xref: /freebsd-src/lib/libc/string/memrchr.c (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
1*82e45205SXin LI /*	$OpenBSD: memrchr.c,v 1.2 2007/11/27 16:22:12 martynas Exp $	*/
2*82e45205SXin LI 
3*82e45205SXin LI /*
4*82e45205SXin LI  * Copyright (c) 2007 Todd C. Miller <Todd.Miller@courtesan.com>
5*82e45205SXin LI  *
6*82e45205SXin LI  * Permission to use, copy, modify, and distribute this software for any
7*82e45205SXin LI  * purpose with or without fee is hereby granted, provided that the above
8*82e45205SXin LI  * copyright notice and this permission notice appear in all copies.
9*82e45205SXin LI  *
10*82e45205SXin LI  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11*82e45205SXin LI  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12*82e45205SXin LI  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13*82e45205SXin LI  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14*82e45205SXin LI  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15*82e45205SXin LI  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16*82e45205SXin LI  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17*82e45205SXin LI  */
18*82e45205SXin LI 
19*82e45205SXin LI #include <string.h>
20*82e45205SXin LI 
21*82e45205SXin LI /*
22*82e45205SXin LI  * Reverse memchr()
23*82e45205SXin LI  * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
24*82e45205SXin LI  */
25*82e45205SXin LI void *
memrchr(const void * s,int c,size_t n)26*82e45205SXin LI memrchr(const void *s, int c, size_t n)
27*82e45205SXin LI {
28*82e45205SXin LI 	const unsigned char *cp;
29*82e45205SXin LI 
30*82e45205SXin LI 	if (n != 0) {
31*82e45205SXin LI 		cp = (unsigned char *)s + n;
32*82e45205SXin LI 		do {
33*82e45205SXin LI 			if (*(--cp) == (unsigned char)c)
34*82e45205SXin LI 				return((void *)cp);
35*82e45205SXin LI 		} while (--n != 0);
36*82e45205SXin LI 	}
37*82e45205SXin LI 	return(NULL);
38*82e45205SXin LI }
39