/*
* Copyright (c) 2018 Jiri Svoboda
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup libc
* @{
*/
/**
* @file
* @brief Binary search.
*/
#include <bsearch.h>
#include <stddef.h>
/** Binary search.
*
* @param key Key to search for
* @param base Array of objects
* @param nmemb Number of objects in array
* @param size Size of each object
* @param compar Comparison function
*/
void *bsearch(const void *key, const void *base, size_t nmemb, size_t size,
int (*compar)(const void *, const void *))
{
size_t pividx;
const void *pivot;
int r;
while (nmemb != 0) {
pividx = nmemb / 2;
pivot = base + size * pividx;
r = compar(key, pivot);
if (r == 0)
return (void *)pivot;
if (r < 0) {
/* Now only look at members preceding pivot */
nmemb = pividx;
} else {
/* Now only look at members following pivot */
nmemb = nmemb - pividx - 1;
base += size * (pividx + 1);
}
}
return NULL;
}
/** @}
*/