hash_log2.c revision 256281
125184Sjkh/*- 2113674Smtm * Copyright (c) 1990, 1993, 1994 3113674Smtm * The Regents of the University of California. All rights reserved. 4113674Smtm * 5113674Smtm * This code is derived from software contributed to Berkeley by 6113674Smtm * Margo Seltzer. 7113674Smtm * 8113674Smtm * Redistribution and use in source and binary forms, with or without 9113674Smtm * modification, are permitted provided that the following conditions 10113674Smtm * are met: 11113674Smtm * 1. Redistributions of source code must retain the above copyright 12113674Smtm * notice, this list of conditions and the following disclaimer. 13113674Smtm * 2. Redistributions in binary form must reproduce the above copyright 14113674Smtm * notice, this list of conditions and the following disclaimer in the 15113674Smtm * documentation and/or other materials provided with the distribution. 16113674Smtm * 4. Neither the name of the University nor the names of its contributors 17113674Smtm * may be used to endorse or promote products derived from this software 18113674Smtm * without specific prior written permission. 19113674Smtm * 20113674Smtm * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21113674Smtm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22113674Smtm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23113674Smtm * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24113674Smtm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2550472Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2666830Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2725184Sjkh * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28113674Smtm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29113674Smtm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30113674Smtm * SUCH DAMAGE. 31113674Smtm */ 3225184Sjkh 33178356Ssam#if defined(LIBC_SCCS) && !defined(lint) 34197147Shrsstatic char sccsid[] = "@(#)hash_log2.c 8.2 (Berkeley) 5/31/94"; 35197147Shrs#endif /* LIBC_SCCS and not lint */ 36178356Ssam#include <sys/cdefs.h> 37178356Ssam__FBSDID("$FreeBSD: stable/10/lib/libc/db/hash/hash_log2.c 190484 2009-03-28 05:45:29Z delphij $"); 38178356Ssam 39178356Ssam#include <db.h> 40178356Ssam#include "hash.h" 41178356Ssam#include "page.h" 42178356Ssam#include "extern.h" 43178356Ssam 44178356Ssamu_int32_t 45178356Ssam__log2(u_int32_t num) 46178356Ssam{ 47222515Sbz u_int32_t i, limit; 48222515Sbz 49222515Sbz limit = 1; 50197139Shrs for (i = 0; limit < num; limit = limit << 1, i++); 51178356Ssam return (i); 52178356Ssam} 53178356Ssam