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1 /*	$OpenBSD: lsearch.c,v 1.7 2021/12/08 22:06:28 cheloha Exp $	*/
2 
3 /*
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Roger L. Snyder.
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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/types.h>
36 #include <string.h>
37 #include <search.h>
38 
39 typedef int (*cmp_fn_t)(const void *, const void *);
40 
41 void *
lsearch(const void * key,void * base,size_t * nelp,size_t width,cmp_fn_t compar)42 lsearch(const void *key, void *base, size_t *nelp, size_t width,
43     	cmp_fn_t compar)
44 {
45 	void *element = lfind(key, base, nelp, width, compar);
46 
47 	/*
48 	 * Use memmove(3) to ensure the key is copied cleanly into the
49 	 * array, even if the key overlaps with the end of the array.
50 	 */
51 	if (element == NULL) {
52 		element = memmove((char *)base + *nelp * width, key, width);
53 		*nelp += 1;
54 	}
55 	return element;
56 }
57 
58 void *
lfind(const void * key,const void * base,size_t * nelp,size_t width,cmp_fn_t compar)59 lfind(const void *key, const void *base, size_t *nelp, size_t width,
60 	cmp_fn_t compar)
61 {
62 	const char *element, *end;
63 
64 	end = (const char *)base + *nelp * width;
65 	for (element = base; element < end; element += width)
66 		if (!compar(key, element))		/* key found */
67 			return((void *)element);
68 	return NULL;
69 }
70 DEF_WEAK(lfind);
71