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.forms;
018
019import java.util.Objects;
020
021import org.apache.commons.compress.harmony.pack200.Pack200Exception;
022import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
023import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
024import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
025import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
026
027/**
028 * Abstract class of all ByteCodeForms which add a nested entry from the globalConstantPool.
029 */
030public abstract class ReferenceForm extends ByteCodeForm {
031
032    public ReferenceForm(final int opcode, final String name, final int[] rewrite) {
033        super(opcode, name, rewrite);
034    }
035
036    protected abstract int getPoolID();
037
038    protected abstract int getOffset(OperandManager operandManager);
039
040    protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset)
041        throws Pack200Exception {
042        final SegmentConstantPool globalPool = operandManager.globalConstantPool();
043        ClassFileEntry[] nested = null;
044        nested = new ClassFileEntry[] {globalPool.getConstantPoolEntry(getPoolID(), offset)};
045        Objects.requireNonNull(nested[0], "Null nested entries are not allowed");
046        byteCode.setNested(nested);
047        byteCode.setNestedPositions(new int[][] {{0, 2}});
048    }
049
050    /*
051     * (non-Javadoc)
052     *
053     * @see
054     * org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons.
055     * compress.harmony.unpack200.bytecode.ByteCode,
056     * org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable,
057     * org.apache.commons.compress.harmony.unpack200.Segment)
058     */
059    @Override
060    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager,
061        final int codeLength) {
062        final int offset = getOffset(operandManager);
063        try {
064            setNestedEntries(byteCode, operandManager, offset);
065        } catch (final Pack200Exception ex) {
066            throw new Error("Got a pack200 exception. What to do?");
067        }
068    }
069}