1 cananian 1.1.2.6 // ArrayPointer.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 1.1.2.1 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>ArrayPointer</code> class represents a pointer to an
11 duncan 1.1.2.1 * <code>ArrayRef</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: ArrayPointer.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 ArrayPointer extends Pointer {
19 duncan 1.1.2.1 private boolean isDerived;
20 duncan 1.1.2.1
21 duncan 1.1.2.1 // Constructor used to add two ArrayPointers
22 duncan 1.1.2.1 private ArrayPointer(ArrayPointer base, long offset) {
23 duncan 1.1.2.1 this((ArrayRef)base.getBase(), base.getOffset() + offset, true);
24 duncan 1.1.2.1 }
25 duncan 1.1.2.1
26 duncan 1.1.2.1 // Copy constructor
27 duncan 1.1.2.1 private ArrayPointer(ArrayRef 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 */
34 duncan 1.1.2.1 ArrayPointer(ArrayRef base, long offset) {
35 duncan 1.1.2.1 this(base, offset, offset==0);
36 duncan 1.1.2.1 }
37 duncan 1.1.2.1
38 duncan 1.1.2.1 /** Adds the specified parameter to this <code>ArrayPointer</code>'s
39 duncan 1.1.2.1 * offset */
40 duncan 1.1.2.1 public Pointer add(long offset) {
41 duncan 1.1.2.1 return new ArrayPointer(this, offset);
42 duncan 1.1.2.1 }
43 duncan 1.1.2.1
44 duncan 1.1.2.1 /** Returns true if <code>obj</code> is an <code>ArrayPointer</code>
45 duncan 1.1.2.1 * which points to the same location as this <code>ArrayPointer</code>.
46 duncan 1.1.2.1 */
47 duncan 1.1.2.1 public boolean equals(Object obj) {
48 cananian 1.1.2.3 ArrayPointer ptr;
49 cananian 1.1.2.3 if (this==obj) return true;
50 cananian 1.1.2.3 if (null==obj) return false;
51 cananian 1.1.2.3 try { ptr = (ArrayPointer)obj; }
52 cananian 1.1.2.3 catch (ClassCastException e) { return false; }
53 cananian 1.1.2.3 return (getBase()==ptr.getBase()) &&
54 cananian 1.1.2.3 (getOffset()==ptr.getOffset());
55 duncan 1.1.2.1 }
56 duncan 1.1.2.1
57 duncan 1.1.2.1 /** Returns an ArrayRef representing the base of this ArrayPointer */
58 duncan 1.1.2.1 public Object getBase() { return proj(0); }
59 duncan 1.1.2.1
60 duncan 1.1.2.1 /** Returns the offset of this ArrayPointer */
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>ArrayPointer</code>. This value is in non-nataive format.
65 duncan 1.1.2.1 */
66 duncan 1.1.2.1 Object getValue() {
67 duncan 1.1.2.1 return Method.toNonNativeFormat(ArrayRef.get(this));
68 duncan 1.1.2.1 }
69 duncan 1.1.2.4
70 duncan 1.1.2.4 /** Returns an integer enumeration of the kind of this Pointer. The
71 duncan 1.1.2.4 enumerated values are public fields of the <code>Pointer</code> class.
72 duncan 1.1.2.4 */
73 duncan 1.1.2.4 public int kind() { return Pointer.ARRAY_PTR; }
74 duncan 1.1.2.4
75 duncan 1.1.2.1 /** Sets the value at the memory location specified by this
76 duncan 1.1.2.1 * <code>ArrayPointer</code> to the specified parameter.
77 duncan 1.1.2.1 * This value should be in non-native format.
78 duncan 1.1.2.1 */
79 duncan 1.1.2.1 void updateValue(Object value) {
80 duncan 1.1.2.1 HClass type = ((ArrayRef)getBase()).type.getComponentType();
81 duncan 1.1.2.1 ArrayRef.update(this, Method.toNativeFormat(value, type));
82 duncan 1.1.2.1 }
83 duncan 1.1.2.1
84 duncan 1.1.2.1 /** Always returns false. */
85 duncan 1.1.2.1 public boolean isConst() { return false; }
86 duncan 1.1.2.1
87 duncan 1.1.2.1 /** Returns true if this ArrayPointer is derived */
88 duncan 1.1.2.2 public boolean isDerived() { return isDerived; }
89 duncan 1.1.2.1
90 duncan 1.1.2.1 /** Returns a human-readable representation of this
91 duncan 1.1.2.1 * <code>ArrayPointer</code>
92 duncan 1.1.2.1 */
93 duncan 1.1.2.1 public String toString() {
94 duncan 1.1.2.1 StringBuffer sb = new StringBuffer("ArrayPtr: < ");
95 duncan 1.1.2.1 sb.append(getBase().toString());
96 duncan 1.1.2.1 sb.append(" , ");
97 duncan 1.1.2.1 sb.append(getOffset());
98 duncan 1.1.2.1 sb.append(" > ---> ");
99 duncan 1.1.2.2 //sb.append(getValue());
100 duncan 1.1.2.1 return sb.toString();
101 duncan 1.1.2.1 }
102 duncan 1.1.2.1
103 duncan 1.1.2.1 }
104 duncan 1.1.2.1
105 duncan 1.1.2.1
106 cananian 1.2