01: //
02: // Copyright (C) 2005 United States Government as represented by the
03: // Administrator of the National Aeronautics and Space Administration
04: // (NASA). All Rights Reserved.
05: //
06: // This software is distributed under the NASA Open Source Agreement
07: // (NOSA), version 1.3. The NOSA has been approved by the Open Source
08: // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
09: // 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;
20:
21: import gov.nasa.jpf.jvm.bytecode.Instruction;
22:
23: /**
24: * DynamicMapIndex instances are used to compute a deterministic object
25: * reference (i.e. index into DynamicArea elements[]) to achieve heap
26: * symmetry, so that the order of concurrent allocations does not result
27: * in different heap states (i.e. objects at the end have the same 'locations'
28: * in the heap).
29: */
30: public class DynamicMapIndex {
31: private Instruction pc;
32: private int threadref;
33: private int occurrence;
34:
35: public DynamicMapIndex(Instruction p, int t, int o) {
36: pc = p;
37: threadref = t;
38: occurrence = o;
39: }
40:
41: public Object clone() {
42: return new DynamicMapIndex(pc, threadref, occurrence);
43: }
44:
45: public boolean equals(Object obj) {
46: if (obj instanceof DynamicMapIndex) {
47: DynamicMapIndex dmi = (DynamicMapIndex) obj;
48:
49: return ((pc == dmi.pc) && (threadref == dmi.threadref) && (occurrence == dmi.occurrence));
50: }
51:
52: return false;
53: }
54:
55: public int hashCode() {
56: // <2do> pcm - that's a bit simplistic
57: return (((pc == null) ? 0 : pc.getPosition()) + threadref + occurrence);
58: }
59:
60: public void next() {
61: occurrence++;
62: }
63: }
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