1  /* Copyright (C) 1995-2023 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 <wchar.h>
      19  
      20  
      21  /* Append SRC on the end of DEST.  Check for overflows.  */
      22  wchar_t *
      23  __wcscat_chk (wchar_t *dest, const wchar_t *src, size_t destlen)
      24  {
      25    wchar_t *s1 = dest;
      26    const wchar_t *s2 = src;
      27    wchar_t c;
      28  
      29    /* Find the end of the string.  */
      30    do
      31      {
      32        if (__glibc_unlikely (destlen-- == 0))
      33  	__chk_fail ();
      34        c = *s1++;
      35      }
      36    while (c != L'\0');
      37  
      38    /* Make S1 point before the next character, so we can increment
      39       it while memory is read (wins on pipelined cpus).	*/
      40    s1 -= 2;
      41    ++destlen;
      42  
      43    do
      44      {
      45        if (__glibc_unlikely (destlen-- == 0))
      46  	__chk_fail ();
      47        c = *s2++;
      48        *++s1 = c;
      49      }
      50    while (c != L'\0');
      51  
      52    return dest;
      53  }