Commit | Line | Data |
---|---|---|
8c8bf09f | 1 | /******************************************************************************* |
4ab33d2b | 2 | * Copyright (c) 2009 Ericsson |
8c8bf09f ASL |
3 | * |
4 | * All rights reserved. This program and the accompanying materials are | |
5 | * made available under the terms of the Eclipse Public License v1.0 which | |
6 | * accompanies this distribution, and is available at | |
7 | * http://www.eclipse.org/legal/epl-v10.html | |
8 | * | |
9 | * Contributors: | |
1f506a43 | 10 | * Francois Chouinard - Initial API and implementation |
8c8bf09f ASL |
11 | *******************************************************************************/ |
12 | ||
13 | package org.eclipse.linuxtools.tmf.event; | |
14 | ||
98029bc9 FC |
15 | import java.io.Serializable; |
16 | ||
8c8bf09f ASL |
17 | /** |
18 | * <b><u>TmfTimestamp</u></b> | |
19 | * <p> | |
20 | * The fundamental time reference in the TMF. | |
21 | * <p> | |
22 | * It provides a generic timestamp implementation in its most basic form: | |
23 | * <ul> | |
1f506a43 FC |
24 | * <li>an unstructured integer value |
25 | * <li>a time scale corresponding to the magnitude of the value wrt some | |
26 | * application-specific base unit (e.g. the second) | |
27 | * <li>a precision to indicate the error on the value (useful for comparing | |
28 | * timestamps in different scales). Default: 0. | |
8c8bf09f | 29 | * </ul> |
1f506a43 FC |
30 | * To allow synchronization of timestamps from different reference clocks, there |
31 | * is a possibility to "adjust" the timestamp both by changing its scale (traces | |
32 | * of different scale) and by adding an offset to its value (clock drift between | |
33 | * traces). | |
8c8bf09f | 34 | * <p> |
1f506a43 FC |
35 | * Note that the adjusted timestamp value could be negative e.g. for events that |
36 | * occurred before t0 of the reference clock. | |
37 | * | |
8c8bf09f | 38 | */ |
98029bc9 | 39 | public class TmfTimestamp implements Serializable { |
8c8bf09f | 40 | |
98029bc9 FC |
41 | /** |
42 | * | |
43 | */ | |
44 | private static final long serialVersionUID = -3196421507276821609L; | |
45 | ||
46 | // ======================================================================== | |
8c8bf09f | 47 | // Attributes |
4ab33d2b | 48 | // ======================================================================== |
8c8bf09f | 49 | |
1f506a43 FC |
50 | protected final long fValue; // The timestamp value |
51 | protected final byte fScale; // The time scale | |
52 | protected final long fPrecision; // The value precision (tolerance) | |
8c8bf09f | 53 | |
4ab33d2b | 54 | // ======================================================================== |
8c8bf09f | 55 | // Constants |
4ab33d2b | 56 | // ======================================================================== |
8c8bf09f ASL |
57 | |
58 | // The beginning and end of time | |
146a887c | 59 | public static final TmfTimestamp BigBang = new TmfTimestamp(Long.MIN_VALUE, Byte.MAX_VALUE, 0); |
8c8bf09f | 60 | public static final TmfTimestamp BigCrunch = new TmfTimestamp(Long.MAX_VALUE, Byte.MAX_VALUE, 0); |
8c8bf09f | 61 | |
4ab33d2b | 62 | // ======================================================================== |
8c8bf09f | 63 | // Constructors |
4ab33d2b | 64 | // ======================================================================== |
8c8bf09f ASL |
65 | |
66 | /** | |
1f506a43 | 67 | * Default constructor. |
8c8bf09f ASL |
68 | */ |
69 | public TmfTimestamp() { | |
70 | this(0, (byte) 0, 0); | |
71 | } | |
72 | ||
1f506a43 FC |
73 | /** |
74 | * Simple constructor. | |
75 | */ | |
76 | public TmfTimestamp(long value) { | |
77 | this(value, (byte) 0, 0); | |
78 | } | |
79 | ||
8c8bf09f | 80 | /** |
4ab33d2b | 81 | * Simple constructor with default error value |
