memrchr.c

/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 2007, 2010-2014
 *	Todd C. Miller <[email protected]>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>

#ifndef HAVE_MEMRCHR

#include <sys/types.h>

#include <sudo_compat.h>

/*
 * Reverse memchr()
 * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
 */
void *
sudo_memrchr(const void *s, int c, size_t n)
{
    const unsigned char *cp;

    if (n != 0) {
	cp = (unsigned char *)s + n;
	do {
	    if (*(--cp) == (unsigned char)c)
		return (void *)cp;
	} while (--n != 0);
    }
    return (void *)0;
}
#endif /* HAVE_MEMRCHR */