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


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.ElementInfo;
22 import gov.nasa.jpf.jvm.KernelState;
23 import gov.nasa.jpf.jvm.SystemState;
24 import gov.nasa.jpf.jvm.ThreadInfo;
25
26 import org.apache.bcel.classfile.ConstantPool;
27
28
29 /**
30  * Check whether object is of given type
31  * ..., objectref => ..., objectref
32  */
33 public class CHECKCAST extends Instruction {
34   String JavaDoc type;
35
36   public void setPeer (org.apache.bcel.generic.Instruction i, ConstantPool cp) {
37     type = cp.constantToString(cp.getConstant(
38                                      ((org.apache.bcel.generic.CHECKCAST) i).getIndex()));
39
40     if (!type.startsWith("[")) {
41       type = "L" + type + ";";
42     }
43   }
44
45   public Instruction execute (SystemState ss, KernelState ks, ThreadInfo th) {
46     int objref = th.pop();
47
48     if (objref == -1) {
49       th.push(objref, true);
50     } else {
51       ElementInfo e = ks.da.get(objref);
52
53       if (e.instanceOf(type)) {
54         th.push(objref, true);
55       } else {
56         return th.createAndThrowException("java.lang.ClassCastException");
57       }
58     }
59
60     return getNext(th);
61   }
62
63   public int getByteCode () {
64     return 0xC0;
65   }
66 }
67
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