8c8bf09f | 82 | * |
1f506a43 FC |
83 | * @param value |
84 | * @param scale | |
8c8bf09f ASL |
85 | */ |
86 | public TmfTimestamp(long value, byte scale) { | |
87 | this(value, scale, 0); | |
88 | } | |
89 | ||
90 | /** | |
4ab33d2b | 91 | * Constructor with measurement error. |
8c8bf09f | 92 | * |
1f506a43 FC |
93 | * @param value |
94 | * @param scale | |
95 | * @param precision | |
8c8bf09f ASL |
96 | */ |
97 | public TmfTimestamp(long value, byte scale, long precision) { | |
98 | fValue = value; | |
99 | fScale = scale; | |
100 | fPrecision = Math.abs(precision); | |
101 | } | |
102 | ||
103 | /** | |
4ab33d2b | 104 | * Copy constructor. |
8c8bf09f | 105 | * |
1f506a43 | 106 | * @param other |
8c8bf09f ASL |
107 | */ |
108 | public TmfTimestamp(TmfTimestamp other) { | |
4ab33d2b | 109 | this(other.fValue, other.fScale, other.fPrecision); |
8c8bf09f ASL |
110 | } |
111 | ||
4ab33d2b | 112 | // ======================================================================== |
8c8bf09f | 113 | // Accessors |
4ab33d2b | 114 | // ======================================================================== |
8c8bf09f ASL |
115 | |
116 | /** | |
4ab33d2b | 117 | * @return The timestamp value |
8c8bf09f ASL |
118 | */ |
119 | public long getValue() { | |
120 | return fValue; | |
121 | } | |
122 | ||
123 | /** | |
4ab33d2b | 124 | * @return The timestamp scale |
8c8bf09f ASL |
125 | */ |
126 | public byte getScale() { | |
127 | return fScale; | |
128 | } | |
129 | ||
130 | /** | |
4ab33d2b | 131 | * @return The timestamp value precision |
8c8bf09f ASL |
132 | */ |
133 | public long getPrecision() { | |
134 | return fPrecision; | |
135 | } | |
136 | ||
4ab33d2b | 137 | // ======================================================================== |
8c8bf09f | 138 | // Operators |
4ab33d2b AO |
139 | // ======================================================================== |
140 | ||
8c8bf09f ASL |
141 | /** |
142 | * Return a shifted and scaled timestamp. | |
143 | * | |
144 | * Limitation: The scaling is limited to MAX_SCALING orders of magnitude. | |
145 | * The main reason is that the 64 bits value starts to lose any significance | |
146 | * meaning beyond that scale difference and it's not even worth the trouble | |
147 | * to switch to BigDecimal arithmetics. | |
148 | * | |
1f506a43 FC |
149 | * @param offset |
150 | * - the shift value (in the same scale as newScale) | |
151 | * @param newScale | |
152 | * - the new scale | |
153 | * @return The synchronized timestamp | |
8c8bf09f | 154 | */ |
8c8bf09f | 155 | |
4ab33d2b AO |
156 | /* |
157 | * A java <code>long</code> has a maximum of 19 significant digits. | |
158 | * (-9,223,372,036,854,775,808 .. +9,223,372,036,854,775,807) | |
159 | * | |
160 | * It is therefore useless to try to synchronize 2 timestamps whose | |
161 | * difference in scale exceeds that value. | |
162 | */ | |
163 | private static int MAX_SCALING = 19; | |
1f506a43 | 164 | |
4ab33d2b AO |
165 | public TmfTimestamp synchronize(long offset, byte newScale) throws ArithmeticException { |
166 | long newValue = fValue; | |
8c8bf09f ASL |
167 | long newPrecision = fPrecision; |
168 | ||
169 | // Determine the scaling factor | |
170 | if (fScale != newScale) { | |
171 | int scaleDiff = Math.abs(fScale - newScale); | |
172 | // Let's try to be realistic... | |
173 | if (scaleDiff > MAX_SCALING) { | |
174 | throw new ArithmeticException("Scaling exception"); | |
175 | } | |
1f506a43 | 176 | // Not pretty... |
8c8bf09f | 177 | long scalingFactor = 1; |
1f506a43 | 178 | for (int i = 0; i < scaleDiff; i++) { |
8c8bf09f ASL |
179 | scalingFactor *= 10; |
180 | } | |
181 | if (newScale < fScale) { | |
182 | newValue *= scalingFactor; | |
183 | newPrecision *= scalingFactor; | |
184 | } else { | |
