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Java > Open Source Codes > com > sun > org > apache > bcel > internal > generic > IINC


1 package com.sun.org.apache.bcel.internal.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 com.sun.org.apache.bcel.internal.util.ByteSequence;
58
59 /**
60  * IINC - Increment local variable by constant
61  *
62  * @version $Id: IINC.java,v 1.1.1.1 2001/10/29 20:00:15 jvanzyl 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   public IINC(int n, int c) {
76     super(); // Default behaviour of LocalVariableInstruction causes error
77
78     this.opcode = com.sun.org.apache.bcel.internal.Constants.IINC;
79     this.length = (short)3;
80
81     setIndex(n); // May set wide as side effect
82 setIncrement(c);
83   }
84
85   /**
86    * Dump instruction as byte code to stream out.
87    * @param out Output stream
88    */
89   public void dump(DataOutputStream out) throws IOException {
90     if(wide) // Need WIDE prefix ?
91 out.writeByte(com.sun.org.apache.bcel.internal.Constants.WIDE);
92
93     out.writeByte(opcode);
94
95     if(wide) {
96       out.writeShort(n);
97       out.writeShort(c);
98     } else {
99       out.writeByte(n);
100       out.writeByte(c);
101     }
102   }
103
104   private final void setWide() {
105     if(wide = ((n > com.sun.org.apache.bcel.internal.Constants.MAX_SHORT) ||
106            (Math.abs(c) > Byte.MAX_VALUE)))
107       length = 6; // wide byte included
108 else
109       length = 3;
110   }
111
112   /**
113    * Read needed data (e.g. index) from file.
114    */
115   protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
116   {
117     this.wide = wide;
118
119     if(wide) {
120       length = 6;
121       n = bytes.readUnsignedShort();
122       c = bytes.readShort();
123     } else {
124       length = 3;
125       n = bytes.readUnsignedByte();
126       c = bytes.readByte();
127     }
128   }
129
130   /**
131    * @return mnemonic for instruction
132    */
133   public String JavaDoc toString(boolean verbose) {
134     return super.toString(verbose) + " " + c;
135   }
136
137   /**
138    * Set index of local variable.
139    */
140   public final void setIndex(int n) {
141     if(n < 0)
142       throw new ClassGenException("Negative index value: " + n);
143
144     this.n = n;
145     setWide();
146   }
147
148   /**
149    * @return increment factor
150    */
151   public final int getIncrement() { return c; }
152
153   /**
154    * Set increment factor.
155    */
156   public final void setIncrement(int c) {
157     this.c = c;
158     setWide();
159   }
160
161   /** @return int type
162    */
163   public Type getType(ConstantPoolGen cp) {
164     return Type.INT;
165   }
166
167   /**
168    * Call corresponding visitor method(s). The order is:
169    * Call visitor methods of implemented interfaces first, then
170    * call methods according to the class hierarchy in descending order,
171    * i.e., the most specific visitXXX() call comes last.
172    *
173    * @param v Visitor object
174    */
175   public void accept(Visitor v) {
176     v.visitLocalVariableInstruction(this);
177     v.visitIINC(this);
178   }
179 }
180
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