1 cananian 1.1.2.4 // UndefinedPointer.java, created Sat Mar 27 17:05:10 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.ClassFile.HClass;
7 duncan 1.1.2.1 import harpoon.IR.Tree.NAME;
8 duncan 1.1.2.1 import harpoon.Temp.Label;
9 duncan 1.1.2.1 import harpoon.Util.Tuple;
10 duncan 1.1.2.1
11 duncan 1.1.2.1 /**
12 duncan 1.1.2.1 * The <code>UndefinedPointer</code> class represents a pointer to a
13 duncan 1.1.2.1 * value for which the type is not known. It is an error to access
14 duncan 1.1.2.1 * the value of this pointer until it is converted to a pointer of another
15 duncan 1.1.2.1 * type.
16 duncan 1.1.2.1 *
17 duncan 1.1.2.1 * @author Duncan Bryce <duncan@lcs.mit.edu>
18 cananian 1.2 * @version $Id: UndefinedPointer.java,v 1.2 2002/02/25 21:06:01 cananian Exp $
19 duncan 1.1.2.1 */
20 duncan 1.1.2.1 public class UndefinedPointer extends Pointer {
21 duncan 1.1.2.1
22 duncan 1.1.2.1 // Private constructor used to add two UndefinedPointers
23 duncan 1.1.2.1 private UndefinedPointer(UndefinedPointer ptr, long offset) {
24 duncan 1.1.2.1 this((UndefinedRef)ptr.getBase(), ptr.getOffset() + offset);
25 duncan 1.1.2.1 }
26 duncan 1.1.2.1
27 duncan 1.1.2.1 /** Class constructor */
28 duncan 1.1.2.1 public UndefinedPointer(UndefinedRef ref, long offset) {
29 duncan 1.1.2.1 super(new Object[] { ref, new Long(offset) });
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
33 duncan 1.1.2.1 * <code>UndefinedPointer</code> and returns the resulting pointer. */
34 duncan 1.1.2.1 public Pointer add(long offset) {
35 duncan 1.1.2.1 return new UndefinedPointer(this, offset);
36 duncan 1.1.2.1 }
37 duncan 1.1.2.1
38 duncan 1.1.2.1 /** Returns an <code>UndefinedRef</code> object representing the
39 duncan 1.1.2.1 * base of this <code>UndefinedPointer</code>. */
40 duncan 1.1.2.1 public Object getBase() {
41 duncan 1.1.2.1 return ((UndefinedRef)proj(0));
42 duncan 1.1.2.1 }
43 duncan 1.1.2.1
44 duncan 1.1.2.1 /** Returns the offset of this <code>UndefinedPointer</code>. */
45 duncan 1.1.2.1 public long getOffset() {
46 duncan 1.1.2.1 return ((Long)proj(1)).longValue();
47 duncan 1.1.2.1 }
48 duncan 1.1.2.1
49 duncan 1.1.2.1 /** Throws an error. */
50 duncan 1.1.2.1 Object getValue() {
51 duncan 1.1.2.1 throw new Error("Can't get value of an UndefinedPointer!");
52 duncan 1.1.2.1 }
53 duncan 1.1.2.1
54 duncan 1.1.2.1 /** Always returns false. */
55 duncan 1.1.2.1 public boolean isConst() { return false; }
56 duncan 1.1.2.1
57 duncan 1.1.2.1 /** Always returns false. */
58 duncan 1.1.2.1 public boolean isDerived() { return false; }
59 duncan 1.1.2.2
60 duncan 1.1.2.2 /** Returns an integer enumeration of the kind of this Pointer. The
61 duncan 1.1.2.2 enumerated values are public fields of the Pointer class.
62 duncan 1.1.2.2 */
63 duncan 1.1.2.2 public int kind() { return Pointer.UNDEF_PTR; }
64 duncan 1.1.2.1
65 duncan 1.1.2.1 /** Returns a human-readable representation of this
66 duncan 1.1.2.1 * <code>UndefinedPointer</code>. */
67 duncan 1.1.2.1 public String toString() {
68 duncan 1.1.2.1 StringBuffer sb = new StringBuffer("UndefPtr: < ");
69 duncan 1.1.2.1 sb.append(getOffset());
70 duncan 1.1.2.1 sb.append(" >");
71 duncan 1.1.2.1 return sb.toString();
72 duncan 1.1.2.1 }
73 duncan 1.1.2.1
74 duncan 1.1.2.1 /** Updates the value at the location pointed to by this
75 duncan 1.1.2.1 * <code>UndefinedPointer</code> to have the specified value. */
76 duncan 1.1.2.1 void updateValue(Object value) {
77 duncan 1.1.2.1 UndefinedRef.update(this, value);
78 duncan 1.1.2.1 }
79 duncan 1.1.2.1 }
80 cananian 1.2