1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * Binary search algorithm, generalized from Knuth (6.2.1) Algorithm B. 32 */ 33 34 #if !defined(_BOOT) && !defined(_KMDB) 35 #include "lint.h" 36 #endif /* !_BOOT && !_KMDB */ 37 #include <stddef.h> 38 #include <stdlib.h> 39 #include <sys/types.h> 40 41 void * 42 bsearch(const void *ky, /* Key to be located */ 43 const void *bs, /* Beginning of table */ 44 size_t nel, /* Number of elements in the table */ 45 size_t width, /* Width of an element (bytes) */ 46 int (*compar)(const void *, const void *)) /* Comparison function */ 47 { 48 char *base; 49 size_t two_width; 50 char *last; /* Last element in table */ 51 52 if (nel == 0) 53 return (NULL); 54 55 base = (char *)bs; 56 two_width = width + width; 57 last = base + width * (nel - 1); 58 59 while (last >= base) { 60 61 char *p = base + width * ((last - base)/two_width); 62 int res = (*compar)(ky, (void *)p); 63 64 if (res == 0) 65 return (p); /* Key found */ 66 if (res < 0) 67 last = p - width; 68 else 69 base = p + width; 70 } 71 return (NULL); /* Key not found */ 72 } 73