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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