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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984 AT&T */
/* All Rights Reserved */
#pragma ident "%Z%%M% %I% %E% SMI" /* from S5R2 1.5 */
/*LINTLIBRARY*/
/*
* Binary search algorithm, generalized from Knuth (6.2.1) Algorithm B.
*
*/
typedef char *POINTER;
POINTER
bsearch(key, base, nel, width, compar)
POINTER key; /* Key to be located */
POINTER base; /* Beginning of table */
unsigned nel; /* Number of elements in the table */
unsigned width; /* Width of an element (bytes) */
int (*compar)(); /* Comparison function */
{
int two_width = width + width;
POINTER last = base + width * (nel - 1); /* Last element in table */
while (last >= base) {
register POINTER p = base + width * ((last - base)/two_width);
register int res = (*compar)(key, p);
if (res == 0)
return (p); /* Key found */
if (res < 0)
last = p - width;
else
base = p + width;
}
return ((POINTER) 0); /* Key not found */
}
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