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.builder;

public class StringSet {

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

public StringSet(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.values = new String[extraRoom];
}

public boolean add(String value) {
	int length = this.values.length;
	int index = (value.hashCode() & 0x7FFFFFFF) % length;
	String current;
	while ((current = this.values[index]) != null) {
		if (value.equals(current)) return false; // did not add it since it already existed
		if (++index == length) index = 0;
	}
	this.values[index] = value;

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

public void clear() {
	for (int i = this.values.length; --i >= 0;)
		this.values[i] = null;
	this.elementSize = 0;
}

public boolean includes(String value) {
	int length = this.values.length;
	int index = (value.hashCode() & 0x7FFFFFFF) % length;
	String current;
	while ((current = this.values[index]) != null) {
		if (value.equals(current)) return true;
		if (++index == length) index = 0;
	}
	return false;
}

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

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

@Override
public String toString() {
	String s = ""; //$NON-NLS-1$
	String value;
	for (int i = 0, l = this.values.length; i < l; i++)
		if ((value = this.values[i]) != null)
			s += value + "\n"; //$NON-NLS-1$
	return s;
}
}