Copyright (c) 2000, 2008 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.util;

HashSet of Object[]
/**
 * HashSet of Object[]
 */
public final class HashSetOfInt implements Cloneable {

	// to avoid using Enumerations, walk the individual tables skipping nulls
	public int[] set;

	public int elementSize; // number of elements in the table
	int threshold;

	public HashSetOfInt() {
		this(13);
	}

	public HashSetOfInt(int size) {

		this.elementSize = 0;
		this.threshold = size; // size represents the expected number of elements
		int extraRoom = (int) (size * 1.75f);
		if (this.threshold == extraRoom)
			extraRoom++;
		this.set = new int[extraRoom];
	}

	@Override
	public Object clone() throws CloneNotSupportedException {
		HashSetOfInt result = (HashSetOfInt) super.clone();
		result.elementSize = this.elementSize;
		result.threshold = this.threshold;

		int length = this.set.length;
		result.set = new int[length];
		System.arraycopy(this.set, 0, result.set, 0, length);

		return result;
	}

	public boolean contains(int element) {
		int length = this.set.length;
		int index = element % length;
		int currentElement;
		while ((currentElement = this.set[index]) != 0) {
			if (currentElement == element)
				return true;
			if (++index == length) {
				index = 0;
			}
		}
		return false;
	}

	public int add(int element) {
		int length = this.set.length;
		int index = element % length;
		int currentElement;
		while ((currentElement = this.set[index]) != 0) {
			if (currentElement == element)
				return this.set[index] = element;
			if (++index == length) {
				index = 0;
			}
		}
		this.set[index] = element;

		// assumes the threshold is never equal to the size of the table
		if (++this.elementSize > this.threshold)
			rehash();
		return element;
	}

	public int remove(int element) {
		int length = this.set.length;
		int index = element % length;
		int currentElement;
		while ((currentElement = this.set[index]) != 0) {
			if (currentElement == element) {
				int existing = this.set[index];
				this.elementSize--;
				this.set[index] = 0;
				rehash();
				return existing;
			}
			if (++index == length) {
				index = 0;
			}
		}
		return 0;
	}

	private void rehash() {

		HashSetOfInt newHashSet = new HashSetOfInt(this.elementSize * 2);		// double the number of expected elements
		int currentElement;
		for (int i = this.set.length; --i >= 0;)
			if ((currentElement = this.set[i]) != 0)
				newHashSet.add(currentElement);

		this.set = newHashSet.set;
		this.threshold = newHashSet.threshold;
	}

	public int size() {
		return this.elementSize;
	}

	@Override
	public String toString() {
		StringBuffer buffer = new StringBuffer();
		int element;
		for (int i = 0, length = this.set.length; i < length; i++)
			if ((element = this.set[i]) != 0) {
				buffer.append(element);
				if (i != length-1)
					buffer.append('\n');
			}
		return buffer.toString();
	}
}