Copyright (c) 2000, 2009 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, 2009 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.core.util;

import org.eclipse.jdt.core.compiler.CharOperation;

public final class SimpleWordSet {

// to avoid using Enumerations, walk the individual values skipping nulls
public char[][] words;
public int elementSize; // number of elements in the table
public int threshold;

public SimpleWordSet(int size) {
	this.elementSize = 0;
	this.threshold = size; // size represents the expected number of elements
	int extraRoom = (int) (size * 1.5f);
	if (this.threshold == extraRoom)
		extraRoom++;
	this.words = new char[extraRoom][];
}

public char[] add(char[] word) {
	int length = this.words.length;
	int index = CharOperation.hashCode(word) % length;
	char[] current;
	while ((current = this.words[index]) != null) {
		if (CharOperation.equals(current, word)) return current;
		if (++index == length) index = 0;
	}
	this.words[index] = word;

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

public boolean includes(char[] word) {
	int length = this.words.length;
	int index = CharOperation.hashCode(word) % length;
	char[] current;
	while ((current = this.words[index]) != null) {
		if (CharOperation.equals(current, word)) return true;
		if (++index == length) index = 0;
	}
	return false;
}

private void rehash() {
	SimpleWordSet newSet = new SimpleWordSet(this.elementSize * 2); // double the number of expected elements
	char[] current;
	for (int i = this.words.length; --i >= 0;)
		if ((current = this.words[i]) != null)
			newSet.add(current);

	this.words = newSet.words;
	this.elementSize = newSet.elementSize;
	this.threshold = newSet.threshold;
}
}