2011-04-27 10:05:43 +00:00
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/****************************************************************************
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**
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2013-01-02 11:13:29 +00:00
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** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
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2012-09-19 12:28:29 +00:00
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** Contact: http://www.qt-project.org/legal
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2011-04-27 10:05:43 +00:00
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**
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** This file is part of the test suite of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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2012-09-19 12:28:29 +00:00
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and Digia. For licensing terms and
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** conditions see http://qt.digia.com/licensing. For further information
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** use the contact form at http://qt.digia.com/contact-us.
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**
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2011-04-27 10:05:43 +00:00
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** GNU Lesser General Public License Usage
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2012-09-19 12:28:29 +00:00
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Digia gives you certain additional
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** rights. These rights are described in the Digia Qt LGPL Exception
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2011-04-27 10:05:43 +00:00
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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2011-05-24 09:34:08 +00:00
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** GNU General Public License Usage
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2012-09-19 12:28:29 +00:00
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 3.0 as published by the Free Software
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** Foundation and appearing in the file LICENSE.GPL included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU General Public License version 3.0 requirements will be
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** met: http://www.gnu.org/copyleft/gpl.html.
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2011-04-27 10:05:43 +00:00
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**
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2012-01-24 06:17:24 +00:00
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**
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2011-04-27 10:05:43 +00:00
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*
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These functions are based on:
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-------------------------------------------------------------------------------
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lookup3.c, by Bob Jenkins, May 2006, Public Domain.
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These are functions for producing 32-bit hashes for hash table lookup.
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2013-03-14 23:42:15 +00:00
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hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
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are externally useful functions. Routines to test the hash are included
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2011-04-27 10:05:43 +00:00
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if SELF_TEST is defined. You can use this free for any purpose. It's in
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the public domain. It has no warranty.
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You probably want to use hashlittle(). hashlittle() and hashbig()
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hash byte arrays. hashlittle() is is faster than hashbig() on
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little-endian machines. Intel and AMD are little-endian machines.
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On second thought, you probably want hashlittle2(), which is identical to
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2013-03-14 23:42:15 +00:00
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hashlittle() except it returns two 32-bit hashes for the price of one.
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2011-04-27 10:05:43 +00:00
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You could implement hashbig2() if you wanted but I haven't bothered here.
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If you want to find a hash of, say, exactly 7 integers, do
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a = i1; b = i2; c = i3;
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mix(a,b,c);
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a += i4; b += i5; c += i6;
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mix(a,b,c);
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a += i7;
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final(a,b,c);
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then use c as the hash value. If you have a variable length array of
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4-byte integers to hash, use hashword(). If you have a byte array (like
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a character string), use hashlittle(). If you have several byte arrays, or
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2013-03-14 23:42:15 +00:00
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a mix of things, see the comments above hashlittle().
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2011-04-27 10:05:43 +00:00
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2013-03-14 23:42:15 +00:00
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Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
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2011-04-27 10:05:43 +00:00
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then mix those integers. This is fast (you can do a lot more thorough
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mixing with 12*3 instructions on 3 integers than you can with 3 instructions
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on 1 byte), but shoehorning those bytes into integers efficiently is messy.
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-------------------------------------------------------------------------------
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*/
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#include <QtGlobal>
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#if Q_BYTE_ORDER == Q_BIG_ENDIAN
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# define HASH_LITTLE_ENDIAN 0
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# define HASH_BIG_ENDIAN 1
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#else
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# define HASH_LITTLE_ENDIAN 1
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# define HASH_BIG_ENDIAN 0
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#endif
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#define hashsize(n) ((quint32)1<<(n))
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#define hashmask(n) (hashsize(n)-1)
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#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
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/*
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-------------------------------------------------------------------------------
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mix -- mix 3 32-bit values reversibly.
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This is reversible, so any information in (a,b,c) before mix() is
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still in (a,b,c) after mix().
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If four pairs of (a,b,c) inputs are run through mix(), or through
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mix() in reverse, there are at least 32 bits of the output that
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are sometimes the same for one pair and different for another pair.
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This was tested for:
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* pairs that differed by one bit, by two bits, in any combination
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of top bits of (a,b,c), or in any combination of bottom bits of
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(a,b,c).
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* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
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the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
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is commonly produced by subtraction) look like a single 1-bit
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difference.
