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   struct __gconv_step *towc;
  52
  53   /* Tell where we want the result.  */
  54   data.__invocation_counter = 0;
  55   data.__internal_use = 1;
  56   data.__is_last = 1;
  57   data.__statep = ps ?: &state;
  58
  59   if (nmc == 0)
  60     return 0;
  61   srcend = *src + __strnlen (*src, nmc - 1) + 1;
  62
  63   /* Make sure we use the correct function.  */
  64   update_conversion_ptrs ();
  65
  66   /* Get the structure with the function pointers.  */
  67   towc = __wcsmbs_gconv_fcts.towc;
  68
  69   /* We have to handle DST == NULL special.  */
  70   if (dst == NULL)
  71     {
  72       wchar_t buf[64];          /* Just an arbitrary size.  */
  73       const unsigned char *inbuf = *src;
  74
  75       data.__outbufend = (char *) buf + sizeof (buf);
  76       do
  77         {
  78           data.__outbuf = (char *) buf;
  79
  80           status = (*towc->__fct) (__wcsmbs_gconv_fcts.towc, &data, &inbuf,
  81                                    srcend, &result, 0);
  82         }
  83       while (status == __GCONV_FULL_OUTPUT);
  84
  85       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
  86           && ((wchar_t *) data.__outbuf)[-1] == L'\0')
  87         /* Don't count the NUL character in.  */
  88         --result;
  89     }
  90   else
  91     {
  92       /* This code is based on the safe assumption that all internal
  93          multi-byte encodings use the NUL byte only to mark the end
  94          of the string.  */
  95       data.__outbuf = (unsigned char *) dst;
  96       data.__outbufend = data.__outbuf + len * sizeof (wchar_t);
  97
  98       status = (*towc->__fct) (__wcsmbs_gconv_fcts.towc, &data,
  99                                (const unsigned char **) src, srcend,
 100                                &result, 0);
 101
 102       /* We have to determine whether the last character converted
 103          is the NUL character.  */
 104       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 105           && ((wchar_t *) dst)[result - 1] == L'\0')
 106         {
 107           assert (result > 0);
 108           assert (__mbsinit (data.__statep));
 109           *src = NULL;
 110           --result;
 111         }
 112     }
 113
 114   /* There must not be any problems with the conversion but illegal input
 115      characters.  */
 116   assert (status == __GCONV_OK || status != __GCONV_EMPTY_INPUT
 117           || status == __GCONV_ILLEGAL_INPUT
 118           || status == __GCONV_INCOMPLETE_INPUT
 119           || status == __GCONV_FULL_OUTPUT);
 120
 121   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
 122       && status != __GCONV_EMPTY_INPUT)
 123     {
 124       result = (size_t) -1;
 125       __set_errno (EILSEQ);
 126     }
 127
 128   return result;
 129 }
 130 weak_alias (__mbsnrtowcs, mbsnrtowcs)