debug/wcscat_chk.c

   1 /* Copyright (C) 1995, 1996, 1997, 2001, 2005 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
   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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <wchar.h>
  21
  22
  23 /* Append SRC on the end of DEST.  Check for overflows.  */
  24 wchar_t *
  25 __wcscat_chk (wchar_t *dest, const wchar_t *src, size_t destlen)
  26 {
  27   register wchar_t *s1 = dest;
  28   register const wchar_t *s2 = src;
  29   wchar_t c;
  30
  31   /* Find the end of the string.  */
  32   do
  33     {
  34       if (__builtin_expect (destlen-- == 0, 0))
  35         __chk_fail ();
  36       c = *s1++;
  37     }
  38   while (c != L'\0');
  39
  40   /* Make S1 point before the next character, so we can increment
  41      it while memory is read (wins on pipelined cpus).  */
  42   s1 -= 2;
  43   ++destlen;
  44
  45   do
  46     {
  47       if (__builtin_expect (destlen-- == 0, 0))
  48         __chk_fail ();
  49       c = *s2++;
  50       *++s1 = c;
  51     }
  52   while (c != L'\0');
  53
  54   return dest;
  55 }