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1   /*
2    * Copyright (c) 2000, 2009, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.
8    *
9    * This code is distributed in the hope that it will be useful, but WITHOUT
10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12   * version 2 for more details (a copy is included in the LICENSE file that
13   * accompanied this code).
14   *
15   * You should have received a copy of the GNU General Public License version
16   * 2 along with this work; if not, write to the Free Software Foundation,
17   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18   *
19   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20   * or visit www.oracle.com if you need additional information or have any
21   * questions.
22   *
23   */
24  
25  package sun.jvm.hotspot.code;
26  
27  import java.io.*;
28  
29  import sun.jvm.hotspot.utilities.*;
30  
31  /** <P> Classes used for serializing debugging information. These
32      abstractions are introducted to provide symmetric read and write
33      operations. </P>
34  
35      <P>
36      <UL>
37      <LI> ScopeValue: describes the value of a variable/expression in a scope
38      <UL>
39      <LI> LocationValue: describes a value in a given location (in frame or register)
40      <LI> ConstantValue: describes a constant
41      </UL>
42      </UL>
43      </P> */
44  
45  public abstract class ScopeValue {
46    // Package private enumeration values (FIXME: read from target VM)
47    static final int LOCATION_CODE        = 0;
48    static final int CONSTANT_INT_CODE    = 1;
49    static final int CONSTANT_OOP_CODE    = 2;
50    static final int CONSTANT_LONG_CODE   = 3;
51    static final int CONSTANT_DOUBLE_CODE = 4;
52    static final int CONSTANT_OBJECT_CODE = 5;
53    static final int CONSTANT_OBJECT_ID_CODE = 6;
54  
55    public boolean isLocation()       { return false; }
56    public boolean isConstantInt()    { return false; }
57    public boolean isConstantDouble() { return false; }
58    public boolean isConstantLong()   { return false; }
59    public boolean isConstantOop()    { return false; }
60    public boolean isObject()         { return false; }
61  
62    public static ScopeValue readFrom(DebugInfoReadStream stream) {
63      switch (stream.readInt()) {
64      case LOCATION_CODE:
65        return new LocationValue(stream);
66      case CONSTANT_INT_CODE:
67        return new ConstantIntValue(stream);
68      case CONSTANT_OOP_CODE:
69        return new ConstantOopReadValue(stream);
70      case CONSTANT_LONG_CODE:
71        return new ConstantLongValue(stream);
72      case CONSTANT_DOUBLE_CODE:
73        return new ConstantDoubleValue(stream);
74      case CONSTANT_OBJECT_CODE:
75        return stream.readObjectValue();
76      case CONSTANT_OBJECT_ID_CODE:
77        return stream.getCachedObject();
78      default:
79        Assert.that(false, "should not reach here");
80        return null;
81      }
82    }
83  
84    public abstract void printOn(PrintStream tty);
85  }