--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/concurrent/ConcurrentQueues/LoopHelpers.java	Tue Jul 28 13:24:52 2009 -0700
@@ -0,0 +1,129 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
+ */
+
+/**
+ * Misc utilities in JSR166 performance tests
+ */
+
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.*;
+
+class LoopHelpers {
+
+    // Some mindless computation to do between synchronizations...
+
+    /**
+     * generates 32 bit pseudo-random numbers.
+     * Adapted from http://www.snippets.org
+     */
+    public static int compute1(int x) {
+        int lo = 16807 * (x & 0xFFFF);
+        int hi = 16807 * (x >>> 16);
+        lo += (hi & 0x7FFF) << 16;
+        if ((lo & 0x80000000) != 0) {
+            lo &= 0x7fffffff;
+            ++lo;
+        }
+        lo += hi >>> 15;
+        if (lo == 0 || (lo & 0x80000000) != 0) {
+            lo &= 0x7fffffff;
+            ++lo;
+        }
+        return lo;
+    }
+
+    /**
+     *  Computes a linear congruential random number a random number
+     *  of times.
+     */
+    public static int compute2(int x) {
+        int loops = (x >>> 4) & 7;
+        while (loops-- > 0) {
+            x = (x * 2147483647) % 16807;
+        }
+        return x;
+    }
+
+    /**
+     * An actually useful random number generator, but unsynchronized.
+     * Basically same as java.util.Random.
+     */
+    public static class SimpleRandom {
+        private final static long multiplier = 0x5DEECE66DL;
+        private final static long addend = 0xBL;
+        private final static long mask = (1L << 48) - 1;
+        static final AtomicLong seq = new AtomicLong(1);
+        private long seed = System.nanoTime() + seq.getAndIncrement();
+
+        public void setSeed(long s) {
+            seed = s;
+        }
+
+        public int next() {
+            long nextseed = (seed * multiplier + addend) & mask;
+            seed = nextseed;
+            return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
+        }
+    }
+
+    public static class BarrierTimer implements Runnable {
+        public volatile long startTime;
+        public volatile long endTime;
+        public void run() {
+            long t = System.nanoTime();
+            if (startTime == 0)
+                startTime = t;
+            else
+                endTime = t;
+        }
+        public void clear() {
+            startTime = 0;
+            endTime = 0;
+        }
+        public long getTime() {
+            return endTime - startTime;
+        }
+    }
+
+    public static String rightJustify(long n) {
+        // There's probably a better way to do this...
+        String field = "         ";
+        String num = Long.toString(n);
+        if (num.length() >= field.length())
+            return num;
+        StringBuffer b = new StringBuffer(field);
+        b.replace(b.length()-num.length(), b.length(), num);
+        return b.toString();
+    }
+
+}