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.compiler.util;

Hashtable of {Object --> int }
/**
 * Hashtable of {Object --> int }
 */
public final class HashtableOfObjectToInt implements Cloneable {

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

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

	public HashtableOfObjectToInt() {
		this(13);
	}

	public HashtableOfObjectToInt(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.keyTable = new Object[extraRoom];
		this.valueTable = new int[extraRoom];
	}

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

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

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

	public boolean containsKey(Object key) {
		int length = this.keyTable.length,
			index = (key.hashCode()& 0x7FFFFFFF) % length;
		Object currentKey;
		while ((currentKey = this.keyTable[index]) != null) {
			if (currentKey.equals(key))
				return true;
			if (++index == length) {
				index = 0;
			}
		}
		return false;
	}

	public int get(Object key) {
		int length = this.keyTable.length,
			index = (key.hashCode()& 0x7FFFFFFF) % length;
		Object currentKey;
		while ((currentKey = this.keyTable[index]) != null) {
			if (currentKey.equals(key))
				return this.valueTable[index];
			if (++index == length) {
				index = 0;
			}
		}
		return -1;
	}

	public void keysToArray(Object[] array) {
		int index = 0;
		for (int i=0, length=this.keyTable.length; i<length; i++) {
			if (this.keyTable[i] != null)
				array[index++] = this.keyTable[i];
		}
	}

	public int put(Object key, int value) {
		int length = this.keyTable.length,
			index = (key.hashCode()& 0x7FFFFFFF) % length;
		Object currentKey;
		while ((currentKey = this.keyTable[index]) != null) {
			if (currentKey.equals(key))
				return this.valueTable[index] = value;
			if (++index == length) {
				index = 0;
			}
		}
		this.keyTable[index] = key;
		this.valueTable[index] = value;

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

	public int removeKey(Object key) {
		int length = this.keyTable.length,
			index = (key.hashCode()& 0x7FFFFFFF) % length;
		Object currentKey;
		while ((currentKey = this.keyTable[index]) != null) {
			if (currentKey.equals(key)) {
				int value = this.valueTable[index];
				this.elementSize--;
				this.keyTable[index] = null;
				rehash();
				return value;
			}
			if (++index == length) {
				index = 0;
			}
		}
		return -1;
	}

	private void rehash() {

		HashtableOfObjectToInt newHashtable = new HashtableOfObjectToInt(this.elementSize * 2);		// double the number of expected elements
		Object currentKey;
		for (int i = this.keyTable.length; --i >= 0;)
			if ((currentKey = this.keyTable[i]) != null)
				newHashtable.put(currentKey, this.valueTable[i]);

		this.keyTable = newHashtable.keyTable;
		this.valueTable = newHashtable.valueTable;
		this.threshold = newHashtable.threshold;
	}

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

	@Override
	public String toString() {
		String s = ""; //$NON-NLS-1$
		Object key;
		for (int i = 0, length = this.keyTable.length; i < length; i++)
			if ((key = this.keyTable[i]) != null)
				s += key + " -> " + this.valueTable[i] + "\n"; 	//$NON-NLS-2$ //$NON-NLS-1$
		return s;
	}
}