xref: /freebsd/lib/libc/string/memrchr.c (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
1 /*	$OpenBSD: memrchr.c,v 1.2 2007/11/27 16:22:12 martynas Exp $	*/
2 
3 /*
4  * Copyright (c) 2007 Todd C. Miller <Todd.Miller@courtesan.com>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  *
18  * $FreeBSD$
19  */
20 
21 #include <string.h>
22 
23 /*
24  * Reverse memchr()
25  * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
26  */
27 void *
28 memrchr(const void *s, int c, size_t n)
29 {
30 	const unsigned char *cp;
31 
32 	if (n != 0) {
33 		cp = (unsigned char *)s + n;
34 		do {
35 			if (*(--cp) == (unsigned char)c)
36 				return((void *)cp);
37 		} while (--n != 0);
38 	}
39 	return(NULL);
40 }
41