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LongArrayHash.java
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LongArrayHash.java
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/*
* Copyright (c) 2002-2018 "Neo4j,"
* Neo4j Sweden AB [http://neo4j.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.cypher.internal.runtime;
public class LongArrayHash
{
public static final long NOT_IN_USE = -2;
public static final int SLOT_EMPTY = 0;
public static final int VALUE_FOUND = 1;
public static final int CONTINUE_PROBING = -1;
public static int hashCode( long[] arr, int from, int numberOfElements )
{
// This way of producing a hashcode for an array of longs is the
// same used by java.util.Arrays.hashCode(long[])
int h = 1;
for ( int i = from; i < from + numberOfElements; i++ )
{
long element = arr[i];
int elementHash = (int) (element ^ (element >>> 32));
h = 31 * h + elementHash;
}
return h;
}
static boolean validValue( long[] arr, int width )
{
if ( arr.length != width )
{
throw new AssertionError( "all elements in the set must have the same size" );
}
for ( long l : arr )
{
if ( l == -1 || l == -2 )
{
throw new AssertionError( "magic values -1 and -2 not allowed in keys" );
}
}
return true;
}
}