185 | newValue /= scalingFactor; | |
186 | newPrecision /= scalingFactor; | |
187 | } | |
188 | } | |
189 | ||
190 | return new TmfTimestamp(newValue + offset, newScale, newPrecision); | |
191 | } | |
192 | ||
193 | /** | |
194 | * Compute the adjustment, in the reference scale, needed to synchronize | |
1f506a43 | 195 | * this timestamp with a reference timestamp. |
8c8bf09f | 196 | * |
1f506a43 FC |
197 | * @param reference |
198 | * - the reference timestamp to synchronize with | |
4ab33d2b AO |
199 | * @return The adjustment term in the reference time scale |
200 | * @throws TmfNumericalException | |
8c8bf09f | 201 | */ |
4ab33d2b AO |
202 | public long getAdjustment(TmfTimestamp reference) throws ArithmeticException { |
203 | TmfTimestamp ts = synchronize(0, reference.fScale); | |
204 | return reference.fValue - ts.fValue; | |
8c8bf09f ASL |
205 | } |
206 | ||
207 | /** | |
208 | * Compare with another timestamp | |
209 | * | |
1f506a43 FC |
210 | * @param other |
211 | * - the other timestamp | |
212 | * @param withinPrecision | |
213 | * - indicates if precision is to be take into consideration | |
214 | * @return <li>-1: this timestamp is lower <li>0: timestamps are equal | |
215 | * (within precision if requested) <li>1: this timestamp is higher | |
4ab33d2b | 216 | * @throws TmfNumericalException |
8c8bf09f ASL |
217 | */ |
218 | public int compareTo(final TmfTimestamp other, boolean withinPrecision) { | |
219 | ||
62d1696a | 220 | // If values have the same time scale, perform the comparison |
8c8bf09f ASL |
221 | if (fScale == other.fScale) { |
222 | if (withinPrecision) { | |
223 | if ((fValue + fPrecision) < (other.fValue - other.fPrecision)) | |
224 | return -1; | |
225 | if ((fValue - fPrecision) > (other.fValue + other.fPrecision)) | |
226 | return 1; | |
227 | return 0; | |
228 | } | |
1f506a43 FC |
229 | return (fValue == other.fValue) ? 0 : (fValue < other.fValue) ? -1 |
230 | : 1; | |
8c8bf09f ASL |
231 | } |
232 | ||
233 | // If values have different time scales, adjust to the finest one and | |
234 | // then compare. If the scaling difference is too large, revert to | |
235 | // some heuristics. Hopefully, nobody will try to compare galactic and | |
62d1696a | 236 | // quantic clock events... |
8c8bf09f ASL |
237 | byte newScale = (fScale < other.fScale) ? fScale : other.fScale; |
238 | try { | |
239 | TmfTimestamp ts1 = this.synchronize(0, newScale); | |
240 | TmfTimestamp ts2 = other.synchronize(0, newScale); | |
241 | return ts1.compareTo(ts2, withinPrecision); | |
242 | } catch (ArithmeticException e) { | |
4ab33d2b | 243 | if ((fValue == 0) || (other.fValue == 0)) { |
1f506a43 FC |
244 | return (fValue == other.fValue) ? 0 |
245 | : (fValue < other.fValue) ? -1 : 1; | |
4ab33d2b AO |
246 | } |
247 | if ((fValue > 0) && (other.fValue > 0)) { | |
248 | return (fScale < other.fScale) ? -1 : 1; | |
249 | } | |
250 | if ((fValue < 0) && (other.fValue < 0)) { | |
251 | return (fScale > other.fScale) ? -1 : 1; | |
252 | } | |
253 | return (fValue < 0) ? -1 : 1; | |
8c8bf09f ASL |
254 | } |
255 | } | |
256 | ||
1f506a43 FC |
257 | /* |
258 | * (non-Javadoc) | |
259 | * | |
4ab33d2b AO |
260 | * @see java.lang.Object#equals(java.lang.Object) |
261 | */ | |
8c8bf09f | 262 | @Override |
8c8bf09f | 263 | public boolean equals(Object other) { |
4ab33d2b AO |
264 | if (other instanceof TmfTimestamp) |
265 | return compareTo((TmfTimestamp) other, false) == 0; | |
266 | return super.equals(other); | |
8c8bf09f ASL |
267 | } |
268 | ||
1f506a43 FC |
269 | /* (non-Javadoc) |
270 | * @see java.lang.Object#toString() | |
271 | */ | |
272 | @Override | |
273 | public String toString() { | |
274 | return "[TmfTimestamp:" + fValue + "," + fScale + "," + fPrecision + "]"; | |
275 | } | |
276 | ||
8c8bf09f | 277 | } |