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2013-03-14 23:42:15 +00:00
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* the base values were pseudorandom, all zero but one bit set, or
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2011-04-27 10:05:43 +00:00
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all zero plus a counter that starts at zero.
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Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
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satisfy this are
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4 6 8 16 19 4
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9 15 3 18 27 15
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14 9 3 7 17 3
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Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
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for "differ" defined as + with a one-bit base and a two-bit delta. I
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2013-03-14 23:42:15 +00:00
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used http://burtleburtle.net/bob/hash/avalanche.html to choose
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2011-04-27 10:05:43 +00:00
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the operations, constants, and arrangements of the variables.
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This does not achieve avalanche. There are input bits of (a,b,c)
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that fail to affect some output bits of (a,b,c), especially of a. The
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most thoroughly mixed value is c, but it doesn't really even achieve
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avalanche in c.
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This allows some parallelism. Read-after-writes are good at doubling
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the number of bits affected, so the goal of mixing pulls in the opposite
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direction as the goal of parallelism. I did what I could. Rotates
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seem to cost as much as shifts on every machine I could lay my hands
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on, and rotates are much kinder to the top and bottom bits, so I used
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rotates.
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-------------------------------------------------------------------------------
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*/
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#define mix(a,b,c) \
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{ \
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a -= c; a ^= rot(c, 4); c += b; \
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b -= a; b ^= rot(a, 6); a += c; \
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c -= b; c ^= rot(b, 8); b += a; \
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a -= c; a ^= rot(c,16); c += b; \
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b -= a; b ^= rot(a,19); a += c; \
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c -= b; c ^= rot(b, 4); b += a; \
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}
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/*
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-------------------------------------------------------------------------------
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final -- final mixing of 3 32-bit values (a,b,c) into c
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Pairs of (a,b,c) values differing in only a few bits will usually
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produce values of c that look totally different. This was tested for
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* pairs that differed by one bit, by two bits, in any combination
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of top bits of (a,b,c), or in any combination of bottom bits of
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(a,b,c).
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* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
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the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
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is commonly produced by subtraction) look like a single 1-bit
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difference.
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2013-03-14 23:42:15 +00:00
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* the base values were pseudorandom, all zero but one bit set, or
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2011-04-27 10:05:43 +00:00
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all zero plus a counter that starts at zero.
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These constants passed:
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14 11 25 16 4 14 24
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12 14 25 16 4 14 24
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and these came close:
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4 8 15 26 3 22 24
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10 8 15 26 3 22 24
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11 8 15 26 3 22 24
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-------------------------------------------------------------------------------
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*/
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#define final(a,b,c) \
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{ \
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c ^= b; c -= rot(b,14); \
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a ^= c; a -= rot(c,11); \
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b ^= a; b -= rot(a,25); \
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c ^= b; c -= rot(b,16); \
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a ^= c; a -= rot(c,4); \
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b ^= a; b -= rot(a,14); \
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c ^= b; c -= rot(b,24); \
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}
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/*
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--------------------------------------------------------------------
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This works on all machines. To be useful, it requires
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-- that the key be an array of quint32's, and
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-- that the length be the number of quint32's in the key
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The function hashword() is identical to hashlittle() on little-endian
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machines, and identical to hashbig() on big-endian machines,
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except that the length has to be measured in quint32s rather than in
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bytes. hashlittle() is more complicated than hashword() only because
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hashlittle() has to dance around fitting the key bytes into registers.
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--------------------------------------------------------------------
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*/
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quint32 hashword(
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const quint32 *k, /* the key, an array of quint32 values */
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size_t length, /* the length of the key, in quint32s */
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quint32 initval) /* the previous hash, or an arbitrary value */
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{
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quint32 a,b,c;
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/* Set up the internal state */
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a = b = c = 0xdeadbeef + (((quint32)length)<<2) + initval;
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/*------------------------------------------------- handle most of the key */
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while (length > 3)
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{
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a += k[0];
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b += k[1];
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c += k[2];
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mix(a,b,c);
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length -= 3;
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k += 3;
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}
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/*------------------------------------------- handle the last 3 quint32's */
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switch(length) /* all the case statements fall through */
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2013-03-14 23:42:15 +00:00
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{
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2011-04-27 10:05:43 +00:00
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case 3 : c+=k[2];
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case 2 : b+=k[1];
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case 1 : a+=k[0];
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final(a,b,c);
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case 0: /* case 0: nothing left to add */
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break;
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}
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/*------------------------------------------------------ report the result */
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return c;
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}
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/*
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--------------------------------------------------------------------
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hashword2() -- same as hashword(), but take two seeds and return two
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32-bit values. pc and pb must both be nonnull, and *pc and *pb must
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2013-03-14 23:42:15 +00:00
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both be initialized with seeds. If you pass in (*pb)==0, the output
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2011-04-27 10:05:43 +00:00
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(*pc) will be the same as the return value from hashword().
