1 /*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 1996, 1997, 1998 5 * Sleepycat Software. All rights reserved. 6 */ 7 /* 8 * Copyright (c) 1995, 1996 9 * The Regents of the University of California. All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * Margo Seltzer. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #include "config.h" 44 45 #ifndef lint 46 static const char sccsid[] = "@(#)db_log2.c 10.5 (Sleepycat) 4/26/98"; 47 #endif /* not lint */ 48 49 #ifndef NO_SYSTEM_INCLUDES 50 #include <sys/types.h> 51 #endif 52 53 #include "db_int.h" 54 #include "common_ext.h" 55 56 /* 57 * PUBLIC: u_int32_t __db_log2 __P((u_int32_t)); 58 */ 59 u_int32_t 60 __db_log2(num) 61 u_int32_t num; 62 { 63 u_int32_t i, limit; 64 65 limit = 1; 66 for (i = 0; limit < num; limit = limit << 1, i++) 67 ; 68 return (i); 69 } 70