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glibc  2.9
wcscat_chk.c
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00001 /* Copyright (C) 1995, 1996, 1997, 2001, 2005 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <wchar.h>
00021 
00022 
00023 /* Append SRC on the end of DEST.  Check for overflows.  */
00024 wchar_t *
00025 __wcscat_chk (wchar_t *dest, const wchar_t *src, size_t destlen)
00026 {
00027   register wchar_t *s1 = dest;
00028   register const wchar_t *s2 = src;
00029   wchar_t c;
00030 
00031   /* Find the end of the string.  */
00032   do
00033     {
00034       if (__builtin_expect (destlen-- == 0, 0))
00035        __chk_fail ();
00036       c = *s1++;
00037     }
00038   while (c != L'\0');
00039 
00040   /* Make S1 point before the next character, so we can increment
00041      it while memory is read (wins on pipelined cpus).  */
00042   s1 -= 2;
00043   ++destlen;
00044 
00045   do
00046     {
00047       if (__builtin_expect (destlen-- == 0, 0))
00048        __chk_fail ();
00049       c = *s2++;
00050       *++s1 = c;
00051     }
00052   while (c != L'\0');
00053 
00054   return dest;
00055 }