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Neo4j kernel is a lightweight, embedded Java database designed to store data structured as graphs rather than tables. For more information, see http://neo4j.org.

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/*
 * Copyright (c) 2002-2015 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.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 .
 */
package org.neo4j.kernel.impl.util.collection;

import java.util.Arrays;

import org.neo4j.collection.primitive.PrimitiveIntIterable;
import org.neo4j.collection.primitive.PrimitiveIntIterator;

/**
 * A basic bitset.
 *
 * Space usage: 20bytes + 1 bit per key.
 *
 * Performance:
 *  * put, remove, contains, size: O(1)
 *  * clear: O(size/64)
 *
 * Concurrency semantics:
 *  * Concurrent writes may lead to data loss.
 *  * Concurrent reads is fine
 *  * Concurrent reads during write is allowed, but bulk put/remove is not atomic.
 */
public class SimpleBitSet implements PrimitiveIntIterable
{
    private long[] data;

    public SimpleBitSet( int size )
    {
        int initialCapacity = size / 64;
        int capacity = 1;
        while (capacity < initialCapacity)
            capacity <<= 1;
        data = new long[capacity];
    }

    public boolean contains(int key)
    {
        int idx = key >>> 6;
        return data.length > idx && (data[idx] & ((1l << (key & 63)))) != 0;
    }

    public void put( int key )
    {
        int idx = key >>> 6;
        ensureCapacity(idx);
        data[idx] = data[idx] | (1l<< (key & 63));
    }

    public void put( SimpleBitSet other )
    {
        ensureCapacity( other.data.length - 1 );
        for(int i=0;i>> 6;
        if(data.length > idx)
        {
            data[idx] = data[idx] & ~(1l<< (key & 63));
        }
    }

    public void remove( SimpleBitSet other )
    {
        for(int i=0;i