wcsmbs/mbsnrtowcs.c

   1 /* Copyright (C) 1996-2017 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <dlfcn.h>
  21 #include <errno.h>
  22 #include <gconv.h>
  23 #include <string.h>
  24 #include <wchar.h>
  25 #include <wcsmbsload.h>
  26
  27 #include <sysdep.h>
  28
  29 #ifndef EILSEQ
  30 # define EILSEQ EINVAL
  31 #endif
  32
  33
  34 /* This is the private state used if PS is NULL.  */
  35 static mbstate_t state;
  36
  37 /* This is a non-standard function but it is very useful in the
  38    implementation of stdio because we have to deal with unterminated
  39    buffers.  At most NMC bytes will be converted.  */
  40 size_t
  41 __mbsnrtowcs (wchar_t *dst, const char **src, size_t nmc, size_t len,
  42               mbstate_t *ps)
  43 {
  44   const unsigned char *srcend;
  45   struct __gconv_step_data data;
  46   size_t result;
  47   int status;
  48   struct __gconv_step *towc;
  49   size_t dummy;
  50   const struct gconv_fcts *fcts;
  51
  52   /* Tell where we want the result.  */
  53   data.__invocation_counter = 0;
  54   data.__internal_use = 1;
  55   data.__flags = __GCONV_IS_LAST;
  56   data.__statep = ps ?: &state;
  57
  58   if (nmc == 0)
  59     return 0;
  60   srcend = (const unsigned char *) *src + __strnlen (*src, nmc - 1) + 1;
  61
  62   /* Get the conversion functions.  */
  63   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  64
  65   /* Get the structure with the function pointers.  */
  66   towc = fcts->towc;
  67   __gconv_fct fct = towc->__fct;
  68 #ifdef PTR_DEMANGLE
  69   if (towc->__shlib_handle != NULL)
  70     PTR_DEMANGLE (fct);
  71 #endif
  72
  73   /* We have to handle DST == NULL special.  */
  74   if (dst == NULL)
  75     {
  76       mbstate_t temp_state;
  77       wchar_t buf[64];          /* Just an arbitrary size.  */
  78       const unsigned char *inbuf = (const unsigned char *) *src;
  79
  80       temp_state = *data.__statep;
  81       data.__statep = &temp_state;
  82
  83       result = 0;
  84       data.__outbufend = (unsigned char *) buf + sizeof (buf);
  85       do
  86         {
  87           data.__outbuf = (unsigned char *) buf;
  88
  89           status = DL_CALL_FCT (fct, (towc, &data, &inbuf, srcend, NULL,
  90                                       &dummy, 0, 1));
  91
  92           result += (wchar_t *) data.__outbuf - buf;
  93         }
  94       while (status == __GCONV_FULL_OUTPUT);
  95
  96       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
  97           && ((wchar_t *) data.__outbuf)[-1] == L'\0')
  98         /* Don't count the NUL character in.  */
  99         --result;
 100     }
 101   else
 102     {
 103       /* This code is based on the safe assumption that all internal
 104          multi-byte encodings use the NUL byte only to mark the end
 105          of the string.  */
 106       data.__outbuf = (unsigned char *) dst;
 107       data.__outbufend = data.__outbuf + len * sizeof (wchar_t);
 108
 109       status = DL_CALL_FCT (fct,
 110                             (towc, &data, (const unsigned char **) src, srcend,
 111                              NULL, &dummy, 0, 1));
 112
 113       result = (wchar_t *) data.__outbuf - dst;
 114
 115       /* We have to determine whether the last character converted
 116          is the NUL character.  */
 117       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 118           && (assert (result > 0),
 119               ((wchar_t *) dst)[result - 1] == L'\0'))
 120         {
 121           assert (__mbsinit (data.__statep));
 122           *src = NULL;
 123           --result;
 124         }
 125     }
 126
 127   /* There must not be any problems with the conversion but illegal input
 128      characters.  */
 129   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
 130           || status == __GCONV_ILLEGAL_INPUT
 131           || status == __GCONV_INCOMPLETE_INPUT
 132           || status == __GCONV_FULL_OUTPUT);
 133
 134   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
 135       && status != __GCONV_EMPTY_INPUT && status != __GCONV_INCOMPLETE_INPUT)
 136     {
 137       result = (size_t) -1;
 138       __set_errno (EILSEQ);
 139     }
 140
 141   return result;
 142 }
 143 weak_alias (__mbsnrtowcs, mbsnrtowcs)