/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.compiler.util;

import net.sourceforge.phpdt.core.compiler.CharOperation;
import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;

public final class HashtableOfType {
	// to avoid using Enumerations, walk the individual tables skipping nulls
	public char[] keyTable[];

	public ReferenceBinding valueTable[];

	int elementSize; // number of elements in the table

	int threshold;

	public HashtableOfType() {
		this(3);
	}

	public HashtableOfType(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 char[extraRoom][];
		this.valueTable = new ReferenceBinding[extraRoom];
	}

	public boolean containsKey(char[] key) {
		int index = CharOperation.hashCode(key) % valueTable.length;
		int keyLength = key.length;
		char[] currentKey;
		while ((currentKey = keyTable[index]) != null) {
			if (currentKey.length == keyLength
					&& CharOperation.prefixEquals(currentKey, key))
				return true;
			index = (index + 1) % keyTable.length;
		}
		return false;
	}

	public ReferenceBinding get(char[] key) {
		int index = CharOperation.hashCode(key) % valueTable.length;
		int keyLength = key.length;
		char[] currentKey;
		while ((currentKey = keyTable[index]) != null) {
			if (currentKey.length == keyLength
					&& CharOperation.prefixEquals(currentKey, key))
				return valueTable[index];
			index = (index + 1) % keyTable.length;
		}
		return null;
	}

	public ReferenceBinding put(char[] key, ReferenceBinding value) {
		int index = CharOperation.hashCode(key) % valueTable.length;
		int keyLength = key.length;
		char[] currentKey;
		while ((currentKey = keyTable[index]) != null) {
			if (currentKey.length == keyLength
					&& CharOperation.prefixEquals(currentKey, key))
				return valueTable[index] = value;
			index = (index + 1) % keyTable.length;
		}
		keyTable[index] = key;
		valueTable[index] = value;

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

	private void rehash() {
		HashtableOfType newHashtable = new HashtableOfType(
				elementSize < 100 ? 100 : elementSize * 2); // double the number
															// of expected
															// elements
		char[] currentKey;
		for (int i = keyTable.length; --i >= 0;)
			if ((currentKey = keyTable[i]) != null)
				newHashtable.put(currentKey, valueTable[i]);

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

	public int size() {
		return elementSize;
	}

	public String toString() {
		String s = ""; //$NON-NLS-1$
		ReferenceBinding type;
		for (int i = 0, length = valueTable.length; i < length; i++)
			if ((type = valueTable[i]) != null)
				s += type.toString() + "\n"; //$NON-NLS-1$
		return s;
	}
}