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--------------------------------------------------------------------
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*/
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void hashword2 (
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const quint32 *k, /* the key, an array of quint32 values */
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size_t length, /* the length of the key, in quint32s */
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quint32 *pc, /* IN: seed OUT: primary hash value */
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quint32 *pb) /* IN: more seed OUT: secondary hash value */
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{
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quint32 a,b,c;
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/* Set up the internal state */
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a = b = c = 0xdeadbeef + ((quint32)(length<<2)) + *pc;
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c += *pb;
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/*------------------------------------------------- handle most of the key */
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while (length > 3)
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{
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a += k[0];
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b += k[1];
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c += k[2];
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mix(a,b,c);
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length -= 3;
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k += 3;
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}
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/*------------------------------------------- handle the last 3 quint32's */
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switch(length) /* all the case statements fall through */
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2013-03-14 23:42:15 +00:00
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{
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2011-04-27 10:05:43 +00:00
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case 3 : c+=k[2];
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case 2 : b+=k[1];
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case 1 : a+=k[0];
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final(a,b,c);
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case 0: /* case 0: nothing left to add */
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break;
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}
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/*------------------------------------------------------ report the result */
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*pc=c; *pb=b;
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}
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/*
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-------------------------------------------------------------------------------
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hashlittle() -- hash a variable-length key into a 32-bit value
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k : the key (the unaligned variable-length array of bytes)
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length : the length of the key, counting by bytes
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initval : can be any 4-byte value
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Returns a 32-bit value. Every bit of the key affects every bit of
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the return value. Two keys differing by one or two bits will have
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totally different hash values.
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The best hash table sizes are powers of 2. There is no need to do
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mod a prime (mod is sooo slow!). If you need less than 32 bits,
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use a bitmask. For example, if you need only 10 bits, do
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h = (h & hashmask(10));
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In which case, the hash table should have hashsize(10) elements.
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If you are hashing n strings (quint8 **)k, do it like this:
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for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);
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By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
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code any way you wish, private, educational, or commercial. It's free.
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Use for hash table lookup, or anything where one collision in 2^^32 is
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acceptable. Do NOT use for cryptographic purposes.
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-------------------------------------------------------------------------------
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*/
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quint32 hashlittle( const void *key, size_t length, quint32 initval)
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{
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quint32 a,b,c; /* internal state */
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union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
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/* Set up the internal state */
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a = b = c = 0xdeadbeef + ((quint32)length) + initval;
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u.ptr = key;
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if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
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const quint32 *k = (const quint32 *)key; /* read 32-bit chunks */
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/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
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while (length > 12)
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{
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a += k[0];
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b += k[1];
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c += k[2];
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mix(a,b,c);
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length -= 12;
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k += 3;
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}
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/*----------------------------- handle the last (probably partial) block */
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2013-03-14 23:42:15 +00:00
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/*
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2011-04-27 10:05:43 +00:00
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* "k[2]&0xffffff" actually reads beyond the end of the string, but
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* then masks off the part it's not allowed to read. Because the
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* string is aligned, the masked-off tail is in the same word as the
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* rest of the string. Every machine with memory protection I've seen
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* does it on word boundaries, so is OK with this. But VALGRIND will
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* still catch it and complain. The masking trick does make the hash
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* noticably faster for short strings (like English words).
