Mercurial > urweb

comparison src/c/memmem.c @ 914:782f0b4eea67

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
New release
author Adam Chlipala <adamc@hcoop.net>
date Tue, 25 Aug 2009 17:33:13 -0400
parents
children 7accd4546cf9
comparison
equal deleted inserted replaced
913:b26823138bf8 914:782f0b4eea67
1 /* $NetBSD$ */
2
3 /*-
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 __RCSID("$NetBSD$");
42 #endif /* LIBC_SCCS and not lint */
43
44 #if !defined(_KERNEL) && !defined(_STANDALONE)
45 #include <assert.h>
46 #include <string.h>
47 #else
48 #include <lib/libkern/libkern.h>
49 #define _DIAGASSERT(x) (void)0
50 #define NULL ((char *)0)
51 #endif
52
53 /*
54 * memmem() returns the location of the first occurence of data
55 * pattern b2 of size len2 in memory block b1 of size len1 or
56 * NULL if none is found.
57 */
58 void *
59 memmem(const void *b1, const void *b2, size_t len1, size_t len2)
60 {
61 /* Initialize search pointer */
62 char *sp = (char *) b1;
63
64 /* Initialize pattern pointer */
65 char *pp = (char *) b2;
66
67 /* Intialize end of search address space pointer */
68 char *eos = sp + len1 - len2;
69
70 /* Sanity check */
71 if(!(b1 && b2 && len1 && len2))
72 return NULL;
73
74 while (sp <= eos) {
75 if (*sp == *pp)
76 if (memcmp(sp, pp, len2) == 0)
77 return sp;
78
79 sp++;
80 }
81
82 return NULL;
83 }