hash_log2.c revision 189291 
150472Speter/*-
239145Sbrian * Copyright (c) 1990, 1993, 1994
3149Srgrimes *	The Regents of the University of California.  All rights reserved.
4105053Srwatson *
5105055Srwatson * This code is derived from software contributed to Berkeley by
6105055Srwatson * Margo Seltzer.
7105055Srwatson *
837Srgrimes * Redistribution and use in source and binary forms, with or without
925376Sjkh * modification, are permitted provided that the following conditions
1037Srgrimes * are met:
1137Srgrimes * 1. Redistributions of source code must retain the above copyright
121280Sjkh *    notice, this list of conditions and the following disclaimer.
1337Srgrimes * 2. Redistributions in binary form must reproduce the above copyright
14170566Sceri *    notice, this list of conditions and the following disclaimer in the
15105055Srwatson *    documentation and/or other materials provided with the distribution.
1698696Sdes * 4. Neither the name of the University nor the names of its contributors
1786510Sgshapiro *    may be used to endorse or promote products derived from this software
1886510Sgshapiro *    without specific prior written permission.
19241823Smarcel *
20105131Srwatson * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
2141441Sdillon * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22255597Sdes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23126810Smlaier * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24126810Smlaier * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25130953Smlaier * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26147062Sbrooks * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
271642Sache * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2814594Sphk * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2929082Sbrian * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30155350Srwatson * SUCH DAMAGE.
3185455Sache */
32218046Spjd
338573Srgrimes#if defined(LIBC_SCCS) && !defined(lint)
348539Sachestatic char sccsid[] = "@(#)hash_log2.c	8.2 (Berkeley) 5/31/94";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: head/lib/libc/db/hash/hash_log2.c 189291 2009-03-02 23:47:18Z delphij $");
38
39#include <sys/types.h>
40
41#include <db.h>
42
43u_int32_t
44__log2(u_int32_t num)
45{
46	u_int32_t i, limit;
47
48	limit = 1;
49	for (i = 0; limit < num; limit = limit << 1, i++);
50	return (i);
51}
52