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.pack200.Pack200Exception;
022import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
023import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
024
025/**
026 * Some bytecodes (such as (a)ldc, fldc and ildc) have single-byte references to the class pool. This class is the abstract superclass of those classes.
027 */
028public abstract class SingleByteReferenceForm extends ReferenceForm {
029
030    protected boolean widened;
031
032    /**
033     * Constructs a new instance with the specified opcode, name, operandType and rewrite.
034     *
035     * @param opcode  index corresponding to the opcode's value.
036     * @param name    String printable name of the opcode.
037     * @param rewrite Operand positions (which will later be rewritten in ByteCodes) are indicated by -1.
038     */
039    public SingleByteReferenceForm(final int opcode, final String name, final int[] rewrite) {
040        super(opcode, name, rewrite);
041    }
042
043    @Override
044    protected abstract int getOffset(OperandManager operandManager);
045
046    @Override
047    protected abstract int getPoolID();
048
049    @Override
050    public boolean nestedMustStartClassPool() {
051        return !widened;
052    }
053
054    @Override
055    protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset) throws Pack200Exception {
056        super.setNestedEntries(byteCode, operandManager, offset);
057        if (widened) {
058            byteCode.setNestedPositions(new int[][] { { 0, 2 } });
059        } else {
060            byteCode.setNestedPositions(new int[][] { { 0, 1 } });
061        }
062    }
063}