Copyright (c) 2008, 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) 2008, 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.core.internal.registry;

import java.io.*;

This table stores file offsets for cached registry objects.
Entries are never added when this table resides in memory. Entries could be removed.
/**
 * This table stores file offsets for cached registry objects.
 * Entries are never added when this table resides in memory. Entries could be removed.
 */
public final class OffsetTable {

	private static final float GROWTH_FACTOR = 1.33f;

	private int[] valueTable;

	public OffsetTable(int size) {
		this.valueTable = new int[size];
	}

	public int get(int key) {
		if (key < valueTable.length)
			return valueTable[key];
		return Integer.MIN_VALUE; // should not happen; will be converted to exception higher in the call stack
	}

	public void removeKey(int key) {
		if (key < valueTable.length) // registry elements added in the running session will have IDs outside of the valid offset range
			valueTable[key] = Integer.MIN_VALUE;
	}

	public void put(int key, int value) {
		if (key >= valueTable.length) { // this should not happen in the expected use cases as we know the max size in advance
			int[] newTable = new int[(int) (key * GROWTH_FACTOR)];
			System.arraycopy(valueTable, 0, newTable, 0, valueTable.length);
			valueTable = newTable;
		}
		valueTable[key] = value;
	}

	public void save(DataOutputStream out) throws IOException {
		int tableSize = valueTable.length;
		out.writeInt(tableSize);
		for (int i = 0; i < tableSize; i++) {
			out.writeInt(valueTable[i]);
		}
	}

	static public OffsetTable load(DataInputStream in) throws IOException {
		int tableSize = in.readInt();
		OffsetTable result = new OffsetTable(tableSize);
		result.valueTable = new int[tableSize];
		for (int i = 0; i < tableSize; i++)
			result.valueTable[i] = in.readInt();
		return result;
	}

}