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*/
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#ifndef VALGRIND
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switch(length)
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{
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case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
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case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
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case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
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case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
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case 8 : b+=k[1]; a+=k[0]; break;
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case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
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case 6 : b+=k[1]&0xffff; a+=k[0]; break;
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case 5 : b+=k[1]&0xff; a+=k[0]; break;
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case 4 : a+=k[0]; break;
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case 3 : a+=k[0]&0xffffff; break;
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case 2 : a+=k[0]&0xffff; break;
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case 1 : a+=k[0]&0xff; break;
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case 0 : return c; /* zero length strings require no mixing */
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}
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#else /* make valgrind happy */
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const quint8 *k8 = (const quint8 *)k;
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switch(length)
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{
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case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
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case 11: c+=((quint32)k8[10])<<16; /* fall through */
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case 10: c+=((quint32)k8[9])<<8; /* fall through */
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case 9 : c+=k8[8]; /* fall through */
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case 8 : b+=k[1]; a+=k[0]; break;
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case 7 : b+=((quint32)k8[6])<<16; /* fall through */
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case 6 : b+=((quint32)k8[5])<<8; /* fall through */
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case 5 : b+=k8[4]; /* fall through */
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case 4 : a+=k[0]; break;
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case 3 : a+=((quint32)k8[2])<<16; /* fall through */
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case 2 : a+=((quint32)k8[1])<<8; /* fall through */
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case 1 : a+=k8[0]; break;
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case 0 : return c;
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}
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#endif /* !valgrind */
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} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
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const quint16 *k = (const quint16 *)key; /* read 16-bit chunks */
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const quint8 *k8;
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/*--------------- all but last block: aligned reads and different mixing */
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while (length > 12)
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{
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a += k[0] + (((quint32)k[1])<<16);
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b += k[2] + (((quint32)k[3])<<16);
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c += k[4] + (((quint32)k[5])<<16);
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mix(a,b,c);
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length -= 12;
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k += 6;
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}
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/*----------------------------- handle the last (probably partial) block */
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k8 = (const quint8 *)k;
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switch(length)
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{
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case 12: c+=k[4]+(((quint32)k[5])<<16);
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b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 11: c+=((quint32)k8[10])<<16; /* fall through */
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case 10: c+=k[4];
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b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 9 : c+=k8[8]; /* fall through */
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case 8 : b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 7 : b+=((quint32)k8[6])<<16; /* fall through */
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case 6 : b+=k[2];
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 5 : b+=k8[4]; /* fall through */
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case 4 : a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 3 : a+=((quint32)k8[2])<<16; /* fall through */
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case 2 : a+=k[0];
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break;
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case 1 : a+=k8[0];
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break;
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case 0 : return c; /* zero length requires no mixing */
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}
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} else { /* need to read the key one byte at a time */
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const quint8 *k = (const quint8 *)key;
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/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
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while (length > 12)
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{
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a += k[0];
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a += ((quint32)k[1])<<8;
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a += ((quint32)k[2])<<16;
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a += ((quint32)k[3])<<24;
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b += k[4];
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b += ((quint32)k[5])<<8;
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b += ((quint32)k[6])<<16;
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b += ((quint32)k[7])<<24;
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c += k[8];
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c += ((quint32)k[9])<<8;
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c += ((quint32)k[10])<<16;
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c += ((quint32)k[11])<<24;
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mix(a,b,c);
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length -= 12;
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k += 12;
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}
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/*-------------------------------- last block: affect all 32 bits of (c) */
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switch(length) /* all the case statements fall through */
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{
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case 12: c+=((quint32)k[11])<<24;
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case 11: c+=((quint32)k[10])<<16;
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case 10: c+=((quint32)k[9])<<8;
