1 /* $OpenBSD: lsearch.c,v 1.5 2014/07/18 04:16:09 matthew 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 static void *linear_base(const void *, const void *, size_t *, size_t,
41 cmp_fn_t, int);
42
43 void *
lsearch(const void * key,void * base,size_t * nelp,size_t width,cmp_fn_t compar)44 lsearch(const void *key, void *base, size_t *nelp, size_t width,
45 cmp_fn_t compar)
46 {
47
48 return(linear_base(key, base, nelp, width, compar, 1));
49 }
50
51 void *
lfind(const void * key,const void * base,size_t * nelp,size_t width,cmp_fn_t compar)52 lfind(const void *key, const void *base, size_t *nelp, size_t width,
53 cmp_fn_t compar)
54 {
55 return(linear_base(key, base, nelp, width, compar, 0));
56 }
57
58 static void *
linear_base(const void * key,const void * base,size_t * nelp,size_t width,cmp_fn_t compar,int add_flag)59 linear_base(const void *key, const void *base, size_t *nelp, size_t width,
60 cmp_fn_t compar, int add_flag)
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
69 if (!add_flag) /* key not found */
70 return(NULL);
71
72 /*
73 * The UNIX System User's Manual, 1986 edition claims that
74 * a NULL pointer is returned by lsearch with errno set
75 * appropriately, if there is not enough room in the table
76 * to add a new item. This can't be done as none of these
77 * routines have any method of determining the size of the
78 * table. This comment isn't in the 1986-87 System V
79 * manual.
80 */
81 ++*nelp;
82 memcpy((void *)end, key, width);
83 return((void *)end);
84 }
85