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Java > Open Source Codes > gov > nasa > jpf > jvm > bytecode > LOOKUPSWITCH


1 //
2 // Copyright (C) 2005 United States Government as represented by the
3 // Administrator of the National Aeronautics and Space Administration
4 // (NASA). All Rights Reserved.
5 //
6 // This software is distributed under the NASA Open Source Agreement
7 // (NOSA), version 1.3. The NOSA has been approved by the Open Source
8 // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
9 // directory tree for the complete NOSA document.
10 //
11 // THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
12 // KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
13 // LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
14 // SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
15 // A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
16 // THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
17 // DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
18 //
19 package gov.nasa.jpf.jvm.bytecode;
20
21 import gov.nasa.jpf.jvm.KernelState;
22 import gov.nasa.jpf.jvm.SystemState;
23 import gov.nasa.jpf.jvm.ThreadInfo;
24
25 import org.apache.bcel.classfile.ConstantPool;
26 import org.apache.bcel.generic.InstructionHandle;
27
28
29 /**
30  * Access jump table by key match and jump
31  * ..., key => ...
32  */
33 public class LOOKUPSWITCH extends Instruction {
34   private int target;
35   private int[] matches;
36   private int[] targets;
37
38   public void setPeer (org.apache.bcel.generic.Instruction i, ConstantPool cp) {
39     target = ((org.apache.bcel.generic.LOOKUPSWITCH) i).getTarget()
40                                                      .getPosition();
41     matches = ((org.apache.bcel.generic.LOOKUPSWITCH) i).getMatchs();
42
43     int length = matches.length;
44     targets = new int[length];
45
46     InstructionHandle[] ih = ((org.apache.bcel.generic.LOOKUPSWITCH) i).getTargets();
47
48     for (int j = 0; j < length; j++) {
49       targets[j] = ih[j].getPosition();
50     }
51   }
52
53   public Instruction execute (SystemState ss, KernelState ks, ThreadInfo th) {
54     int value = th.pop();
55
56     for (int i = 0, l = matches.length; i < l; i++) {
57       if (value == matches[i]) {
58         return th.getMethod().getInstructionAt(targets[i]);
59       }
60     }
61
62     return th.getMethod().getInstructionAt(target);
63   }
64
65   public int getByteCode () {
66     return 0xAB;
67   }
68 }
69
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