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case 9 : c+=k[8];
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case 8 : b+=((quint32)k[7])<<24;
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case 7 : b+=((quint32)k[6])<<16;
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case 6 : b+=((quint32)k[5])<<8;
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case 5 : b+=k[4];
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case 4 : a+=((quint32)k[3])<<24;
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case 3 : a+=((quint32)k[2])<<16;
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case 2 : a+=((quint32)k[1])<<8;
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case 1 : a+=k[0];
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break;
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case 0 : return c;
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}
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}
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final(a,b,c);
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return c;
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}
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/*
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* hashlittle2: return 2 32-bit hash values
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*
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* This is identical to hashlittle(), except it returns two 32-bit hash
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* values instead of just one. This is good enough for hash table
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* lookup with 2^^64 buckets, or if you want a second hash if you're not
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* happy with the first, or if you want a probably-unique 64-bit ID for
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* the key. *pc is better mixed than *pb, so use *pc first. If you want
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* a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
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*/
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2013-03-14 23:42:15 +00:00
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void hashlittle2(
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2011-04-27 10:05:43 +00:00
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const void *key, /* the key to hash */
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size_t length, /* length of the key */
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quint32 *pc, /* IN: primary initval, OUT: primary hash */
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quint32 *pb) /* IN: secondary initval, OUT: secondary hash */
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{
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quint32 a,b,c; /* internal state */
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union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
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/* Set up the internal state */
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a = b = c = 0xdeadbeef + ((quint32)length) + *pc;
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c += *pb;
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u.ptr = key;
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if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
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const quint32 *k = (const quint32 *)key; /* read 32-bit chunks */
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/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
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while (length > 12)
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{
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a += k[0];
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b += k[1];
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c += k[2];
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mix(a,b,c);
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length -= 12;
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k += 3;
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}
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/*----------------------------- handle the last (probably partial) block */
|
2013-03-14 23:42:15 +00:00
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|
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/*
|
2011-04-27 10:05:43 +00:00
|
|
|
* "k[2]&0xffffff" actually reads beyond the end of the string, but
|
|
|
|
* then masks off the part it's not allowed to read. Because the
|
|
|
|
* string is aligned, the masked-off tail is in the same word as the
|
|
|
|
* rest of the string. Every machine with memory protection I've seen
|
|
|
|
* does it on word boundaries, so is OK with this. But VALGRIND will
|
|
|
|
* still catch it and complain. The masking trick does make the hash
|
|
|
|
* noticably faster for short strings (like English words).
|
|
|
|
*/
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|
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#ifndef VALGRIND
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switch(length)
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{
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case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
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case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
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case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
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case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
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case 8 : b+=k[1]; a+=k[0]; break;
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case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
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case 6 : b+=k[1]&0xffff; a+=k[0]; break;
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case 5 : b+=k[1]&0xff; a+=k[0]; break;
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case 4 : a+=k[0]; break;
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case 3 : a+=k[0]&0xffffff; break;
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case 2 : a+=k[0]&0xffff; break;
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case 1 : a+=k[0]&0xff; break;
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case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
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}
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#else /* make valgrind happy */
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const quint8 *k8 = (const quint8 *)k;
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switch(length)
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{
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case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
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case 11: c+=((quint32)k8[10])<<16; /* fall through */
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case 10: c+=((quint32)k8[9])<<8; /* fall through */
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case 9 : c+=k8[8]; /* fall through */
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case 8 : b+=k[1]; a+=k[0]; break;
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case 7 : b+=((quint32)k8[6])<<16; /* fall through */
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case 6 : b+=((quint32)k8[5])<<8; /* fall through */
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case 5 : b+=k8[4]; /* fall through */
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case 4 : a+=k[0]; break;
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case 3 : a+=((quint32)k8[2])<<16; /* fall through */
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case 2 : a+=((quint32)k8[1])<<8; /* fall through */
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case 1 : a+=k8[0]; break;
