xref: /dflybsd-src/sys/libkern/strstr.c (revision 993dad295b86040e7818b7f0915a7d60e7dccdad)
1*993dad29SSascha Wildner /*
2*993dad29SSascha Wildner  * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
3*993dad29SSascha Wildner  *
4*993dad29SSascha Wildner  * Redistribution and use in source and binary forms, with or without
5*993dad29SSascha Wildner  * modification, are permitted provided that the following conditions
6*993dad29SSascha Wildner  * are met:
7*993dad29SSascha Wildner  *
8*993dad29SSascha Wildner  * 1. Redistributions of source code must retain the above copyright
9*993dad29SSascha Wildner  *    notice, this list of conditions and the following disclaimer.
10*993dad29SSascha Wildner  * 2. Redistributions in binary form must reproduce the above copyright
11*993dad29SSascha Wildner  *    notice, this list of conditions and the following disclaimer in
12*993dad29SSascha Wildner  *    the documentation and/or other materials provided with the
13*993dad29SSascha Wildner  *    distribution.
14*993dad29SSascha Wildner  * 3. Neither the name of The DragonFly Project nor the names of its
15*993dad29SSascha Wildner  *    contributors may be used to endorse or promote products derived
16*993dad29SSascha Wildner  *    from this software without specific, prior written permission.
17*993dad29SSascha Wildner  *
18*993dad29SSascha Wildner  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19*993dad29SSascha Wildner  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20*993dad29SSascha Wildner  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21*993dad29SSascha Wildner  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
22*993dad29SSascha Wildner  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23*993dad29SSascha Wildner  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
24*993dad29SSascha Wildner  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25*993dad29SSascha Wildner  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26*993dad29SSascha Wildner  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27*993dad29SSascha Wildner  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
28*993dad29SSascha Wildner  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29*993dad29SSascha Wildner  * SUCH DAMAGE.
30*993dad29SSascha Wildner  */
31*993dad29SSascha Wildner 
32*993dad29SSascha Wildner #include <sys/libkern.h>
33*993dad29SSascha Wildner 
34*993dad29SSascha Wildner char *
strstr(const char * s,const char * find)35*993dad29SSascha Wildner strstr(const char *s, const char *find)
36*993dad29SSascha Wildner {
37*993dad29SSascha Wildner 	char c, sc;
38*993dad29SSascha Wildner 	size_t len;
39*993dad29SSascha Wildner 
40*993dad29SSascha Wildner 	if ((c = *find++) != 0) {
41*993dad29SSascha Wildner 		len = strlen(find);
42*993dad29SSascha Wildner 		do {
43*993dad29SSascha Wildner 			do {
44*993dad29SSascha Wildner 				if ((sc = *s++) == 0)
45*993dad29SSascha Wildner 					return (NULL);
46*993dad29SSascha Wildner 			} while (sc != c);
47*993dad29SSascha Wildner 		} while (strncmp(s, find, len) != 0);
48*993dad29SSascha Wildner 		s--;
49*993dad29SSascha Wildner 	}
50*993dad29SSascha Wildner 	return (__DECONST(char *, s));
51*993dad29SSascha Wildner }
52