blob: 18b445b010c35a87be7480192d5aefa62583ac03 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
/*
* A generic implementation of binary search for the Linux kernel
*
* Copyright (C) 2008-2009 Ksplice, Inc.
* Author: Tim Abbott <tabbott@ksplice.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; version 2.
*/
#include <linux/export.h>
#include <linux/bsearch.h>
/*
* bsearch - binary search an array of elements
* @key: pointer to item being searched for
* @base: pointer to first element to search
* @num: number of elements
* @size: size of each element
* @cmp: pointer to comparison function
*
* This function does a binary search on the given array. The
* contents of the array should already be in ascending sorted order
* under the provided comparison function.
*
* Note that the key need not have the same type as the elements in
* the array, e.g. key could be a string and the comparison function
* could compare the string with the struct's name field. However, if
* the key and elements in the array are of the same type, you can use
* the same comparison function for both sort() and bsearch().
*/
void *bsearch(const void *key, const void *base, size_t num, size_t size,
int (*cmp)(const void *key, const void *elt))
{
const char *pivot;
int result;
while (num > 0) {
pivot = base + (num >> 1) * size;
result = cmp(key, pivot);
if (result == 0)
return (void *)pivot;
if (result > 0) {
base = pivot + size;
num--;
}
num >>= 1;
}
return NULL;
}
EXPORT_SYMBOL(bsearch);
|
