001 // This file is part of the program FRYSK.
002 //
003 // Copyright 2006, Red Hat Inc.
004 //
005 // FRYSK is free software; you can redistribute it and/or modify it
006 // under the terms of the GNU General Public License as published by
007 // the Free Software Foundation; version 2 of the License.
008 //
009 // FRYSK is distributed in the hope that it will be useful, but
010 // WITHOUT ANY WARRANTY; without even the implied warranty of
011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 // General Public License for more details.
013 //
014 // You should have received a copy of the GNU General Public License
015 // along with FRYSK; if not, write to the Free Software Foundation,
016 // Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
017 //
018 // In addition, as a special exception, Red Hat, Inc. gives You the
019 // additional right to link the code of FRYSK with code not covered
020 // under the GNU General Public License ("Non-GPL Code") and to
021 // distribute linked combinations including the two, subject to the
022 // limitations in this paragraph. Non-GPL Code permitted under this
023 // exception must only link to the code of FRYSK through those well
024 // defined interfaces identified in the file named EXCEPTION found in
025 // the source code files (the "Approved Interfaces"). The files of
026 // Non-GPL Code may instantiate templates or use macros or inline
027 // functions from the Approved Interfaces without causing the
028 // resulting work to be covered by the GNU General Public
029 // License. Only Red Hat, Inc. may make changes or additions to the
030 // list of Approved Interfaces. You must obey the GNU General Public
031 // License in all respects for all of the FRYSK code and other code
032 // used in conjunction with FRYSK except the Non-GPL Code covered by
033 // this exception. If you modify this file, you may extend this
034 // exception to your version of the file, but you are not obligated to
035 // do so. If you do not wish to provide this exception without
036 // modification, you must delete this exception statement from your
037 // version and license this file solely under the GPL without
038 // exception.
039
040 package frysk.stack;
041
042 public class FrameIdentifier {
043 private final long functionAddress;
044 private final long cfa;
045
046 /**
047 * Create a new FrameIdentifier. Identifies a stack frame based on
048 * its canonical frame address and function starting address.
049 *
050 * @param functionAddress The address of the start of the frame
051 * @param cfa The canonical frame address of the stack frame
052 */
053 public FrameIdentifier (long functionAddress, long cfa) {
054 this.functionAddress = functionAddress;
055 this.cfa = cfa;
056 }
057
058 /**
059 * Returns true if this FrameIdentifier is inner to the parameter.
060 *
061 * @param fi The FrameIdentifier to compare to
062 * @return true If this is inner to fi
063 */
064 public boolean innerTo (FrameIdentifier fi) {
065 return this.cfa < fi.cfa;
066 }
067
068 /**
069 * Returns true if this FrameIdentifier is outer to the parameter.
070 *
071 * @param fi The FrameIdentifier to compare to
072 * @return true If this is outer to fi
073 */
074 public boolean outerTo (FrameIdentifier fi) {
075 return this.cfa > fi.cfa;
076 }
077
078 /**
079 * Compares this FrameIdentifier to the parameter and returns true if
080 * both the cfa and function address match.
081 *
082 * It is important to use the function address instead of the
083 * stack frame's current address because that address may change
084 * in the lifetime of * a stack frame, and thus this method could
085 * potentially return false if * one of the frames had been
086 * stepped and the other was not. Using the * frame start address
087 * guarantees that if two StackFrames are compared, * and they
088 * both represent the same frame on the stack, this method will *
089 * return true regardless of the state of either frame.
090 *
091 * @param fi The FrameIdentifier to compare to.
092 * @return true If the cfa and function address belonging to this
093 * FrameIdentifier match the cfa and function address in the parameter.
094 */
095 public boolean equals (Object fi) {
096 if (! (fi instanceof FrameIdentifier))
097 return false;
098
099 FrameIdentifier rhs = (FrameIdentifier) fi;
100 return (this.cfa == rhs.cfa
101 && this.functionAddress == rhs.functionAddress);
102 }
103
104 /**
105 * Returns the function address from this FrameIdentifier
106 *
107 * @return functionAddress The start address of the frame
108 * represented by this FrameIdentifier
109 */
110 public long getFunctionAddress () {
111 return this.functionAddress;
112 }
113
114 /**
115 * Returns a hashCode for this object
116 */
117 public int hashCode () {
118 return (int) (this.cfa ^ this.functionAddress);
119 }
120
121 /**
122 * Displays customized String output.
123 */
124 public String toString () {
125 StringBuffer buffer = new StringBuffer();
126 buffer.append("{");
127 buffer.append(super.toString());
128 buffer.append(",functionAddress=");
129 buffer.append(this.functionAddress);
130 buffer.append(",cfa=");
131 buffer.append(this.cfa);
132 buffer.append("}");
133
134 return buffer.toString();
135 }
136
137 }