large enough, otherwise the
  78      definition of MB_CUR_MAX is not correct.  All the other possible
  79      errors also must not happen.  */
  80   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  81           || status == __GCONV_ILLEGAL_INPUT
  82           || status == __GCONV_INCOMPLETE_INPUT
  83           || status == __GCONV_FULL_OUTPUT);
  84
  85   if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  86       || status == __GCONV_FULL_OUTPUT)
  87     {
  88       if (data.__outbuf != (unsigned char *) outbuf
  89           && *(wchar_t *) outbuf == L'\0')
  90         {
  91           /* The converted character is the NUL character.  */
  92           assert (__mbsinit (data.__statep));
  93           result = 0;
  94         }
  95       else
  96         result = inbuf - (const unsigned char *) s;
  97     }
  98   else if (status == __GCONV_INCOMPLETE_INPUT)
  99     result = (size_t) -2;
 100   else
 101     {
 102       result = (size_t) -1;
 103       __set_errno (EILSEQ);
 104     }
 105
 106   return result;
 107 }
 108 weak_alias (__mbrtowc, mbrtowc)