1 /* $NetBSD: strnstr.c,v 1.1 2014/09/24 22:21:33 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org>
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Chris Torek.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)strstr.c 8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: strnstr.c,v 1.1 2014/09/24 22:21:33 christos Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44 /* FreeBSD: head/lib/libc/string/strnstr.c 251069 2013-05-28 20:57:40Z emaste */
45
46 #include <string.h>
47
48 /*
49 * Find the first occurrence of find in s, where the search is limited to the
50 * first slen characters of s.
51 */
52 char *
strnstr(const char * s,const char * find,size_t slen)53 strnstr(const char *s, const char *find, size_t slen)
54 {
55 char c, sc;
56 size_t len;
57
58 if ((c = *find++) != '\0') {
59 len = strlen(find);
60 do {
61 do {
62 if (slen-- < 1 || (sc = *s++) == '\0')
63 return NULL;
64 } while (sc != c);
65 if (len > slen)
66 return NULL;
67 } while (strncmp(s, find, len) != 0);
68 s--;
69 }
70 return __UNCONST(s);
71 }
72