    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.bcel.generic;
    020
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023
    024import org.apache.bcel.classfile.Constant;
    025import org.apache.bcel.classfile.ConstantClass;
    026import org.apache.bcel.classfile.ConstantPool;
    027import org.apache.bcel.classfile.Utility;
    028import org.apache.bcel.util.ByteSequence;
    029
    030/**
    031 * Abstract super class for instructions that use an index into the constant pool such as LDC, INVOKEVIRTUAL, etc.
    032 *
    033 * @see ConstantPoolGen
    034 * @see LDC
    035 * @see INVOKEVIRTUAL
    036 */
    037public abstract class CPInstruction extends Instruction implements TypedInstruction, IndexedInstruction {
    038
    039    /**
    040     * @deprecated (since 6.0) will be made private; do not access directly, use getter/setter
    041     */
    042    @Deprecated
    043    protected int index; // index to constant pool
    044
    045    /**
    046     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    047     */
    048    CPInstruction() {
    049    }
    050
    051    /**
    052     * @param index to constant pool
    053     */
    054    protected CPInstruction(final short opcode, final int index) {
    055        super(opcode, (short) 3);
    056        setIndex(index);
    057    }
    058
    059    /**
    060     * Dump instruction as byte code to stream out.
    061     *
    062     * @param out Output stream
    063     */
    064    @Override
    065    public void dump(final DataOutputStream out) throws IOException {
    066        out.writeByte(super.getOpcode());
    067        out.writeShort(index);
    068    }
    069
    070    /**
    071     * @return index in constant pool referred by this instruction.
    072     */
    073    @Override
    074    public final int getIndex() {
    075        return index;
    076    }
    077
    078    /**
    079     * @return type related with this instruction.
    080     */
    081    @Override
    082    public Type getType(final ConstantPoolGen cpg) {
    083        final ConstantPool cp = cpg.getConstantPool();
    084        String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class);
    085        if (!name.startsWith("[")) {
    086            name = "L" + name + ";";
    087        }
    088        return Type.getType(name);
    089    }
    090
    091    /**
    092     * Reads needed data (i.e., index) from file.
    093     *
    094     * @param bytes input stream
    095     * @param wide wide prefix?
    096     */
    097    @Override
    098    protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
    099        setIndex(bytes.readUnsignedShort());
    100        super.setLength(3);
    101    }
    102
    103    /**
    104     * Sets the index to constant pool.
    105     *
    106     * @param index in constant pool.
    107     */
    108    @Override
    109    public void setIndex(final int index) { // TODO could be package-protected?
    110        if (index < 0) {
    111            throw new ClassGenException("Negative index value: " + index);
    112        }
    113        this.index = index;
    114    }
    115
    116    /**
    117     * Long output format:
    118     *
    119     * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]" "("&lt;length of instruction&gt;")" "&lt;"&lt; constant pool
    120     * index&gt;"&gt;"
    121     *
    122     * @param verbose long/short format switch
    123     * @return mnemonic for instruction
    124     */
    125    @Override
    126    public String toString(final boolean verbose) {
    127        return super.toString(verbose) + " " + index;
    128    }
    129
    130    /**
    131     * @return mnemonic for instruction with symbolic references resolved
    132     */
    133    @Override
    134    public String toString(final ConstantPool cp) {
    135        final Constant c = cp.getConstant(index);
    136        String str = cp.constantToString(c);
    137        if (c instanceof ConstantClass) {
    138            str = Utility.packageToPath(str);
    139        }
    140        return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str;
    141    }
    142}