StackMapAttribute.java

/*******************************************************************************
 * Copyright (c) 2000, 2009 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core.util;

import org.eclipse.jdt.core.util.ClassFormatException;
import org.eclipse.jdt.core.util.IConstantPool;
import org.eclipse.jdt.core.util.IStackMapAttribute;
import org.eclipse.jdt.core.util.IStackMapFrame;

/**
 * Default implementation of IStackMapAttribute.
 * 
 * @see IStackMapAttribute
 */
public class StackMapAttribute
		extends ClassFileAttribute
		implements IStackMapAttribute {

	private static final IStackMapFrame[] NO_FRAMES= new IStackMapFrame[0];

	private static final byte[] NO_ENTRIES= new byte[0];

	private int numberOfEntries;

	private IStackMapFrame[] frames;

	private byte[] bytes;

	/**
	 * Constructor for LineNumberAttribute.
	 * 
	 * @param classFileBytes
	 * @param constantPool
	 * @param offset
	 * @throws ClassFormatException
	 */
	public StackMapAttribute(
			byte[] classFileBytes,
			IConstantPool constantPool,
			int offset)
			throws ClassFormatException {
		super(classFileBytes, constantPool, offset);

		final int length= u2At(classFileBytes, 6, offset);
		this.numberOfEntries= length;
		if (length != 0) {
			int readOffset= 8;
			this.frames= new IStackMapFrame[length];
			for (int i= 0; i < length; i++) {
				DefaultStackMapFrame frame= new DefaultStackMapFrame(classFileBytes, constantPool, offset + readOffset);
				this.frames[i]= frame;
				readOffset+= frame.sizeInBytes();
			}
		} else {
			this.frames= NO_FRAMES;
		}
		final int byteLength= (int)u4At(classFileBytes, 2, offset);

		if (length != 0) {
			System.arraycopy(classFileBytes, offset + 6, this.bytes= new byte[byteLength], 0, byteLength);
		} else {
			this.bytes= NO_ENTRIES;
		}
	}

	public int getNumberOfEntries() {
		return this.numberOfEntries;
	}

	public IStackMapFrame[] getStackMapFrame() {
		return this.frames;
	}

	/**
	 */
	public byte[] getBytes() {
		return this.bytes;
	}
}