wcsmbs/mbsnrtowcs.c

   1 /* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 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   size_t inbytes_in;
  48   struct gconv_step_data data;
  49   size_t result = 0;
  50   int status;
  51
  52   /* Tell where we want the result.  */
  53   data.is_last = 1;
  54   data.statep = ps ?: &state;
  55
  56   if (nmc == 0)
  57     return 0;
  58   inbytes_in = __strnlen (*src, nmc - 1) + 1;
  59
  60   /* Make sure we use the correct function.  */
  61   update_conversion_ptrs ();
  62
  63   /* We have to handle DST == NULL special.  */
  64   if (dst == NULL)
  65     {
  66       wchar_t buf[64];          /* Just an arbitrary size.  */
  67       size_t inbytes = inbytes_in;
  68       const char *inbuf = *src;
  69       size_t written;
  70
  71       data.outbuf = (char *) buf;
  72       data.outbufsize = sizeof (buf);
  73       do
  74         {
  75           inbuf += inbytes_in - inbytes;
  76           inbytes_in = inbytes;
  77           data.outbufavail = 0;
  78           written = 0;
  79
  80           status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
  81                                                      &data, inbuf, &inbytes,
  82                                                      &written, 0);
  83           result += written;
  84         }
  85       while (status == GCONV_FULL_OUTPUT);
  86
  87       if (status == GCONV_OK && ((wchar_t *) dst)[written - 1] == L'\0')
  88         /* Don't count the NUL character in.  */
  89         --result;
  90     }
  91   else
  92     {
  93       /* This code is based on the safe assumption that all internal
  94          multi-byte encodings use the NUL byte only to mark the end
  95          of the string.  */
  96       size_t inbytes = inbytes_in;
  97
  98       data.outbuf = (char *) dst;
  99       data.outbufsize = len * sizeof (wchar_t);
 100       data.outbufavail = 0;
 101
 102       status = (*__wcsmbs_gconv_fcts.towc->fct) (__wcsmbs_gconv_fcts.towc,
 103                                                  &data, *src, &inbytes,
 104                                                  &result, 0);
 105
 106       /* We have to determine whether the last character converted
 107          is the NUL character.  */
 108       if (status == GCONV_OK && ((wchar_t *) dst)[result - 1] == L'\0')
 109         {
 110           assert (result > 0);
 111           assert (mbsinit (data.statep));
 112           *src = NULL;
 113           --result;
 114         }
 115       else
 116         *src += inbytes_in - inbytes;
 117     }
 118
 119   /* There must not be any problems with the conversion but illegal input
 120      characters.  */
 121   assert (status == GCONV_OK || status == GCONV_ILLEGAL_INPUT
 122           || status == GCONV_INCOMPLETE_INPUT || status == GCONV_FULL_OUTPUT);
 123
 124   if (status != GCONV_OK && status != GCONV_FULL_OUTPUT)
 125     {
 126       result = (size_t) -1;
 127       __set_errno (EILSEQ);
 128     }
 129
 130   return result;
 131 }
 132 weak_alias (__mbsnrtowcs, mbsnrtowcs)