10Sstevel@tonic-gate /*
20Sstevel@tonic-gate * CDDL HEADER START
30Sstevel@tonic-gate *
40Sstevel@tonic-gate * The contents of this file are subject to the terms of the
53836Sat204353 * Common Development and Distribution License (the "License").
63836Sat204353 * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate *
80Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate * See the License for the specific language governing permissions
110Sstevel@tonic-gate * and limitations under the License.
120Sstevel@tonic-gate *
130Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate *
190Sstevel@tonic-gate * CDDL HEADER END
200Sstevel@tonic-gate */
21*6812Sraf
22*6812Sraf /*
23*6812Sraf * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24*6812Sraf * Use is subject to license terms.
25*6812Sraf */
26*6812Sraf
270Sstevel@tonic-gate /* Copyright (c) 1988 AT&T */
280Sstevel@tonic-gate /* All Rights Reserved */
290Sstevel@tonic-gate
300Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
310Sstevel@tonic-gate
320Sstevel@tonic-gate /*
330Sstevel@tonic-gate * Binary search algorithm, generalized from Knuth (6.2.1) Algorithm B.
340Sstevel@tonic-gate */
350Sstevel@tonic-gate
360Sstevel@tonic-gate #if !defined(_BOOT) && !defined(_KMDB)
37*6812Sraf #include "lint.h"
380Sstevel@tonic-gate #endif /* !_BOOT && !_KMDB */
390Sstevel@tonic-gate #include <stddef.h>
400Sstevel@tonic-gate #include <stdlib.h>
410Sstevel@tonic-gate #include <sys/types.h>
420Sstevel@tonic-gate
430Sstevel@tonic-gate void *
bsearch(const void * ky,const void * bs,size_t nel,size_t width,int (* compar)(const void *,const void *))440Sstevel@tonic-gate bsearch(const void *ky, /* Key to be located */
450Sstevel@tonic-gate const void *bs, /* Beginning of table */
460Sstevel@tonic-gate size_t nel, /* Number of elements in the table */
470Sstevel@tonic-gate size_t width, /* Width of an element (bytes) */
480Sstevel@tonic-gate int (*compar)(const void *, const void *)) /* Comparison function */
490Sstevel@tonic-gate {
500Sstevel@tonic-gate char *base;
513836Sat204353 size_t two_width;
520Sstevel@tonic-gate char *last; /* Last element in table */
530Sstevel@tonic-gate
540Sstevel@tonic-gate if (nel == 0)
550Sstevel@tonic-gate return (NULL);
560Sstevel@tonic-gate
570Sstevel@tonic-gate base = (char *)bs;
580Sstevel@tonic-gate two_width = width + width;
590Sstevel@tonic-gate last = base + width * (nel - 1);
600Sstevel@tonic-gate
610Sstevel@tonic-gate while (last >= base) {
620Sstevel@tonic-gate
630Sstevel@tonic-gate char *p = base + width * ((last - base)/two_width);
640Sstevel@tonic-gate int res = (*compar)(ky, (void *)p);
650Sstevel@tonic-gate
660Sstevel@tonic-gate if (res == 0)
670Sstevel@tonic-gate return (p); /* Key found */
680Sstevel@tonic-gate if (res < 0)
690Sstevel@tonic-gate last = p - width;
700Sstevel@tonic-gate else
710Sstevel@tonic-gate base = p + width;
720Sstevel@tonic-gate }
730Sstevel@tonic-gate return (NULL); /* Key not found */
740Sstevel@tonic-gate }
75