1 cananian 1.1.2.6 // StringPointer.java, created Sat Mar 27 17:05:09 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.Temp.Label;
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>StringPointer</code> class represents a pointer to an
11 duncan 1.1.2.1 * string constant. This pointer can be dereferenced
12 duncan 1.1.2.1 * with <code>getValue()</code>.
13 duncan 1.1.2.1 *
14 duncan 1.1.2.1 * @author Duncan Bryce <duncan@lcs.mit.edu>
15 cananian 1.2 * @version $Id: StringPointer.java,v 1.2 2002/02/25 21:06:01 cananian Exp $
16 duncan 1.1.2.1 */
17 duncan 1.1.2.1 public class StringPointer extends Pointer {
18 duncan 1.1.2.1 private StaticState ss;
19 duncan 1.1.2.2 private final Object value;
20 duncan 1.1.2.2
21 duncan 1.1.2.1 /** Class constructor. */
22 duncan 1.1.2.1 StringPointer(StaticState ss, Label base) {
23 duncan 1.1.2.1 super(new Object[] { base });
24 duncan 1.1.2.1 this.ss = ss;
25 duncan 1.1.2.2 this.value = Method.toNonNativeFormat
26 duncan 1.1.2.2 (ss.makeStringIntern
27 duncan 1.1.2.2 ((String)ss.map.decodeLabel((Label)getBase())));
28 duncan 1.1.2.1 }
29 duncan 1.1.2.1
30 duncan 1.1.2.1 /** Throws an error, as <code>StringPointer</code>s are constant. */
31 duncan 1.1.2.1 public Pointer add(long offset) {
32 duncan 1.1.2.1 throw new Error("Can't add to a String pointer");
33 duncan 1.1.2.1 }
34 duncan 1.1.2.1
35 duncan 1.1.2.1 /** Returns true if <code>obj</code> is a <code>StringPointer</code>
36 duncan 1.1.2.1 * that points to the same location as this <code>StringPointer</code>.
37 duncan 1.1.2.1 */
38 duncan 1.1.2.1 public boolean equals(Object obj) {
39 cananian 1.1.2.3 StringPointer ptr;
40 cananian 1.1.2.3 if (this==obj) return true;
41 cananian 1.1.2.3 if (null==obj) return false;
42 cananian 1.1.2.3 try { ptr = (StringPointer)obj; }
43 cananian 1.1.2.3 catch (ClassCastException ignore) { return false; }
44 cananian 1.1.2.3 return ptr.getBase()==getBase();
45 duncan 1.1.2.1 }
46 duncan 1.1.2.1
47 duncan 1.1.2.1 /** Returns a <code>Label</code> representing the base of this
48 duncan 1.1.2.1 * <code>StringPointer</code> */
49 duncan 1.1.2.1 public Object getBase() {
50 duncan 1.1.2.1 return proj(0);
51 duncan 1.1.2.1 }
52 duncan 1.1.2.1
53 duncan 1.1.2.1 /** Returns the offset of this <code>StringPointer</code>. */
54 duncan 1.1.2.1 public long getOffset() {
55 duncan 1.1.2.1 throw new Error("String pointers have no offsets");
56 duncan 1.1.2.1 }
57 duncan 1.1.2.1
58 duncan 1.1.2.1 /** Returns the value obtained by dereferencing this
59 duncan 1.1.2.1 * <code>StringPointer</code>. This value is in non-native format.
60 duncan 1.1.2.1 */
61 duncan 1.1.2.1 public Object getValue() {
62 duncan 1.1.2.2 return this.value;
63 duncan 1.1.2.1 }
64 duncan 1.1.2.1
65 duncan 1.1.2.1 /** Always returns true. */
66 duncan 1.1.2.1 public boolean isConst() { return true; }
67 duncan 1.1.2.1
68 duncan 1.1.2.1 /** Always returns false. */
69 duncan 1.1.2.1 public boolean isDerived() { return false; }
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.STRING_PTR; }
75 duncan 1.1.2.1
76 duncan 1.1.2.1 /** Throws an error, as <code>StringPointer</code>s are constant. */
77 duncan 1.1.2.1 public void updateValue(Object value) {
78 duncan 1.1.2.1 throw new Error("Can't update String pointer");
79 duncan 1.1.2.1 }
80 duncan 1.1.2.2
81 duncan 1.1.2.2 public String toString() {
82 duncan 1.1.2.2 return "StringPointer --> < " + value.toString() + " >";
83 duncan 1.1.2.2 }
84 duncan 1.1.2.1
85 duncan 1.1.2.1 }
86 duncan 1.1.2.2
87 duncan 1.1.2.2
88 duncan 1.1.2.2
89 cananian 1.2