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.forms;
020
021import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
022import org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute;
023
024/**
025 * Switch instruction form.
026 */
027public abstract class SwitchForm extends VariableInstructionForm {
028
029    /**
030     * Constructs a new instance with the specified opcode, name, operandType and rewrite.
031     *
032     * @param opcode  index corresponding to the opcode's value.
033     * @param name    String printable name of the opcode.
034     */
035    public SwitchForm(final int opcode, final String name) {
036        super(opcode, name);
037    }
038
039    /*
040     * (non-Javadoc)
041     *
042     * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#fixUpByteCodeTargets(org.apache.commons
043     * .compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute)
044     */
045    @Override
046    public void fixUpByteCodeTargets(final ByteCode byteCode, final CodeAttribute codeAttribute) {
047        // SwitchForms need to fix up the target of label operations
048        final int[] originalTargets = byteCode.getByteCodeTargets();
049        final int numberOfLabels = originalTargets.length;
050        final int[] replacementTargets = new int[numberOfLabels];
051
052        final int sourceIndex = byteCode.getByteCodeIndex();
053        final int sourceValue = codeAttribute.byteCodeOffsets.get(sourceIndex).intValue();
054        for (int index = 0; index < numberOfLabels; index++) {
055            final int absoluteInstructionTargetIndex = sourceIndex + originalTargets[index];
056            final int targetValue = codeAttribute.byteCodeOffsets.get(absoluteInstructionTargetIndex).intValue();
057            replacementTargets[index] = targetValue - sourceValue;
058        }
059        final int[] rewriteArray = byteCode.getRewrite();
060        for (int index = 0; index < numberOfLabels; index++) {
061            setRewrite4Bytes(replacementTargets[index], rewriteArray);
062        }
063    }
064
065}