1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * Linear search algorithm, generalized from Knuth (6.1) Algorithm Q.
32 *
33 * This version no longer has anything to do with Knuth's Algorithm Q,
34 * which first copies the new element into the table, then looks for it.
35 * The assumption there was that the cost of checking for the end of the
36 * table before each comparison outweighed the cost of the comparison, which
37 * isn't true when an arbitrary comparison function must be called and when the
38 * copy itself takes a significant number of cycles.
39 * Actually, it has now reverted to Algorithm S, which is "simpler."
40 */
41
42 #pragma weak _lsearch = lsearch
43
44 #include "lint.h"
45 #include <mtlib.h>
46 #include <sys/types.h>
47 #include <stddef.h>
48 #include <string.h>
49 #include <thread.h>
50 #include <synch.h>
51
52 void *
lsearch(const void * ky,void * bs,size_t * nelp,size_t width,int (* compar)(const void *,const void *))53 lsearch(const void *ky, void *bs, size_t *nelp, size_t width,
54 int (*compar)(const void *, const void *))
55 {
56 char *key = (char *)ky;
57 char *base = (char *)bs;
58 char *next = base + *nelp * width; /* End of table */
59 void *res;
60
61 for (; base < next; base += width)
62 if ((*compar)(key, base) == 0)
63 return (base); /* Key found */
64 ++*nelp; /* Not found, add to table */
65 res = memcpy(base, key, width); /* base now == next */
66 return (res);
67 }
68