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