    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
    023import org.apache.commons.compress.harmony.pack200.Pack200Exception;
    024
    025/**
    026 * Abstract superclass for attributes that have some part encoded with a BCI renumbering
    027 */
    028public abstract class BCIRenumberedAttribute extends Attribute {
    029
    030    protected boolean renumbered;
    031
    032    /*
    033     * (non-Javadoc)
    034     *
    035     * @see org.apache.commons.compress.harmony.unpack200.bytecode.Attribute#hasBCIRenumbering()
    036     */
    037    @Override
    038    public boolean hasBCIRenumbering() {
    039        return true;
    040    }
    041
    042    public BCIRenumberedAttribute(final CPUTF8 attributeName) {
    043        super(attributeName);
    044    }
    045
    046    @Override
    047    protected abstract int getLength();
    048
    049    @Override
    050    protected abstract void writeBody(DataOutputStream dos) throws IOException;
    051
    052    @Override
    053    public abstract String toString();
    054
    055    protected abstract int[] getStartPCs();
    056
    057    /**
    058     * In Pack200, line number tables are BCI renumbered. This method takes the byteCodeOffsets (which is a List of
    059     * Integers specifying the offset in the byte code array of each instruction) and updates the start_pcs so that it
    060     * points to the instruction index itself, not the BCI renumbering of the instruction.
    061     *
    062     * @param byteCodeOffsets List of Integer offsets of the bytecode array
    063     * @throws Pack200Exception TODO
    064     */
    065    public void renumber(final List byteCodeOffsets) throws Pack200Exception {
    066        if (renumbered) {
    067            throw new Error("Trying to renumber a line number table that has already been renumbered");
    068        }
    069        renumbered = true;
    070        final int[] startPCs = getStartPCs();
    071        for (int index = 0; index < startPCs.length; index++) {
    072            startPCs[index] = ((Integer) byteCodeOffsets.get(startPCs[index])).intValue();
    073        }
    074    }
    075
    076}