In 1.4.2 Sun introduced an interface to the Windows high performance timer

in sun.misc.Perf. If we can use that, we do.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@2750 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/media/timer/PerfTimer.java

@@ -0,0 +1,50 @@
+//
+// $Id: PerfTimer.java,v 1.1 2003/08/08 21:40:22 mdb Exp $
+
+package com.threerings.media.timer;
+
+import sun.misc.Perf;
+
+import com.threerings.media.Log;
+
+/**
+ * A timer that uses the performance clock exposed by Sun in JDK 1.4.2.
+ */
+public class PerfTimer implements MediaTimer
+{
+    public PerfTimer ()
+    {
+        _timer = Perf.getPerf();
+        _frequency = _timer.highResFrequency();
+        _startStamp = _timer.highResCounter() * 1000 / _frequency;
+        Log.info("Using high performance timer [freq=" + _frequency +
+                 ", start=" + _startStamp + "].");
+    }
+
+    // documentation inherited from interface
+    public void reset ()
+    {
+        _startStamp = _timer.highResCounter() * 1000 / _frequency;
+    }
+
+    // documentation inherited from interface
+    public long getElapsedMillis ()
+    {
+        return _timer.highResCounter() * 1000 / _frequency;
+    }
+
+    // documentation inherited from interface
+    public long getElapsedMicros ()
+    {
+        return _timer.highResCounter() * 100 / _frequency;
+    }
+
+    /** A performance timer object. */
+    protected Perf _timer;
+
+    /** The time at which this timer was last reset. */
+    protected long _startStamp;
+
+    /** The timer frequency. */
+    protected long _frequency;
+}