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}