xref: /freebsd/lib/libc/string/memrchr.c (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
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 
19 #include <string.h>
20 
21 /*
22  * Reverse memchr()
23  * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
24  */
25 void *
26 memrchr(const void *s, int c, size_t n)
27 {
28 	const unsigned char *cp;
29 
30 	if (n != 0) {
31 		cp = (unsigned char *)s + n;
32 		do {
33 			if (*(--cp) == (unsigned char)c)
34 				return((void *)cp);
35 		} while (--n != 0);
36 	}
37 	return(NULL);
38 }
39