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Java > Open Source Codes > gov > nasa > jpf > jvm > DynamicMap


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;
20
21 import java.util.Hashtable JavaDoc;
22
23
24 /**
25  * DynamicMap is a mapping table used to achieve heap symmetry,
26  * associating thread/pc specific DynamicMapIndex objects with their
27  * corresponding DynamicArea elements[] index.
28  *
29  * If we keep it, this should really use a IntHashmap instead of a Hashtable
30  */
31 class DynamicMap {
32   static Hashtable JavaDoc mapping = new Hashtable JavaDoc();
33   static int counter = 0;
34
35   public static int getEntry (DynamicMapIndex dmi) {
36     return ((Integer JavaDoc) mapping.get(dmi)).intValue();
37   }
38
39   public static synchronized int addEntry (DynamicMapIndex dmi) {
40     int idx;
41     Integer JavaDoc index = (Integer JavaDoc) mapping.get(dmi);
42
43     if (index != null) {
44       return index.intValue();
45     }
46
47     idx = counter;
48     mapping.put(dmi.clone(), new Integer JavaDoc(idx)); // <?> pcm - dmi.clone() ?
49 counter++;
50
51     return idx;
52   }
53
54   public static boolean hasEntry (DynamicMapIndex dmi) {
55     return mapping.containsKey(dmi);
56   }
57
58   public static synchronized void init () {
59     mapping = new Hashtable JavaDoc();
60     counter = 0;
61   }
62 }
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