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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   package com.sun.org.apache.bcel.internal.generic;
6   
7   /* ====================================================================
8    * The Apache Software License, Version 1.1
9    *
10   * Copyright (c) 2001 The Apache Software Foundation.  All rights
11   * reserved.
12   *
13   * Redistribution and use in source and binary forms, with or without
14   * modification, are permitted provided that the following conditions
15   * are met:
16   *
17   * 1. Redistributions of source code must retain the above copyright
18   *    notice, this list of conditions and the following disclaimer.
19   *
20   * 2. Redistributions in binary form must reproduce the above copyright
21   *    notice, this list of conditions and the following disclaimer in
22   *    the documentation and/or other materials provided with the
23   *    distribution.
24   *
25   * 3. The end-user documentation included with the redistribution,
26   *    if any, must include the following acknowledgment:
27   *       "This product includes software developed by the
28   *        Apache Software Foundation (http://www.apache.org/)."
29   *    Alternately, this acknowledgment may appear in the software itself,
30   *    if and wherever such third-party acknowledgments normally appear.
31   *
32   * 4. The names "Apache" and "Apache Software Foundation" and
33   *    "Apache BCEL" must not be used to endorse or promote products
34   *    derived from this software without prior written permission. For
35   *    written permission, please contact apache@apache.org.
36   *
37   * 5. Products derived from this software may not be called "Apache",
38   *    "Apache BCEL", nor may "Apache" appear in their name, without
39   *    prior written permission of the Apache Software Foundation.
40   *
41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52   * SUCH DAMAGE.
53   * ====================================================================
54   *
55   * This software consists of voluntary contributions made by many
56   * individuals on behalf of the Apache Software Foundation.  For more
57   * information on the Apache Software Foundation, please see
58   * <http://www.apache.org/>.
59   */
60  import java.io.*;
61  import com.sun.org.apache.bcel.internal.util.ByteSequence;
62  
63  /**
64   * IINC - Increment local variable by constant
65   *
66   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
67   */
68  public class IINC extends LocalVariableInstruction {
69    private boolean wide;
70    private int     c;
71  
72    /**
73     * Empty constructor needed for the Class.newInstance() statement in
74     * Instruction.readInstruction(). Not to be used otherwise.
75     */
76    IINC() {}
77  
78    /**
79     * @param n index of local variable
80     * @param c increment factor
81     */
82    public IINC(int n, int c) {
83      super(); // Default behaviour of LocalVariableInstruction causes error
84  
85      this.opcode = com.sun.org.apache.bcel.internal.Constants.IINC;
86      this.length = (short)3;
87  
88      setIndex(n);    // May set wide as side effect
89      setIncrement(c);
90    }
91  
92    /**
93     * Dump instruction as byte code to stream out.
94     * @param out Output stream
95     */
96    public void dump(DataOutputStream out) throws IOException {
97      if(wide) // Need WIDE prefix ?
98        out.writeByte(com.sun.org.apache.bcel.internal.Constants.WIDE);
99  
100     out.writeByte(opcode);
101 
102     if(wide) {
103       out.writeShort(n);
104       out.writeShort(c);
105     } else {
106       out.writeByte(n);
107       out.writeByte(c);
108     }
109   }
110 
111   private final void setWide() {
112     if(wide = ((n > com.sun.org.apache.bcel.internal.Constants.MAX_SHORT) ||
113                (Math.abs(c) > Byte.MAX_VALUE)))
114       length = 6; // wide byte included
115     else
116       length = 3;
117   }
118 
119   /**
120    * Read needed data (e.g. index) from file.
121    */
122   protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
123   {
124     this.wide = wide;
125 
126     if(wide) {
127       length = 6;
128       n = bytes.readUnsignedShort();
129       c = bytes.readShort();
130     } else {
131       length = 3;
132       n = bytes.readUnsignedByte();
133       c = bytes.readByte();
134     }
135   }
136 
137   /**
138    * @return mnemonic for instruction
139    */
140   public String toString(boolean verbose) {
141     return super.toString(verbose) + " " + c;
142   }
143 
144   /**
145    * Set index of local variable.
146    */
147   public final void setIndex(int n) {
148     if(n < 0)
149       throw new ClassGenException("Negative index value: " + n);
150 
151     this.n = n;
152     setWide();
153   }
154 
155   /**
156    * @return increment factor
157    */
158   public final int getIncrement() { return c; }
159 
160   /**
161    * Set increment factor.
162    */
163   public final void setIncrement(int c) {
164     this.c = c;
165     setWide();
166   }
167 
168   /** @return int type
169    */
170   public Type getType(ConstantPoolGen cp) {
171     return Type.INT;
172   }
173 
174   /**
175    * Call corresponding visitor method(s). The order is:
176    * Call visitor methods of implemented interfaces first, then
177    * call methods according to the class hierarchy in descending order,
178    * i.e., the most specific visitXXX() call comes last.
179    *
180    * @param v Visitor object
181    */
182   public void accept(Visitor v) {
183     v.visitLocalVariableInstruction(this);
184     v.visitIINC(this);
185   }
186 }