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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * 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/publicdomain/zero/1.0/ 32 */ 33 34/** 35 * Misc utilities in JSR166 performance tests 36 */ 37class LoopHelpers { 38 39 // Some mindless computation to do between synchronizations... 40 41 /** 42 * generates 32 bit pseudo-random numbers. 43 * Adapted from http://www.snippets.org 44 */ 45 public static int compute1(int x) { 46 int lo = 16807 * (x & 0xFFFF); 47 int hi = 16807 * (x >>> 16); 48 lo += (hi & 0x7FFF) << 16; 49 if ((lo & 0x80000000) != 0) { 50 lo &= 0x7fffffff; 51 ++lo; 52 } 53 lo += hi >>> 15; 54 if (lo == 0 || (lo & 0x80000000) != 0) { 55 lo &= 0x7fffffff; 56 ++lo; 57 } 58 return lo; 59 } 60 61 /** 62 * Computes a linear congruential random number a random number 63 * of times. 64 */ 65 public static int compute2(int x) { 66 int loops = (x >>> 4) & 7; 67 while (loops-- > 0) { 68 x = (x * 2147483647) % 16807; 69 } 70 return x; 71 } 72 73 public static class BarrierTimer implements Runnable { 74 public volatile long startTime; 75 public volatile long endTime; 76 public void run() { 77 long t = System.nanoTime(); 78 if (startTime == 0) 79 startTime = t; 80 else 81 endTime = t; 82 } 83 public void clear() { 84 startTime = 0; 85 endTime = 0; 86 } 87 public long getTime() { 88 return endTime - startTime; 89 } 90 } 91 92 public static String rightJustify(long n) { 93 // There's probably a better way to do this... 94 String field = " "; 95 String num = Long.toString(n); 96 if (num.length() >= field.length()) 97 return num; 98 StringBuffer b = new StringBuffer(field); 99 b.replace(b.length()-num.length(), b.length(), num); 100 return b.toString(); 101 } 102 103} 104