summaryrefslogtreecommitdiff
path: root/src/lib/libc/stdlib/bsearch.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/lib/libc/stdlib/bsearch.c')
-rw-r--r--src/lib/libc/stdlib/bsearch.c68
1 files changed, 0 insertions, 68 deletions
diff --git a/src/lib/libc/stdlib/bsearch.c b/src/lib/libc/stdlib/bsearch.c
deleted file mode 100644
index 59d478e7eb..0000000000
--- a/src/lib/libc/stdlib/bsearch.c
+++ /dev/null
@@ -1,68 +0,0 @@
1/* $OpenBSD: bsearch.c,v 1.8 2016/10/22 19:19:34 tb Exp $ */
2/*
3 * Copyright (c) 1990 Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <stdlib.h>
32
33/*
34 * Perform a binary search.
35 *
36 * The code below is a bit sneaky. After a comparison fails, we
37 * divide the work in half by moving either left or right. If lim
38 * is odd, moving left simply involves halving lim: e.g., when lim
39 * is 5 we look at item 2, so we change lim to 2 so that we will
40 * look at items 0 & 1. If lim is even, the same applies. If lim
41 * is odd, moving right again involves halving lim, this time moving
42 * the base up one item past p: e.g., when lim is 5 we change base
43 * to item 3 and make lim 2 so that we will look at items 3 and 4.
44 * If lim is even, however, we have to shrink it by one before
45 * halving: e.g., when lim is 4, we still looked at item 2, so we
46 * have to make lim 3, then halve, obtaining 1, so that we will only
47 * look at item 3.
48 */
49void *
50bsearch(const void *key, const void *base0, size_t nmemb, size_t size,
51 int (*compar)(const void *, const void *))
52{
53 const char *base = base0;
54 int lim, cmp;
55 const void *p;
56
57 for (lim = nmemb; lim != 0; lim >>= 1) {
58 p = base + (lim >> 1) * size;
59 cmp = (*compar)(key, p);
60 if (cmp == 0)
61 return ((void *)p);
62 if (cmp > 0) { /* key > p: move right */
63 base = (char *)p + size;
64 lim--;
65 } /* else move left */
66 }
67 return (NULL);
68}