--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/utilities/AddressOps.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2000-2002 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+package sun.jvm.hotspot.utilities;
+
+import sun.jvm.hotspot.debugger.*;
+
+/** Helper class with operations on addresses. Solves the problem of
+    one or both of the arguments being null and needing to call
+    methods like greaterThan(), lessThan(), etc. on them. */
+
+public class AddressOps {
+  /** Returns true if a1 is less than a2. Either or both may be null. */
+  public static boolean lessThan(Address a1, Address a2) {
+    if (a2 == null) {
+      return false;
+    } else if (a1 == null) {
+      return true;
+    } else {
+      return a1.lessThan(a2);
+    }
+  }
+
+  /** Returns true if a1 is less than or equal to a2. Either or both may be null. */
+  public static boolean lessThanOrEqual(Address a1, Address a2) {
+    if (a2 == null) {
+      return (a1 == null);
+    } else if (a1 == null) {
+      return true;
+    } else {
+      return a1.lessThanOrEqual(a2);
+    }
+  }
+
+  /** Returns true if a1 is greater than a2. Either or both may be null. */
+  public static boolean greaterThan(Address a1, Address a2) {
+    if (a1 == null) {
+      return false;
+    } else if (a2 == null) {
+      return true;
+    } else {
+      return a1.greaterThan(a2);
+    }
+  }
+
+  /** Returns true if a1 is greater than or equal to a2. Either or both may be null. */
+  public static boolean greaterThanOrEqual(Address a1, Address a2) {
+    if (a1 == null) {
+      return (a2 == null);
+    } else if (a2 == null) {
+      return true;
+    } else {
+      return a1.greaterThanOrEqual(a2);
+    }
+  }
+
+  /** Returns true if a1 is equal to a2. Either or both may be null. */
+  public static boolean equal(Address a1, Address a2) {
+    if ((a1 == null) && (a2 == null)) {
+      return true;
+    }
+
+    if ((a1 == null) || (a2 == null)) {
+      return false;
+    }
+
+    return (a1.equals(a2));
+  }
+
+  /** Shorthand for {@link #lessThan} */
+  public static boolean lt(Address a1, Address a2) {
+    return lessThan(a1, a2);
+  }
+
+  /** Shorthand for {@link #lessThanOrEqual} */
+  public static boolean lte(Address a1, Address a2) {
+    return lessThanOrEqual(a1, a2);
+  }
+
+  /** Shorthand for {@link #greaterThan} */
+  public static boolean gt(Address a1, Address a2) {
+    return greaterThan(a1, a2);
+  }
+
+  /** Shorthand for {@link #greaterThanOrEqual} */
+  public static boolean gte(Address a1, Address a2) {
+    return greaterThanOrEqual(a1, a2);
+  }
+
+  /** Returns maximum of the two addresses */
+  public static Address max(Address a1, Address a2) {
+    return (gt(a1, a2) ? a1 : a2);
+  }
+
+  /** Returns minimum of the two addresses */
+  public static Address min(Address a1, Address a2) {
+    return (lt(a1, a2) ? a1 : a2);
+  }
+}