1 cananian 1.1.2.4 // Pointer.java, created Sat Mar 27 17:05:09 1999 by duncan
2 cananian 1.1.2.3 // Copyright (C) 1998 Duncan Bryce <duncan@lcs.mit.edu>
3 cananian 1.1.2.3 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 duncan 1.1.2.1 package harpoon.Interpret.Tree;
5 duncan 1.1.2.1
6 duncan 1.1.2.1 import harpoon.Util.Tuple;
7 duncan 1.1.2.1
8 duncan 1.1.2.1 /**
9 duncan 1.1.2.1 * The <code>Pointer</code> class is used to represent
10 duncan 1.1.2.1 * all pointers in the Tree interpreter. Pointers in the Tree interpreter
11 duncan 1.1.2.1 * are represented by a base, plus some optional offset. The base can
12 duncan 1.1.2.1 * be a <code>Label</code>, an <code>ArrayRef</code>, or an
13 duncan 1.1.2.1 * <code>ObjectRef</code>.
14 duncan 1.1.2.1 *
15 duncan 1.1.2.1 * @author Duncan Bryce <duncan@lcs.mit.edu>
16 cananian 1.2 * @version $Id: Pointer.java,v 1.2 2002/02/25 21:06:01 cananian Exp $
17 duncan 1.1.2.1 */
18 duncan 1.1.2.1 abstract class Pointer extends Tuple {
19 duncan 1.1.2.2 public static final int ARRAY_PTR = 0;
20 duncan 1.1.2.2 public static final int CLAZ_PTR = 1;
21 duncan 1.1.2.2 public static final int CONST_PTR = 2;
22 duncan 1.1.2.2 public static final int FIELD_PTR = 3;
23 duncan 1.1.2.2 public static final int IFACE_PTR = 4;
24 duncan 1.1.2.2 public static final int STRING_PTR = 5;
25 duncan 1.1.2.2 public static final int UNDEF_PTR = 6;
26 duncan 1.1.2.2
27 duncan 1.1.2.1
28 duncan 1.1.2.1 protected Pointer(Object[] tuple) {
29 duncan 1.1.2.1 super(tuple);
30 duncan 1.1.2.1 }
31 duncan 1.1.2.1
32 duncan 1.1.2.1 /** Adds the specified offset to the offset of this <code>Pointer</code>,
33 duncan 1.1.2.1 * and returns the new <code>Pointer</code>. */
34 duncan 1.1.2.1 abstract public Pointer add(long offset);
35 duncan 1.1.2.1
36 duncan 1.1.2.1 /** Returns the base of this <code>Pointer</code>. */
37 duncan 1.1.2.1 abstract public Object getBase();
38 duncan 1.1.2.1
39 duncan 1.1.2.1 /** Returns the offset of this <code>Pointer</code>. */
40 duncan 1.1.2.1 abstract public long getOffset();
41 duncan 1.1.2.1
42 duncan 1.1.2.1 /** Dereferences this <code>Pointer</code> and returns the resulting value.
43 duncan 1.1.2.1 */
44 duncan 1.1.2.1 abstract Object getValue();
45 duncan 1.1.2.1
46 duncan 1.1.2.1 /** Returns true if this <code>Pointer</code> is a pointer constant. */
47 duncan 1.1.2.1 abstract public boolean isConst();
48 duncan 1.1.2.1
49 duncan 1.1.2.1 /** Returns true if this <code>Pointer</code> is a derived pointer. */
50 duncan 1.1.2.1 abstract public boolean isDerived();
51 duncan 1.1.2.2
52 duncan 1.1.2.2 /** Returns an integer enumeration of the kind of this Pointer. The
53 duncan 1.1.2.2 enumerated values are public fields of the <code>Pointer</code> class.
54 duncan 1.1.2.2 */
55 duncan 1.1.2.2 abstract public int kind();
56 duncan 1.1.2.1
57 duncan 1.1.2.1 /** Updates the value at the location pointed to by this
58 duncan 1.1.2.1 * <code>Pointer</code>. */
59 duncan 1.1.2.1 abstract void updateValue(Object obj);
60 duncan 1.1.2.1 }
61 duncan 1.1.2.1
62 duncan 1.1.2.1
63 duncan 1.1.2.1
64 duncan 1.1.2.1
65 cananian 1.2