wcsmbs/wcsnrtombs.c

   1 /* Copyright (C) 1996-2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <dlfcn.h>
  21 #include <errno.h>
  22 #include <gconv.h>
  23 #include <wchar.h>
  24 #include <wcsmbsload.h>
  25
  26 #include <sysdep.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 NWC wide character will be converted.  */
  39 size_t
  40 __wcsnrtombs (char *dst, const wchar_t **src, size_t nwc, size_t len,
  41               mbstate_t *ps)
  42 {
  43   struct __gconv_step_data data;
  44   const wchar_t *srcend;
  45   int status;
  46   size_t result;
  47   struct __gconv_step *tomb;
  48   const struct gconv_fcts *fcts;
  49
  50   /* Tell where we want the result.  */
  51   data.__invocation_counter = 0;
  52   data.__internal_use = 1;
  53   data.__flags = __GCONV_IS_LAST;
  54   data.__statep = ps ?: &state;
  55
  56   if (nwc == 0)
  57     return 0;
  58   srcend = *src + __wcsnlen (*src, nwc - 1) + 1;
  59
  60   /* Get the conversion functions.  */
  61   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  62
  63   /* Get the structure with the function pointers.  */
  64   tomb = fcts->tomb;
  65   __gconv_fct fct = tomb->__fct;
  66 #ifdef PTR_DEMANGLE
  67   if (tomb->__shlib_handle != NULL)
  68     PTR_DEMANGLE (fct);
  69 #endif
  70
  71   /* We have to handle DST == NULL special.  */
  72   if (dst == NULL)
  73     {
  74       mbstate_t temp_state;
  75       unsigned char buf[256];           /* Just an arbitrary value.  */
  76       const unsigned char *inbuf = (const unsigned char *) *src;
  77       size_t dummy;
  78
  79       temp_state = *data.__statep;
  80       data.__statep = &temp_state;
  81
  82       result = 0;
  83       data.__outbufend = buf + sizeof (buf);
  84
  85       do
  86         {
  87           data.__outbuf = buf;
  88
  89           status = DL_CALL_FCT (fct, (tomb, &data, &inbuf,
  90                                       (const unsigned char *) srcend, NULL,
  91                                       &dummy, 0, 1));
  92
  93           /* Count the number of bytes.  */
  94           result += data.__outbuf - buf;
  95         }
  96       while (status == __GCONV_FULL_OUTPUT);
  97
  98       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
  99           && data.__outbuf[-1] == '\0')
 100         /* Don't count the NUL character in.  */
 101         --result;
 102     }
 103   else
 104     {
 105       /* This code is based on the safe assumption that all internal
 106          multi-byte encodings use the NUL byte only to mark the end
 107          of the string.  */
 108       size_t dummy;
 109
 110       data.__outbuf = (unsigned char *) dst;
 111       data.__outbufend = (unsigned char *) dst + len;
 112
 113       status = DL_CALL_FCT (fct, (tomb, &data, (const unsigned char **) src,
 114                                   (const unsigned char *) srcend, NULL,
 115                                   &dummy, 0, 1));
 116
 117       /* Count the number of bytes.  */
 118       result = data.__outbuf - (unsigned char *) dst;
 119
 120       /* We have to determine whether the last character converted
 121          is the NUL character.  */
 122       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 123           && data.__outbuf[-1] == '\0')
 124         {
 125           assert (data.__outbuf != (unsigned char *) dst);
 126           assert (__mbsinit (data.__statep));
 127           *src = NULL;
 128           --result;
 129         }
 130     }
 131
 132   /* There must not be any problems with the conversion but illegal input
 133      characters.  */
 134   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
 135           || status == __GCONV_ILLEGAL_INPUT
 136           || status == __GCONV_INCOMPLETE_INPUT
 137           || status == __GCONV_FULL_OUTPUT);
 138
 139   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
 140       && status != __GCONV_EMPTY_INPUT)
 141     {
 142       result = (size_t) -1;
 143       __set_errno (EILSEQ);
 144     }
 145
 146   return result;
 147 }
 148 weak_alias (__wcsnrtombs, wcsnrtombs)