wcsmbs/wcrtomb.c

   1 /* Copyright (C) 1996-2024 Free Software Foundation, Inc.
   2    Copyright The GNU Toolchain Authors.
   3    This file is part of the GNU C Library.
   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 <stdlib.h>
  24 #include <string.h>
  25 #include <wchar.h>
  26 #include <wcsmbsload.h>
  27
  28 #include <pointer_guard.h>
  29
  30 #ifndef EILSEQ
  31 # define EILSEQ EINVAL
  32 #endif
  33
  34
  35 /* This is the private state used if PS is NULL.  */
  36 static mbstate_t state;
  37
  38 size_t
  39 __wcrtomb_internal (char *s, wchar_t wc, mbstate_t *ps, size_t s_size)
  40 {
  41   char buf[MB_LEN_MAX];
  42   struct __gconv_step_data data;
  43   int status;
  44   size_t result;
  45   size_t dummy;
  46   const struct gconv_fcts *fcts;
  47
  48   /* Set information for this step.  */
  49   data.__invocation_counter = 0;
  50   data.__internal_use = 1;
  51   data.__flags = __GCONV_IS_LAST;
  52   data.__statep = ps ?: &state;
  53
  54   /* A first special case is if S is NULL.  This means put PS in the
  55      initial state.  */
  56   if (s == NULL)
  57     wc = L'\0';
  58
  59   /* Tell where we want to have the result.  */
  60   data.__outbuf = (unsigned char *) buf;
  61   data.__outbufend = (unsigned char *) buf + sizeof buf;
  62
  63   /* Get the conversion functions.  */
  64   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  65   __gconv_fct fct = fcts->tomb->__fct;
  66   if (fcts->tomb->__shlib_handle != NULL)
  67     PTR_DEMANGLE (fct);
  68
  69   /* If WC is the NUL character we write into the output buffer the byte
  70      sequence necessary for PS to get into the initial state, followed
  71      by a NUL byte.  */
  72   if (wc == L'\0')
  73     {
  74       status = DL_CALL_FCT (fct, (fcts->tomb, &data, NULL, NULL,
  75                                   NULL, &dummy, 1, 1));
  76
  77       if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
  78         *data.__outbuf++ = '\0';
  79     }
  80   else
  81     {
  82       /* Do a normal conversion.  */
  83       const unsigned char *inbuf = (const unsigned char *) &wc;
  84
  85       status = DL_CALL_FCT (fct,
  86                             (fcts->tomb, &data, &inbuf,
  87                              inbuf + sizeof (wchar_t), NULL, &dummy, 0, 1));
  88     }
  89
  90   /* There must not be any problems with the conversion but illegal input
  91      characters.  The output buffer must be large enough, otherwise the
  92      definition of MB_CUR_MAX is not correct.  All the other possible
  93      errors also must not happen.  */
  94   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
  95           || status == __GCONV_ILLEGAL_INPUT
  96           || status == __GCONV_INCOMPLETE_INPUT
  97           || status == __GCONV_FULL_OUTPUT);
  98
  99   if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
 100       || status == __GCONV_FULL_OUTPUT)
 101     {
 102       result = data.__outbuf - (unsigned char *) buf;
 103
 104       if (s != NULL)
 105         {
 106           if (result > s_size)
 107             __chk_fail ();
 108
 109           memcpy (s, buf, result);
 110         }
 111     }
 112   else
 113     {
 114       result = (size_t) -1;
 115       __set_errno (EILSEQ);
 116     }
 117
 118   return result;
 119 }
 120
 121 size_t
 122 __wcrtomb (char *s, wchar_t wc, mbstate_t *ps)
 123 {
 124   return __wcrtomb_internal (s, wc, ps, (size_t) -1);
 125 }
 126 weak_alias (__wcrtomb, wcrtomb)
 127 libc_hidden_weak (wcrtomb)