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case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
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}
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#endif /* !valgrind */
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} else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
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const quint16 *k = (const quint16 *)key; /* read 16-bit chunks */
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const quint8 *k8;
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/*--------------- all but last block: aligned reads and different mixing */
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while (length > 12)
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{
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a += k[0] + (((quint32)k[1])<<16);
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b += k[2] + (((quint32)k[3])<<16);
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c += k[4] + (((quint32)k[5])<<16);
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mix(a,b,c);
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length -= 12;
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k += 6;
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}
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/*----------------------------- handle the last (probably partial) block */
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k8 = (const quint8 *)k;
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switch(length)
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{
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case 12: c+=k[4]+(((quint32)k[5])<<16);
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b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 11: c+=((quint32)k8[10])<<16; /* fall through */
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case 10: c+=k[4];
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b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 9 : c+=k8[8]; /* fall through */
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case 8 : b+=k[2]+(((quint32)k[3])<<16);
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 7 : b+=((quint32)k8[6])<<16; /* fall through */
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case 6 : b+=k[2];
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a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 5 : b+=k8[4]; /* fall through */
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case 4 : a+=k[0]+(((quint32)k[1])<<16);
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break;
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case 3 : a+=((quint32)k8[2])<<16; /* fall through */
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case 2 : a+=k[0];
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break;
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case 1 : a+=k8[0];
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break;
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case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
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}
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} else { /* need to read the key one byte at a time */
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|
|
|
const quint8 *k = (const quint8 *)key;
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|
|
|
|
|
|
|
/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
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while (length > 12)
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{
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a += k[0];
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a += ((quint32)k[1])<<8;
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a += ((quint32)k[2])<<16;
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a += ((quint32)k[3])<<24;
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b += k[4];
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b += ((quint32)k[5])<<8;
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b += ((quint32)k[6])<<16;
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b += ((quint32)k[7])<<24;
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c += k[8];
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c += ((quint32)k[9])<<8;
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c += ((quint32)k[10])<<16;
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c += ((quint32)k[11])<<24;
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mix(a,b,c);
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length -= 12;
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k += 12;
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|
}
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|
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|
|
/*-------------------------------- last block: affect all 32 bits of (c) */
|
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|
|
switch(length) /* all the case statements fall through */
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|
{
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|
case 12: c+=((quint32)k[11])<<24;
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case 11: c+=((quint32)k[10])<<16;
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case 10: c+=((quint32)k[9])<<8;
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case 9 : c+=k[8];
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case 8 : b+=((quint32)k[7])<<24;
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case 7 : b+=((quint32)k[6])<<16;
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case 6 : b+=((quint32)k[5])<<8;
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case 5 : b+=k[4];
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|
case 4 : a+=((quint32)k[3])<<24;
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case 3 : a+=((quint32)k[2])<<16;
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|
|
case 2 : a+=((quint32)k[1])<<8;
|
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|
|
case 1 : a+=k[0];
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|
|
break;
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|
|
case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
|
|
|
|
}
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|
|
|
}
|
|
|
|
|
|
|
|
final(a,b,c);
|
|
|
|
*pc=c; *pb=b;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* hashbig():
|
|
|
|
* This is the same as hashword() on big-endian machines. It is different
|
|
|
|
* from hashlittle() on all machines. hashbig() takes advantage of
|
2013-03-14 23:42:15 +00:00
|
|
|
* big-endian byte ordering.
|
2011-04-27 10:05:43 +00:00
|
|
|
*/
|
|
|
|
quint32 hashbig( const void *key, size_t length, quint32 initval)
|
|
|
|
{
|
|
|
|
quint32 a,b,c;
|
|
|
|
union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */
|
|
|
|
|
|
|
|
/* Set up the internal state */
|
|
|
|
a = b = c = 0xdeadbeef + ((quint32)length) + initval;
|
|
|
|
|
|
|
|
u.ptr = key;
|
|
|
|
if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
|
|
|
|
const quint32 *k = (const quint32 *)key; /* read 32-bit chunks */
|
|
|
|
|
|
|
|
/*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
|
|
|
|
while (length > 12)
|
|
|
|
{
|
|
|
|
a += k[0];
|
|
|
|
b += k[1];
|
|
|
|
c += k[2];
|
|
|
|
mix(a,b,c);
|
|
|
|
length -= 12;
|
|
|
|
k += 3;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*----------------------------- handle the last (probably partial) block */
|
2013-03-14 23:42:15 +00:00
|
|
|
/*
|
2011-04-27 10:05:43 +00:00
|
|
|
* "k[2]<<8" actually reads beyond the end of the string, but
|
|
|
|
* then shifts out the part it's not allowed to read. Because the
|
|
|
|
* string is aligned, the illegal read is in the same word as the
|
|
|
|
* rest of the string. Every machine with memory protection I've seen
|
|
|
|
* does it on word boundaries, so is OK with this. But VALGRIND will
|
|
|
|
* still catch it and complain. The masking trick does make the hash
|
|
|
|
* noticably faster for short strings (like English words).
