63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
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/* $NetBSD: hash_log2.c,v 1.13 2008/09/11 12:33:55 joerg Exp $ */
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/*-
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* Copyright (c) 1990, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Margo Seltzer.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if HAVE_NBTOOL_CONFIG_H
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#include "nbtool_config.h"
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#endif
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: hash_log2.c,v 1.13 2008/09/11 12:33:55 joerg Exp $");
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#include <sys/types.h>
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#include <db.h>
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#include "hash.h"
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#include "page.h"
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#include "extern.h"
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uint32_t
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__log2(uint32_t num)
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{
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uint32_t i, limit;
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if (num == 0)
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return 0;
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--num;
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limit = 0;
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for (i = 0; limit < num; limit = limit * 2 + 1, i++)
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continue;
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return (i);
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}
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