wcsmbs/wcsrtombs.c

   1 /* Copyright (C) 1996-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <assert.h>
  19 #include <dlfcn.h>
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <gconv.h>
  23 #include <wchar.h>
  24 #include <wcsmbsload.h>
  25
  26 #include <pointer_guard.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 size_t
  37 __wcsrtombs (char *dst, const wchar_t **src, size_t len, mbstate_t *ps)
  38 {
  39   struct __gconv_step_data data;
  40   int status;
  41   size_t result;
  42   struct __gconv_step *tomb;
  43   const struct gconv_fcts *fcts;
  44
  45   /* Tell where we want the result.  */
  46   data.__invocation_counter = 0;
  47   data.__internal_use = 1;
  48   data.__flags = __GCONV_IS_LAST;
  49   data.__statep = ps ?: &state;
  50
  51   /* Get the conversion functions.  */
  52   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  53
  54   /* Get the structure with the function pointers.  */
  55   tomb = fcts->tomb;
  56   __gconv_fct fct = tomb->__fct;
  57   if (tomb->__shlib_handle != NULL)
  58     PTR_DEMANGLE (fct);
  59
  60   /* We have to handle DST == NULL special.  */
  61   if (dst == NULL)
  62     {
  63       mbstate_t temp_state;
  64       unsigned char buf[256];           /* Just an arbitrary value.  */
  65       const wchar_t *srcend = *src + __wcslen (*src) + 1;
  66       const unsigned char *inbuf = (const unsigned char *) *src;
  67       size_t dummy;
  68
  69       temp_state = *data.__statep;
  70       data.__statep = &temp_state;
  71
  72       result = 0;
  73       data.__outbufend = buf + sizeof (buf);
  74
  75       do
  76         {
  77           data.__outbuf = buf;
  78
  79           status = DL_CALL_FCT (fct, (tomb, &data, &inbuf,
  80                                       (const unsigned char *) srcend, NULL,
  81                                       &dummy, 0, 1));
  82
  83           /* Count the number of bytes.  */
  84           result += data.__outbuf - buf;
  85         }
  86       while (status == __GCONV_FULL_OUTPUT);
  87
  88       if (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
  89         {
  90           /* There better should be a NUL byte at the end.  */
  91           assert (data.__outbuf[-1] == '\0');
  92           /* Don't count the NUL character in.  */
  93           --result;
  94         }
  95     }
  96   else
  97     {
  98       /* This code is based on the safe assumption that all internal
  99          multi-byte encodings use the NUL byte only to mark the end
 100          of the string.  */
 101       const wchar_t *srcend = *src + __wcsnlen (*src, len) + 1;
 102       size_t dummy;
 103
 104       data.__outbuf = (unsigned char *) dst;
 105       data.__outbufend = (unsigned char *) dst + len;
 106
 107       status = DL_CALL_FCT (fct, (tomb, &data, (const unsigned char **) src,
 108                                   (const unsigned char *) srcend, NULL,
 109                                   &dummy, 0, 1));
 110
 111       /* Count the number of bytes.  */
 112       result = data.__outbuf - (unsigned char *) dst;
 113
 114       /* We have to determine whether the last character converted
 115          is the NUL character.  */
 116       if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
 117           && data.__outbuf[-1] == '\0')
 118         {
 119           assert (data.__outbuf != (unsigned char *) dst);
 120           assert (__mbsinit (data.__statep));
 121           *src = NULL;
 122           --result;
 123         }
 124     }
 125
 126   /* There must not be any problems with the conversion but illegal input
 127      characters.  */
 128   assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
 129           || status == __GCONV_ILLEGAL_INPUT
 130           || status == __GCONV_INCOMPLETE_INPUT
 131           || status == __GCONV_FULL_OUTPUT);
 132
 133   if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
 134       && status != __GCONV_EMPTY_INPUT)
 135     {
 136       result = (size_t) -1;
 137       __set_errno (EILSEQ);
 138     }
 139
 140   return result;
 141 }
 142 weak_alias (__wcsrtombs, wcsrtombs)