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    1   package org.apache.bcel.generic;
    2
    3   /* ====================================================================
    4    * The Apache Software License, Version 1.1
    5    *
    6    * Copyright (c) 2001 The Apache Software Foundation.  All rights
    7    * reserved.
    8    *
    9    * Redistribution and use in source and binary forms, with or without
    10   * modification, are permitted provided that the following conditions
    11   * are met:
    12   *
    13   * 1. Redistributions of source code must retain the above copyright
    14   *    notice, this list of conditions and the following disclaimer.
    15   *
    16   * 2. Redistributions in binary form must reproduce the above copyright
    17   *    notice, this list of conditions and the following disclaimer in
    18   *    the documentation and/or other materials provided with the
    19   *    distribution.
    20   *
    21   * 3. The end-user documentation included with the redistribution,
    22   *    if any, must include the following acknowledgment:
    23   *       "This product includes software developed by the
    24   *        Apache Software Foundation (http://www.apache.org/)."
    25   *    Alternately, this acknowledgment may appear in the software itself,
    26   *    if and wherever such third-party acknowledgments normally appear.
    27   *
    28   * 4. The names "Apache" and "Apache Software Foundation" and
    29   *    "Apache BCEL" must not be used to endorse or promote products
    30   *    derived from this software without prior written permission. For
    31   *    written permission, please contact apache@apache.org.
    32   *
    33   * 5. Products derived from this software may not be called "Apache",
    34   *    "Apache BCEL", nor may "Apache" appear in their name, without
    35   *    prior written permission of the Apache Software Foundation.
    36   *
    37   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    38   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    40   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
    41   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    42   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    43   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    44   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    45   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    46   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    47   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    48   * SUCH DAMAGE.
    49   * ====================================================================
    50   *
    51   * This software consists of voluntary contributions made by many
    52   * individuals on behalf of the Apache Software Foundation.  For more
    53   * information on the Apache Software Foundation, please see
    54   * <http://www.apache.org/>;.
    55   */
    56  import java.io.*;
    57  import org.apache.bcel.util.ByteSequence;
    58
    59  /***
    60   * IINC - Increment local variable by constant
    61   *
    62   * @version $Id: IINC.java,v 1.2 2002/03/12 09:24:01 mdahm Exp $
    63   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
    64   */
    65  public class IINC extends LocalVariableInstruction {
    66    private boolean wide;
    67    private int     c;
    68
    69    /***
    70     * Empty constructor needed for the Class.newInstance() statement in
    71     * Instruction.readInstruction(). Not to be used otherwise.
    72     */
    73    IINC() {}
    74
    75    /***
    76     * @param n index of local variable
    77     * @param c increment factor
    78     */
    79    public IINC(int n, int c) {
    80      super(); // Default behaviour of LocalVariableInstruction causes error
    81
    82      this.opcode = org.apache.bcel.Constants.IINC;
    83      this.length = (short)3;
    84
    85      setIndex(n);    // May set wide as side effect
    86      setIncrement(c);
    87    }
    88
    89    /***
    90     * Dump instruction as byte code to stream out.
    91     * @param out Output stream
    92     */
    93    public void dump(DataOutputStream out) throws IOException {
    94      if(wide) // Need WIDE prefix ?
    95        out.writeByte(org.apache.bcel.Constants.WIDE);
    96
    97      out.writeByte(opcode);
    98
    99      if(wide) {
    100       out.writeShort(n);
    101       out.writeShort(c);
    102     } else {
    103       out.writeByte(n);
    104       out.writeByte(c);
    105     }
    106   }
    107
    108   private final void setWide() {
    109     if(wide = ((n > org.apache.bcel.Constants.MAX_SHORT) ||
    110 	       (Math.abs(c) > Byte.MAX_VALUE)))
    111       length = 6; // wide byte included
    112     else
    113       length = 3;
    114   }
    115
    116   /***
    117    * Read needed data (e.g. index) from file.
    118    */
    119   protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
    120   {
    121     this.wide = wide;
    122
    123     if(wide) {
    124       length = 6;
    125       n = bytes.readUnsignedShort();
    126       c = bytes.readShort();
    127     } else {
    128       length = 3;
    129       n = bytes.readUnsignedByte();
    130       c = bytes.readByte();
    131     }
    132   }
    133
    134   /***
    135    * @return mnemonic for instruction
    136    */
    137   public String toString(boolean verbose) {
    138     return super.toString(verbose) + " " + c;
    139   }
    140
    141   /***
    142    * Set index of local variable.
    143    */
    144   public final void setIndex(int n) {
    145     if(n < 0)
    146       throw new ClassGenException("Negative index value: " + n);
    147
    148     this.n = n;
    149     setWide();
    150   }
    151
    152   /***
    153    * @return increment factor
    154    */
    155   public final int getIncrement() { return c; }
    156
    157   /***
    158    * Set increment factor.
    159    */
    160   public final void setIncrement(int c) {
    161     this.c = c;
    162     setWide();
    163   }
    164
    165   /*** @return int type
    166    */
    167   public Type getType(ConstantPoolGen cp) {
    168     return Type.INT;
    169   }
    170
    171   /***
    172    * Call corresponding visitor method(s). The order is:
    173    * Call visitor methods of implemented interfaces first, then
    174    * call methods according to the class hierarchy in descending order,
    175    * i.e., the most specific visitXXX() call comes last.
    176    *
    177    * @param v Visitor object
    178    */
    179   public void accept(Visitor v) {
    180     v.visitLocalVariableInstruction(this);
    181     v.visitIINC(this);
    182   }
    183 }

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