1 /*
2  * Copyright (c) 2000, 2002, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.
8  *
9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  *
23  */
24 
25 package sun.jvm.hotspot.utilities;
26 
27 import sun.jvm.hotspot.debugger.*;
28 
29 /** Helper class with operations on addresses. Solves the problem of
30     one or both of the arguments being null and needing to call
31     methods like greaterThan(), lessThan(), etc. on them. */
32 
33 public class AddressOps {
34   /** Returns true if a1 is less than a2. Either or both may be null. */
lessThan(Address a1, Address a2)35   public static boolean lessThan(Address a1, Address a2) {
36     if (a2 == null) {
37       return false;
38     } else if (a1 == null) {
39       return true;
40     } else {
41       return a1.lessThan(a2);
42     }
43   }
44 
45   /** Returns true if a1 is less than or equal to a2. Either or both may be null. */
lessThanOrEqual(Address a1, Address a2)46   public static boolean lessThanOrEqual(Address a1, Address a2) {
47     if (a2 == null) {
48       return (a1 == null);
49     } else if (a1 == null) {
50       return true;
51     } else {
52       return a1.lessThanOrEqual(a2);
53     }
54   }
55 
56   /** Returns true if a1 is greater than a2. Either or both may be null. */
greaterThan(Address a1, Address a2)57   public static boolean greaterThan(Address a1, Address a2) {
58     if (a1 == null) {
59       return false;
60     } else if (a2 == null) {
61       return true;
62     } else {
63       return a1.greaterThan(a2);
64     }
65   }
66 
67   /** Returns true if a1 is greater than or equal to a2. Either or both may be null. */
greaterThanOrEqual(Address a1, Address a2)68   public static boolean greaterThanOrEqual(Address a1, Address a2) {
69     if (a1 == null) {
70       return (a2 == null);
71     } else if (a2 == null) {
72       return true;
73     } else {
74       return a1.greaterThanOrEqual(a2);
75     }
76   }
77 
78   /** Returns true if a1 is equal to a2. Either or both may be null. */
equal(Address a1, Address a2)79   public static boolean equal(Address a1, Address a2) {
80     if ((a1 == null) && (a2 == null)) {
81       return true;
82     }
83 
84     if ((a1 == null) || (a2 == null)) {
85       return false;
86     }
87 
88     return (a1.equals(a2));
89   }
90 
91   /** Shorthand for {@link #lessThan} */
lt(Address a1, Address a2)92   public static boolean lt(Address a1, Address a2) {
93     return lessThan(a1, a2);
94   }
95 
96   /** Shorthand for {@link #lessThanOrEqual} */
lte(Address a1, Address a2)97   public static boolean lte(Address a1, Address a2) {
98     return lessThanOrEqual(a1, a2);
99   }
100 
101   /** Shorthand for {@link #greaterThan} */
gt(Address a1, Address a2)102   public static boolean gt(Address a1, Address a2) {
103     return greaterThan(a1, a2);
104   }
105 
106   /** Shorthand for {@link #greaterThanOrEqual} */
gte(Address a1, Address a2)107   public static boolean gte(Address a1, Address a2) {
108     return greaterThanOrEqual(a1, a2);
109   }
110 
111   /** Returns maximum of the two addresses */
max(Address a1, Address a2)112   public static Address max(Address a1, Address a2) {
113     return (gt(a1, a2) ? a1 : a2);
114   }
115 
116   /** Returns minimum of the two addresses */
min(Address a1, Address a2)117   public static Address min(Address a1, Address a2) {
118     return (lt(a1, a2) ? a1 : a2);
119   }
120 }
121