1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Roger L. Snyder.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 #if defined(LIBC_SCCS) && !defined(lint)
35 #if 0
36 static char sccsid[] = "@(#)lsearch.c 8.1 (Berkeley) 6/4/93";
37 #else
38 __RCSID("$NetBSD: lsearch.c,v 1.7 2012/06/25 22:32:45 abs Exp $");
39 #endif
40 #endif /* LIBC_SCCS and not lint */
41
42 #include <sys/types.h>
43
44 #include <assert.h>
45 #include <errno.h>
46 #include <string.h>
47 #include <search.h>
48
49 typedef int (*cmp_fn_t)(const void *, const void *);
50 static void *linear_base(const void *, void *, size_t *, size_t,
51 cmp_fn_t, int);
52
53 void *
lsearch(const void * key,void * base,size_t * nelp,size_t width,cmp_fn_t compar)54 lsearch(const void *key, void *base, size_t *nelp, size_t width,
55 cmp_fn_t compar)
56 {
57
58 _DIAGASSERT(key != NULL);
59 _DIAGASSERT(base != NULL);
60 _DIAGASSERT(compar != NULL);
61
62 return(linear_base(key, base, nelp, width, compar, 1));
63 }
64
65 void *
lfind(const void * key,const void * base,size_t * nelp,size_t width,cmp_fn_t compar)66 lfind(const void *key, const void *base, size_t *nelp, size_t width,
67 cmp_fn_t compar)
68 {
69
70 _DIAGASSERT(key != NULL);
71 _DIAGASSERT(base != NULL);
72 _DIAGASSERT(compar != NULL);
73
74 return(linear_base(key, __UNCONST(base), nelp, width, compar, 0));
75 }
76
77 static void *
linear_base(const void * key,void * base,size_t * nelp,size_t width,cmp_fn_t compar,int add_flag)78 linear_base(const void *key, void *base, size_t *nelp, size_t width,
79 cmp_fn_t compar, int add_flag)
80 {
81 char *element, *end;
82
83 _DIAGASSERT(key != NULL);
84 _DIAGASSERT(base != NULL);
85 _DIAGASSERT(compar != NULL);
86
87 end = (char *)base + *nelp * width;
88 for (element = (char *)base; element < end; element += width)
89 if (!compar(element, key)) /* key found */
90 return element;
91
92 if (!add_flag) /* key not found */
93 return(NULL);
94
95 /*
96 * The UNIX System User's Manual, 1986 edition claims that
97 * a NULL pointer is returned by lsearch with errno set
98 * appropriately, if there is not enough room in the table
99 * to add a new item. This can't be done as none of these
100 * routines have any method of determining the size of the
101 * table. This comment isn't in the 1986-87 System V
102 * manual.
103 */
104 ++*nelp;
105 memcpy(end, key, width);
106 return end;
107 }
108