    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 $Id$
    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}