001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one or more
003 *  contributor license agreements.  See the NOTICE file distributed with
004 *  this work for additional information regarding copyright ownership.
005 *  The ASF licenses this file to You under the Apache License, Version 2.0
006 *  (the "License"); you may not use this file except in compliance with
007 *  the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.commons.compress.harmony.unpack200.bytecode;
018
019import java.io.DataOutputStream;
020import java.io.IOException;
021import java.util.List;
022
023/**
024 * An entry in an exception table.
025 */
026public class ExceptionTableEntry {
027
028    private final int startPC;
029    private final int endPC;
030    private final int handlerPC;
031    private final CPClass catchType;
032
033    private int startPcRenumbered;
034    private int endPcRenumbered;
035    private int handlerPcRenumbered;
036    private int catchTypeIndex;
037
038    /**
039     * Constructs a new ExceptionTableEntry. Exception tables are of two kinds: either a normal one (with a Throwable as the catchType) or a finally clause
040     * (which has no catchType). In the class file, the finally clause is represented as catchType == 0.
041     *
042     * To create a finally clause with this method, pass in null for the catchType.
043     *
044     * @param startPC   int
045     * @param endPC     int
046     * @param handlerPC int
047     * @param catchType CPClass (if it's a normal catch) or null (if it's a finally clause).
048     */
049    public ExceptionTableEntry(final int startPC, final int endPC, final int handlerPC, final CPClass catchType) {
050        this.startPC = startPC;
051        this.endPC = endPC;
052        this.handlerPC = handlerPC;
053        this.catchType = catchType;
054    }
055
056    public CPClass getCatchType() {
057        return catchType;
058    }
059
060    public void renumber(final List<Integer> byteCodeOffsets) {
061        startPcRenumbered = byteCodeOffsets.get(startPC).intValue();
062        final int endPcIndex = startPC + endPC;
063        endPcRenumbered = byteCodeOffsets.get(endPcIndex).intValue();
064        final int handlerPcIndex = endPcIndex + handlerPC;
065        handlerPcRenumbered = byteCodeOffsets.get(handlerPcIndex).intValue();
066    }
067
068    public void resolve(final ClassConstantPool pool) {
069        if (catchType == null) {
070            // If the catch type is a finally clause
071            // the index is always 0.
072            catchTypeIndex = 0;
073            return;
074        }
075        catchType.resolve(pool);
076        catchTypeIndex = pool.indexOf(catchType);
077    }
078
079    public void write(final DataOutputStream dos) throws IOException {
080        dos.writeShort(startPcRenumbered);
081        dos.writeShort(endPcRenumbered);
082        dos.writeShort(handlerPcRenumbered);
083        dos.writeShort(catchTypeIndex);
084    }
085}