1 cananian 1.1.2.6 // FieldPointer.java, created Sat Mar 27 17:05:07 1999 by duncan
2 cananian 1.1.2.5 // Copyright (C) 1998 Duncan Bryce <duncan@lcs.mit.edu>
3 cananian 1.1.2.5 // 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 1.1.2.2 import harpoon.ClassFile.HClass;
7 duncan 1.1.2.1 import harpoon.Util.Tuple;
8 duncan 1.1.2.1
9 duncan 1.1.2.1 /**
10 duncan 1.1.2.1 * The <code>FieldPointer</code> class represents a pointer to an
11 duncan 1.1.2.1 * <code>ObjectRef</code> plus some offset. This pointer can be dereferenced
12 duncan 1.1.2.1 * with <code>getValue()</code>, and the value at this location can be
13 duncan 1.1.2.1 * modified with <code>updateValue()</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: FieldPointer.java,v 1.2 2002/02/25 21:05:50 cananian Exp $
17 duncan 1.1.2.1 */
18 duncan 1.1.2.1 class FieldPointer extends Pointer {
19 duncan 1.1.2.1 private boolean isDerived;
20 duncan 1.1.2.1
21 duncan 1.1.2.1 // Private constructor used to add two FieldPointers.
22 duncan 1.1.2.1 private FieldPointer(FieldPointer base, long offset) {
23 duncan 1.1.2.1 this((ObjectRef)base.getBase(), base.getOffset() + offset, true);
24 duncan 1.1.2.1 }
25 duncan 1.1.2.1
26 duncan 1.1.2.1 // Private constructor used to clone a FieldPointer.
27 duncan 1.1.2.1 private FieldPointer(ObjectRef base, long offset, boolean isDerived) {
28 duncan 1.1.2.1 super(new Object[] { base, new Long(offset) });
29 duncan 1.1.2.1 this.isDerived = isDerived;
30 duncan 1.1.2.1 }
31 duncan 1.1.2.1
32 duncan 1.1.2.1 /** Class constructor. */
33 duncan 1.1.2.1 FieldPointer(ObjectRef base, long offset) {
34 duncan 1.1.2.1 this(base, offset, false);
35 duncan 1.1.2.1 }
36 duncan 1.1.2.1
37 duncan 1.1.2.1 /** Adds the specified parameter to this <code>ArrayPointer</code>'s
38 duncan 1.1.2.1 * offset. */
39 duncan 1.1.2.1 public Pointer add(long offset) {
40 duncan 1.1.2.1 return new FieldPointer(this, offset);
41 duncan 1.1.2.1 }
42 duncan 1.1.2.1
43 duncan 1.1.2.1 /** Returns true if <code>obj</code> is a <code>FieldPointer</code>
44 duncan 1.1.2.1 * that points to the same location as this <code>FieldPointer</code>.
45 duncan 1.1.2.1 */
46 duncan 1.1.2.1 public boolean equals(Object obj) {
47 cananian 1.1.2.3 FieldPointer ptr;
48 cananian 1.1.2.3 if (this==obj) return true;
49 cananian 1.1.2.3 if (null==obj) return false;
50 cananian 1.1.2.3 try { ptr = (FieldPointer)obj; }
51 cananian 1.1.2.3 catch (ClassCastException ignore) { return false; }
52 cananian 1.1.2.3 return (getBase()==ptr.getBase()) &&
53 cananian 1.1.2.3 (getOffset()==ptr.getOffset());
54 duncan 1.1.2.1 }
55 duncan 1.1.2.1
56 duncan 1.1.2.1 /** Returns an <code>ArrayRef</code> representing the base of this
57 duncan 1.1.2.1 * <code>ArrayPointer</code>. */
58 duncan 1.1.2.1 public Object getBase() { return (ObjectRef)proj(0); }
59 duncan 1.1.2.1
60 duncan 1.1.2.1 /** Returns the offset of this <code>ArrayPointer</code> */
61 duncan 1.1.2.1 public long getOffset() { return ((Long)proj(1)).longValue(); }
62 duncan 1.1.2.1
63 duncan 1.1.2.1 /** Returns the value obtained by dereferencing this
64 duncan 1.1.2.1 * <code>FieldPointer</code>. This value is in non-native format.
65 duncan 1.1.2.1 */
66 duncan 1.1.2.1 Object getValue() {
67 duncan 1.1.2.2 //return Method.toNonNativeFormat(((ObjectRef)getBase()).get(this));
68 duncan 1.1.2.2 return Method.toNonNativeFormat(ObjectRef.get(this));
69 duncan 1.1.2.1 }
70 duncan 1.1.2.4
71 duncan 1.1.2.4 /** Returns an integer enumeration of the kind of this Pointer. The
72 duncan 1.1.2.4 enumerated values are public fields of the Pointer class.
73 duncan 1.1.2.4 */
74 duncan 1.1.2.4 public int kind() { return Pointer.FIELD_PTR; }
75 duncan 1.1.2.4
76 duncan 1.1.2.1 /** Sets the value at the memory location specified by this
77 duncan 1.1.2.1 * <code>FieldPointer</code> to the specified parameter.
78 duncan 1.1.2.1 * This value should be in non-native format.
79 duncan 1.1.2.1 */
80 duncan 1.1.2.1 void updateValue(Object value) {
81 duncan 1.1.2.1 ObjectRef objref = (ObjectRef)getBase();
82 duncan 1.1.2.2 HClass type = objref.ss.getField(this).getType();
83 cananian 1.1.2.7 if (Debug.DEBUG)
84 cananian 1.1.2.7 Debug.db("Calling FieldValue.update: " + value + ", " + type);
85 duncan 1.1.2.2 ObjectRef.update(this, Method.toNativeFormat(value, type));
86 duncan 1.1.2.1 }
87 duncan 1.1.2.1
88 duncan 1.1.2.1 /** Always returns false. */
89 duncan 1.1.2.1 public boolean isConst() { return false; }
90 duncan 1.1.2.1
91 duncan 1.1.2.1 /** Returns true if this <code>ArrayPointer</code> is derived. */
92 duncan 1.1.2.1 public boolean isDerived() { return isDerived; }
93 duncan 1.1.2.1
94 duncan 1.1.2.1 /** Returns a human-readable representation of this
95 duncan 1.1.2.1 * <code>ArrayPointer</code>
96 duncan 1.1.2.1 */
97 duncan 1.1.2.1 public String toString() {
98 duncan 1.1.2.2 StringBuffer sb = new StringBuffer("FieldPtr --> < ");
99 duncan 1.1.2.2 sb.append(((ObjectRef)getBase()).toString());
100 duncan 1.1.2.1 sb.append(" , ");
101 duncan 1.1.2.1 sb.append(getOffset());
102 duncan 1.1.2.1 sb.append(" >");
103 duncan 1.1.2.1 return sb.toString();
104 duncan 1.1.2.1 }
105 duncan 1.1.2.1 }
106 duncan 1.1.2.2
107 duncan 1.1.2.2
108 duncan 1.1.2.2
109 duncan 1.1.2.2
110 duncan 1.1.2.2
111 cananian 1.2