wcsmbs/mbsnrtowcs.c

   1 /* Copyright (C) 1996-2015 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 (dst, src, nmc, len, ps)
  42      wchar_t *dst;
  43      const char **src;
  44      size_t nmc;
  45      size_t len;
  46      mbstate_t *ps;
  47 {
  48   const unsigned char *srcend;
  49   struct __gconv_step_data data;
  50   size_t result;
  51   int status;
  52   struct __gconv_step *towc;
  53   size_t dummy;
  54   const struct gconv_fcts *fcts;
  55
  56   /* Tell where we want the result.  */
  57   data.__invocation_counter = 0;
  58   data.__internal_use = 1;
  59   data.__flags = __GCONV_IS_LAST;
  60   data.__statep = ps ?: &state;
  61
  62   if (nmc == 0)
  63     return 0;
  64   srcend = (const unsigned char *) *src + __strnlen (*src, nmc - 1) + 1;
  65
  66   /* Get the conversion functions.  */
  67   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  68
  69   /* Get the structure with the function pointers.  */
  70   towc = fcts->towc;
  71   __gconv_fct fct = towc->__fct;
  72 #ifdef PTR_DEMANGLE
  73   if (towc->__shlib_handle != NULL)
  74     PTR_DEMANGLE (fct);
  75 #endif
  76
  77   /* We have to handle DST == NULL special.  */
  78   if (dst == NULL)
  79     {
  80       mbstate_t temp_state;
  81       wchar_t buf[64];          /* Just an arbitrary size.  */
  82       const unsigned char *inbuf = (const unsigned char *) *src;
  83
  84       temp_state = *data.__statep;
  85       data.__statep = &temp_state;
  86
  87       result = 0;
  88       data.__outbufend = (unsigned char *) buf + sizeof (buf);
  89       do
  90         {
  91           data.__outbuf = (unsigned char *) buf;
  92
  93           status = DL_CALL_FCT (fct, (towc, &data, &inbuf, srcend, NULL,
  94                                       &dummy, 0, 1));
  95
  96           result += (wchar_t *) data.__outbuf - buf;
  97         }
  98       while (status == __GCONV_FULL_OUTPUT);
  99
 100       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 101           && ((wchar_t *) data.__outbuf)[-1] == L'\0')
 102         /* Don't count the NUL character in.  */
 103         --result;
 104     }
 105   else
 106     {
 107       /* This code is based on the safe assumption that all internal
 108          multi-byte encodings use the NUL byte only to mark the end
 109          of the string.  */
 110       data.__outbuf = (unsigned char *) dst;
 111       data.__outbufend = data.__outbuf + len * sizeof (wchar_t);
 112
 113       status = DL_CALL_FCT (fct,
 114                             (towc, &data, (const unsigned char **) src, srcend,
 115                              NULL, &dummy, 0, 1));
 116
 117       result = (wchar_t *) data.__outbuf - dst;
 118
 119       /* We have to determine whether the last character converted
 120          is the NUL character.  */
 121       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 122           && (assert (result > 0),
 123               ((wchar_t *) dst)[result - 1] == L'\0'))
 124         {
 125           assert (__mbsinit (data.__statep));
 126           *src = NULL;
 127           --result;
 128         }
 129     }
 130
 131   /* There must not be any problems with the conversion but illegal input
 132      characters.  */
 133   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
 134           || status == __GCONV_ILLEGAL_INPUT
 135           || status == __GCONV_INCOMPLETE_INPUT
 136           || status == __GCONV_FULL_OUTPUT);
 137
 138   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
 139       && status != __GCONV_EMPTY_INPUT && status != __GCONV_INCOMPLETE_INPUT)
 140     {
 141       result = (size_t) -1;
 142       __set_errno (EILSEQ);
 143     }
 144
 145   return result;
 146 }
 147 weak_alias (__mbsnrtowcs, mbsnrtowcs)