EncodedCatchHandler.java

/* Software Name : AsmDex
 * Version : 1.0
 *
 * Copyright © 2012 France Télécom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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package org.ow2.asmdex.structureWriter;

import java.util.ArrayList;
import java.util.List;

import org.ow2.asmdex.lowLevelUtils.ByteVector;
import org.ow2.asmdex.structureCommon.Label;

/**
 * Class representing an encoded_catch_handler. It also possibly contains encoded_type_addr_pair.
 * It is only useful when encoding the Method it is contained in, in order to allow uniqueness of this
 * structure.
 * 
 * @author Julien Névo
 */
public class EncodedCatchHandler {

	final private ConstantPool constantPool;
	
	/**
	 * Count of Catch Types in the list. Does NOT count the Catch All, and does NOT invert
	 * the sign if a Catch All is present.
	 */
	private int sizeCatchTypes = 0;
	
	/**
	 * Catch All Handler. May be Null.
	 */
	private Label catchAllHandler;
	
	/**
	 * Types of the various Handlers inside this Catch Handler. For each must corresponds
	 * an Exception Handler below.
	 */
	private List<String> types = new ArrayList<String>();
	
	/**
	 * The Excepton Handlers inside this Catch handler. For each must corresponds
	 * a Type above.
	 */
	private List<Label> exceptionHandlers = new ArrayList<Label>();

	
	/**
	 * Creates the catch handler block
	 * @param constantPool
	 */
	public EncodedCatchHandler(ConstantPool constantPool) {
		this.constantPool = constantPool;
	}
	
	
	// --------------------------------------
	// Public Methods.
	// --------------------------------------
	
	/**
	 * Add a new exception handler
	 * @param type the type of exceptions caught
	 * @param exceptionHandler label where the handler is
	 */
	public void addTypeAddrPair(String type, Label exceptionHandler) {
		if (type == null) {
			catchAllHandler = exceptionHandler;
		} else {
			types.add(type);
			exceptionHandlers.add(exceptionHandler);
			sizeCatchTypes++;
		}
	}
	
	/**
	 * Write to a byte vector  
	 * @param out where to write to
	 */
	public void write(ByteVector out) {
		// Now encodes the encoded_catch_handler item itself.
		boolean hasCatchAll = (catchAllHandler != null);
		// Encodes the number of Exception Handlers. Negative size if a CatchAll is present.
		out.putSleb128(hasCatchAll ? -sizeCatchTypes : sizeCatchTypes); // Encode size.
		
		// Encodes the encoded_type_addr_pair.
		for (int i = 0, size = types.size(); i < size; i++) {
			int typeIndex = constantPool.getTypeIndex(types.get(i));
			out.putUleb128(typeIndex);
			out.putUleb128(exceptionHandlers.get(i).getOffset() / 2);
		}
		
		// Encodes the catch_all_addr, if any.
		if (hasCatchAll) {
			out.putUleb128(catchAllHandler.getOffset() / 2);
		}
	}

	
	// --------------------------------------
	// Overridden Methods.
	// --------------------------------------
	
	@Override
	public boolean equals(Object obj) {
		if (this == obj) {
			return true;
		}

		boolean result = false;
		
		if (obj instanceof EncodedCatchHandler) {
			EncodedCatchHandler ech = (EncodedCatchHandler)obj;
			if (catchAllHandler == null) {
				result = (ech.catchAllHandler == null);
			} else {
				result = (ech.catchAllHandler == null ? false :
					catchAllHandler.equals(ech.catchAllHandler));
			}
			
			if (result) {
				result = types.equals(ech.types) && exceptionHandlers.equals(ech.exceptionHandlers);
			}
		}
		
		return result;
	}
	
	@Override
	public int hashCode() {
		int result = catchAllHandler == null ? 0 : catchAllHandler.hashCode();
		for (String type : types) {
			if (type != null) {
				result += type.hashCode();
			}
		}
		for (Label label : exceptionHandlers) {
			result += label.hashCode();
		}
		return result;
	}



}