gnupg/util/memrchr.c

48 lines
1.3 KiB
C

/* memrchr.c - libc replacement function
* Copyright (C) 2005 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/*
memrchr() is a GNU function that might not be available everywhere.
It's basically the inverse of memchr() - search backwards in a
memory block for a particular character.
*/
#include <config.h>
#include <string.h>
/* There are many ways to optimize this, but this is a simple
unoptimized implementation. */
void *
memrchr(const void *s, int c, size_t n)
{
const unsigned char *start=s,*end=s;
end+=n-1;
while(end>=start)
{
if(*end==c)
return (void *)end;
else
end--;
}
return NULL;
}