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 *
017 */
018package org.apache.bcel.generic;
019
020import java.io.DataOutputStream;
021import java.io.IOException;
022
023import org.apache.bcel.util.ByteSequence;
024
025/**
026 * IINC - Increment local variable by constant
027 *
028 * @version $Id: IINC.java 1812166 2017-10-13 23:48:11Z ggregory $
029 */
030public class IINC extends LocalVariableInstruction {
031
032    private boolean wide;
033    private int c;
034
035
036    /**
037     * Empty constructor needed for Instruction.readInstruction.
038     * Not to be used otherwise.
039     */
040    IINC() {
041    }
042
043
044    /**
045     * @param n index of local variable
046     * @param c increment factor
047     */
048    public IINC(final int n, final int c) {
049        super(); // Default behaviour of LocalVariableInstruction causes error
050        super.setOpcode(org.apache.bcel.Const.IINC);
051        super.setLength((short) 3);
052        setIndex(n); // May set wide as side effect
053        setIncrement(c);
054    }
055
056
057    /**
058     * Dump instruction as byte code to stream out.
059     * @param out Output stream
060     */
061    @Override
062    public void dump( final DataOutputStream out ) throws IOException {
063        if (wide) {
064            out.writeByte(org.apache.bcel.Const.WIDE);
065        }
066        out.writeByte(super.getOpcode());
067        if (wide) {
068            out.writeShort(super.getIndex());
069            out.writeShort(c);
070        } else {
071            out.writeByte(super.getIndex());
072            out.writeByte(c);
073        }
074    }
075
076
077    private void setWide() {
078        wide = super.getIndex() > org.apache.bcel.Const.MAX_BYTE;
079        if (c > 0) {
080            wide = wide || (c > Byte.MAX_VALUE);
081        } else {
082            wide = wide || (c < Byte.MIN_VALUE);
083        }
084        if (wide) {
085            super.setLength(6); // wide byte included
086        } else {
087            super.setLength(3);
088        }
089    }
090
091
092    /**
093     * Read needed data (e.g. index) from file.
094     */
095    @Override
096    protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException {
097        this.wide = wide;
098        if (wide) {
099            super.setLength(6);
100            super.setIndexOnly(bytes.readUnsignedShort());
101            c = bytes.readShort();
102        } else {
103            super.setLength(3);
104            super.setIndexOnly(bytes.readUnsignedByte());
105            c = bytes.readByte();
106        }
107    }
108
109
110    /**
111     * @return mnemonic for instruction
112     */
113    @Override
114    public String toString( final boolean verbose ) {
115        return super.toString(verbose) + " " + c;
116    }
117
118
119    /**
120     * Set index of local variable.
121     */
122    @Override
123    public final void setIndex( final int n ) {
124        if (n < 0) {
125            throw new ClassGenException("Negative index value: " + n);
126        }
127        super.setIndexOnly(n);
128        setWide();
129    }
130
131
132    /**
133     * @return increment factor
134     */
135    public final int getIncrement() {
136        return c;
137    }
138
139
140    /**
141     * Set increment factor.
142     */
143    public final void setIncrement( final int c ) {
144        this.c = c;
145        setWide();
146    }
147
148
149    /** @return int type
150     */
151    @Override
152    public Type getType( final ConstantPoolGen cp ) {
153        return Type.INT;
154    }
155
156
157    /**
158     * Call corresponding visitor method(s). The order is:
159     * Call visitor methods of implemented interfaces first, then
160     * call methods according to the class hierarchy in descending order,
161     * i.e., the most specific visitXXX() call comes last.
162     *
163     * @param v Visitor object
164     */
165    @Override
166    public void accept( final Visitor v ) {
167        v.visitLocalVariableInstruction(this);
168        v.visitIINC(this);
169    }
170}