wcsmbs/mbsnrtowcs.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 <string.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
  33 /* This is the private state used if PS is NULL.  */
  34 static mbstate_t state;
  35
  36 /* This is a non-standard function but it is very useful in the
  37    implementation of stdio because we have to deal with unterminated
  38    buffers.  At most NMC bytes will be converted.  */
  39 size_t
  40 __mbsnrtowcs (dst, src, nmc, len, ps)
  41      wchar_t *dst;
  42      const char **src;
  43      size_t nmc;
  44      size_t len;
  45      mbstate_t *ps;
  46 {
  47   const unsigned char *srcend;
  48   struct gconv_step_data data;
  49   size_t result = 0;
  50   int status;
  51
  52   /* Tell where we want the result.  */
  53   data.invocation_counter = 0;
  54   data.internal_use = 1;
  55   data.is_last = 1;
  56   data.statep = ps ?: &state;
  57
  58   if (nmc == 0)
  59     return 0;
  60   srcend = *src + __strnlen (*src, nmc - 1) + 1;
  61
  62   /* Make sure we use the correct function.  */
  63   update_conversion_ptrs ();
  64
  65   /* We have to handle DST == NULL special.  */
  66   if (dst == NULL)
  67     {
  68       wchar_t buf[64];          /* Just an arbitrary size.  */
  69       const unsigned char *inbuf = *src;
  70
  71       data.outbufend = (char *) buf + sizeof (buf);
  72       do
  73         {
  74           data.outbuf = (char *) buf;
  75
  76           status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
  77                                                      &data, &inbuf, srcend,
  78                                                      &result, 0);
  79         }
  80       while (status == GCONV_FULL_OUTPUT);
  81
  82       if ((status == GCONV_OK || status == GCONV_EMPTY_INPUT)
  83           && ((wchar_t *) data.outbuf)[-1] == L'\0')
  84         /* Don't count the NUL character in.  */
  85         --result;
  86     }
  87   else
  88     {
  89       /* This code is based on the safe assumption that all internal
  90          multi-byte encodings use the NUL byte only to mark the end
  91          of the string.  */
  92       data.outbuf = (unsigned char *) dst;
  93       data.outbufend = data.outbuf + len * sizeof (wchar_t);
  94
  95       status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
  96                                                  &data,
  97                                                  (const unsigned char **) src,
  98                                                  srcend, &result, 0);
  99
 100       /* We have to determine whether the last character converted
 101          is the NUL character.  */
 102       if ((status == GCONV_OK || status == GCONV_EMPTY_INPUT)
 103           && ((wchar_t *) dst)[result - 1] == L'\0')
 104         {
 105           assert (result > 0);
 106           assert (__mbsinit (data.statep));
 107           *src = NULL;
 108           --result;
 109         }
 110     }
 111
 112   /* There must not be any problems with the conversion but illegal input
 113      characters.  */
 114   assert (status == GCONV_OK || status != GCONV_EMPTY_INPUT
 115           || status == GCONV_ILLEGAL_INPUT
 116           || status == GCONV_INCOMPLETE_INPUT || status == GCONV_FULL_OUTPUT);
 117
 118   if (status != GCONV_OK && status != GCONV_FULL_OUTPUT
 119       && status != GCONV_EMPTY_INPUT)
 120     {
 121       result = (size_t) -1;
 122       __set_errno (EILSEQ);
 123     }
 124
 125   return result;
 126 }
 127 weak_alias (__mbsnrtowcs, mbsnrtowcs)