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     * @param n index of local variable
043     * @param c increment factor
044     */
045    public IINC(final int n, final int c) {
046        // Default behavior of LocalVariableInstruction causes error
047        super.setOpcode(Const.IINC);
048        super.setLength((short) 3);
049        setIndex(n); // May set wide as side effect
050        setIncrement(c);
051    }
052
053    /**
054     * Calls corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
055     * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
056     *
057     * @param v Visitor object
058     */
059    @Override
060    public void accept(final Visitor v) {
061        v.visitLocalVariableInstruction(this);
062        v.visitIINC(this);
063    }
064
065    /**
066     * Dumps instruction as byte code to stream out.
067     *
068     * @param out Output stream
069     */
070    @Override
071    public void dump(final DataOutputStream out) throws IOException {
072        if (wide) {
073            out.writeByte(Const.WIDE);
074        }
075        out.writeByte(super.getOpcode());
076        if (wide) {
077            out.writeShort(super.getIndex());
078            out.writeShort(c);
079        } else {
080            out.writeByte(super.getIndex());
081            out.writeByte(c);
082        }
083    }
084
085    /**
086     * @return increment factor
087     */
088    public final int getIncrement() {
089        return c;
090    }
091
092    /**
093     * @return int type
094     */
095    @Override
096    public Type getType(final ConstantPoolGen cp) {
097        return Type.INT;
098    }
099
100    /**
101     * Reads needed data (for example index) from file.
102     */
103    @Override
104    protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
105        this.wide = wide;
106        if (wide) {
107            super.setLength(6);
108            super.setIndexOnly(bytes.readUnsignedShort());
109            c = bytes.readShort();
110        } else {
111            super.setLength(3);
112            super.setIndexOnly(bytes.readUnsignedByte());
113            c = bytes.readByte();
114        }
115    }
116
117    /**
118     * Sets increment factor.
119     */
120    public final void setIncrement(final int c) {
121        this.c = c;
122        setWide();
123    }
124
125    /**
126     * Sets index of local variable.
127     */
128    @Override
129    public final void setIndex(final int n) {
130        if (n < 0) {
131            throw new ClassGenException("Negative index value: " + n);
132        }
133        super.setIndexOnly(n);
134        setWide();
135    }
136
137    private void setWide() {
138        wide = super.getIndex() > Const.MAX_BYTE;
139        if (c > 0) {
140            wide = wide || c > Byte.MAX_VALUE;
141        } else {
142            wide = wide || c < Byte.MIN_VALUE;
143        }
144        if (wide) {
145            super.setLength(6); // wide byte included
146        } else {
147            super.setLength(3);
148        }
149    }
150
151    /**
152     * Returns mnemonic for instruction.
153     *
154     * @return mnemonic for instruction.
155     */
156    @Override
157    public String toString(final boolean verbose) {
158        return super.toString(verbose) + " " + c;
159    }
160}