|
|
|
|
*/
|
|
|
|
#ifndef VALGRIND
|
|
|
|
|
|
|
|
switch(length)
|
|
|
|
{
|
|
|
|
case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
|
|
|
|
case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
|
|
|
|
case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
|
|
|
|
case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
|
|
|
|
case 8 : b+=k[1]; a+=k[0]; break;
|
|
|
|
case 7 : b+=k[1]&0xffffff00; a+=k[0]; break;
|
|
|
|
case 6 : b+=k[1]&0xffff0000; a+=k[0]; break;
|
|
|
|
case 5 : b+=k[1]&0xff000000; a+=k[0]; break;
|
|
|
|
case 4 : a+=k[0]; break;
|
|
|
|
case 3 : a+=k[0]&0xffffff00; break;
|
|
|
|
case 2 : a+=k[0]&0xffff0000; break;
|
|
|
|
case 1 : a+=k[0]&0xff000000; break;
|
|
|
|
case 0 : return c; /* zero length strings require no mixing */
|
|
|
|
}
|
|
|
|
|
|
|
|
#else /* make valgrind happy */
|
|
|
|
|
|
|
|
const quint8 *k8 = (const quint8 *)k;
|
|
|
|
switch(length) /* all the case statements fall through */
|
|
|
|
{
|
|
|
|
case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
|
|
|
|
case 11: c+=((quint32)k8[10])<<8; /* fall through */
|
|
|
|
case 10: c+=((quint32)k8[9])<<16; /* fall through */
|
|
|
|
case 9 : c+=((quint32)k8[8])<<24; /* fall through */
|
|
|
|
case 8 : b+=k[1]; a+=k[0]; break;
|
|
|
|
case 7 : b+=((quint32)k8[6])<<8; /* fall through */
|
|
|
|
case 6 : b+=((quint32)k8[5])<<16; /* fall through */
|
|
|
|
case 5 : b+=((quint32)k8[4])<<24; /* fall through */
|
|
|
|
case 4 : a+=k[0]; break;
|
|
|
|
case 3 : a+=((quint32)k8[2])<<8; /* fall through */
|
|
|
|
case 2 : a+=((quint32)k8[1])<<16; /* fall through */
|
|
|
|
case 1 : a+=((quint32)k8[0])<<24; break;
|
|
|
|
case 0 : return c;
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* !VALGRIND */
|
|
|
|
|
|
|
|
} else { /* need to read the key one byte at a time */
|
|
|
|
const quint8 *k = (const quint8 *)key;
|
|
|
|
|
|
|
|
/*--------------- all but the last block: affect some 32 bits of (a,b,c) */
|
|
|
|
while (length > 12)
|
|
|
|
{
|
|
|
|
a += ((quint32)k[0])<<24;
|
|
|
|
a += ((quint32)k[1])<<16;
|
|
|
|
a += ((quint32)k[2])<<8;
|
|
|
|
a += ((quint32)k[3]);
|
|
|
|
b += ((quint32)k[4])<<24;
|
|
|
|
b += ((quint32)k[5])<<16;
|
|
|
|
b += ((quint32)k[6])<<8;
|
|
|
|
b += ((quint32)k[7]);
|
|
|
|
c += ((quint32)k[8])<<24;
|
|
|
|
c += ((quint32)k[9])<<16;
|
|
|
|
c += ((quint32)k[10])<<8;
|
|
|
|
c += ((quint32)k[11]);
|
|
|
|
mix(a,b,c);
|
|
|
|
length -= 12;
|
|
|
|
k += 12;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*-------------------------------- last block: affect all 32 bits of (c) */
|
|
|
|
switch(length) /* all the case statements fall through */
|
|
|
|
{
|
|
|
|
case 12: c+=k[11];
|
|
|
|
case 11: c+=((quint32)k[10])<<8;
|
|
|
|
case 10: c+=((quint32)k[9])<<16;
|
|
|
|
case 9 : c+=((quint32)k[8])<<24;
|
|
|
|
case 8 : b+=k[7];
|
|
|
|
case 7 : b+=((quint32)k[6])<<8;
|
|
|
|
case 6 : b+=((quint32)k[5])<<16;
|
|
|
|
case 5 : b+=((quint32)k[4])<<24;
|
|
|
|
case 4 : a+=k[3];
|
|
|
|
case 3 : a+=((quint32)k[2])<<8;
|
|
|
|
case 2 : a+=((quint32)k[1])<<16;
|
|
|
|
case 1 : a+=((quint32)k[0])<<24;
|
|
|
|
break;
|
|
|
|
case 0 : return c;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
final(a,b,c);
|
|
|
|
return c;
|
|
|
|
}
|