com.sangupta.jerry.ds.bitarray.BitArray Maven / Gradle / Ivy

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/**
 *
 * jerry - Common Java Functionality
 * Copyright (c) 2012-2015, Sandeep Gupta
 * 
 * http://sangupta.com/projects/jerry
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * 		http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */
 
package com.sangupta.jerry.ds.bitarray;

import java.io.Closeable;

/**
 * A contract for all implementations of bit-arrays. This provides
 * specific methods that will be needed for working with bloom filters.
 *  
 * @author sangupta
 * @since 1.7
 */
public interface BitArray extends Closeable {

	/**
	 * Get the bit at index
	 * 
	 * @param index
	 *            the index of the bit in the array
	 * 
	 * @return true if the bit is set, false otherwise
	 */
	public boolean getBit(int index);
	
	/**
	 * Set the bit at index
	 * 
	 * @param index
	 *            the index of the bit in the array
	 * 
	 * @return true if the bit was updated, false
	 *         otherwise.
	 * 
	 */
	public boolean setBit(int index);
	
	/**
	 * Clear all bits in the array.
	 * 
	 */
	public void clear();
	
	/**
	 * Clear a given bit at the index.
	 * 
	 * @param index
	 *            the index of the bit in the array
	 */
	public void clearBit(int index);
	
	/**
	 * Set the bit at index if the bit is unset.
	 * 
	 * @param index
	 *            the index of the bit in the array
	 * 
	 * @return true if the bit was updated, false
	 *         otherwise.
	 */
	public boolean setBitIfUnset(int index);

	/**
	 * Do a Boolean OR with the second {@link BitArray}.
	 * 
	 * @param bitArray
	 *            the bitArray to OR with
	 */
	public void or(BitArray bitArray);
	
	/**
	 * Do a Boolean AND with the second {@link BitArray}.
	 * 
	 * @param bitArray
	 *            the bitArray to AND with
	 */
	public void and(BitArray bitArray);
	
	/**
	 * The space used by this {@link BitArray} in number of bits.
	 * 
	 * @return the number of bits being used
	 */
	public int bitSize();
	
	/**
	 * The space used by this {@link BitArray} in number of bytes.
	 * 
	 * @return the number of bytes being used
	 */
	public int numBytes();

	/**
	 * Return the byte-array representation
	 * 
	 * @return the byte-array representation for this {@link BitArray}
	 */
	public byte[] toByteArray();

	/**
	 * Return the index of the highest bit that is currently set in this
	 * {@link BitArray}.
	 * 
	 * @return the index that is set, or -1 if none is set
	 */
	public int getHighestBitSet();
	
	/**
	 * Return the index of the lowest bit that is currently set in this
	 * {@link BitArray}.
	 * 
	 * @return the index that is set, or -1 if none is set
	 */
	public int getLowestBitSet();
	
}