001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.harmony.unpack200.bytecode;
020
021import java.io.DataOutputStream;
022import java.io.IOException;
023import java.util.List;
024
025/**
026 * An entry in an exception table.
027 */
028public class ExceptionTableEntry {
029
030    private final int startPC;
031    private final int endPC;
032    private final int handlerPC;
033    private final CPClass catchType;
034
035    private int startPcRenumbered;
036    private int endPcRenumbered;
037    private int handlerPcRenumbered;
038    private int catchTypeIndex;
039
040    /**
041     * Constructs a new ExceptionTableEntry. Exception tables are of two kinds: either a normal one (with a Throwable as the catchType) or a finally clause
042     * (which has no catchType). In the class file, the finally clause is represented as catchType == 0.
043     *
044     * To create a finally clause with this method, pass in null for the catchType.
045     *
046     * @param startPC   int
047     * @param endPC     int
048     * @param handlerPC int
049     * @param catchType CPClass (if it's a normal catch) or null (if it's a finally clause).
050     */
051    public ExceptionTableEntry(final int startPC, final int endPC, final int handlerPC, final CPClass catchType) {
052        this.startPC = startPC;
053        this.endPC = endPC;
054        this.handlerPC = handlerPC;
055        this.catchType = catchType;
056    }
057
058    public CPClass getCatchType() {
059        return catchType;
060    }
061
062    public void renumber(final List<Integer> byteCodeOffsets) {
063        startPcRenumbered = byteCodeOffsets.get(startPC).intValue();
064        final int endPcIndex = startPC + endPC;
065        endPcRenumbered = byteCodeOffsets.get(endPcIndex).intValue();
066        final int handlerPcIndex = endPcIndex + handlerPC;
067        handlerPcRenumbered = byteCodeOffsets.get(handlerPcIndex).intValue();
068    }
069
070    public void resolve(final ClassConstantPool pool) {
071        if (catchType == null) {
072            // If the catch type is a finally clause
073            // the index is always 0.
074            catchTypeIndex = 0;
075            return;
076        }
077        catchType.resolve(pool);
078        catchTypeIndex = pool.indexOf(catchType);
079    }
080
081    public void write(final DataOutputStream dos) throws IOException {
082        dos.writeShort(startPcRenumbered);
083        dos.writeShort(endPcRenumbered);
084        dos.writeShort(handlerPcRenumbered);
085        dos.writeShort(catchTypeIndex);
086    }
087}