J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 3 | * |
| 4 | * This code is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License version 2 only, as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 11 | * version 2 for more details (a copy is included in the LICENSE file that |
| 12 | * accompanied this code). |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License version |
| 15 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 17 | * |
| 18 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 19 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 20 | * have any questions. |
| 21 | */ |
| 22 | |
| 23 | /* |
| 24 | * This file is available under and governed by the GNU General Public |
| 25 | * License version 2 only, as published by the Free Software Foundation. |
| 26 | * However, the following notice accompanied the original version of this |
| 27 | * file: |
| 28 | * |
| 29 | * Written by Doug Lea with assistance from members of JCP JSR-166 |
| 30 | * Expert Group and released to the public domain, as explained at |
| 31 | * http://creativecommons.org/licenses/publicdomain |
| 32 | */ |
| 33 | |
| 34 | /** |
| 35 | * Misc utilities in JSR166 performance tests |
| 36 | */ |
| 37 | |
| 38 | import java.util.concurrent.*; |
| 39 | import java.util.concurrent.atomic.*; |
| 40 | |
| 41 | class LoopHelpers { |
| 42 | |
| 43 | // Some mindless computation to do between synchronizations... |
| 44 | |
| 45 | /** |
| 46 | * generates 32 bit pseudo-random numbers. |
| 47 | * Adapted from http://www.snippets.org |
| 48 | */ |
| 49 | public static int compute1(int x) { |
| 50 | int lo = 16807 * (x & 0xFFFF); |
| 51 | int hi = 16807 * (x >>> 16); |
| 52 | lo += (hi & 0x7FFF) << 16; |
| 53 | if ((lo & 0x80000000) != 0) { |
| 54 | lo &= 0x7fffffff; |
| 55 | ++lo; |
| 56 | } |
| 57 | lo += hi >>> 15; |
| 58 | if (lo == 0 || (lo & 0x80000000) != 0) { |
| 59 | lo &= 0x7fffffff; |
| 60 | ++lo; |
| 61 | } |
| 62 | return lo; |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Computes a linear congruential random number a random number |
| 67 | * of times. |
| 68 | */ |
| 69 | public static int compute2(int x) { |
| 70 | int loops = (x >>> 4) & 7; |
| 71 | while (loops-- > 0) { |
| 72 | x = (x * 2147483647) % 16807; |
| 73 | } |
| 74 | return x; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * An actually useful random number generator, but unsynchronized. |
| 79 | * Basically same as java.util.Random. |
| 80 | */ |
| 81 | public static class SimpleRandom { |
| 82 | private final static long multiplier = 0x5DEECE66DL; |
| 83 | private final static long addend = 0xBL; |
| 84 | private final static long mask = (1L << 48) - 1; |
| 85 | static final AtomicLong seq = new AtomicLong(1); |
| 86 | private long seed = System.nanoTime() + seq.getAndIncrement(); |
| 87 | |
| 88 | public void setSeed(long s) { |
| 89 | seed = s; |
| 90 | } |
| 91 | |
| 92 | public int next() { |
| 93 | long nextseed = (seed * multiplier + addend) & mask; |
| 94 | seed = nextseed; |
| 95 | return ((int)(nextseed >>> 17)) & 0x7FFFFFFF; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | public static class BarrierTimer implements Runnable { |
| 100 | public volatile long startTime; |
| 101 | public volatile long endTime; |
| 102 | public void run() { |
| 103 | long t = System.nanoTime(); |
| 104 | if (startTime == 0) |
| 105 | startTime = t; |
| 106 | else |
| 107 | endTime = t; |
| 108 | } |
| 109 | public void clear() { |
| 110 | startTime = 0; |
| 111 | endTime = 0; |
| 112 | } |
| 113 | public long getTime() { |
| 114 | return endTime - startTime; |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | public static String rightJustify(long n) { |
| 119 | // There's probably a better way to do this... |
| 120 | String field = " "; |
| 121 | String num = Long.toString(n); |
| 122 | if (num.length() >= field.length()) |
| 123 | return num; |
| 124 | StringBuffer b = new StringBuffer(field); |
| 125 | b.replace(b.length()-num.length(), b.length(), num); |
| 126 | return b.toString(); |
| 127 | } |
| 128 | |
| 129 | } |