Add Clock, implementing proper monotonic and wallclock time using Instant (sec + nsec), currentTimeMillis() is also monotonic now, reused by Platform. Dropped Platform.currentTimeMicros()

Clock and its implementation was copied from jaulibs, a spin-off from Direct-BT.

The implementation uses `clock_gettime(CLOCK_MONOTONIC, &t)` and is considered safe and high-performant
as it avoids a kernel call via VDSO (GNU/Linux).

1 files changed, 6 insertions, 20 deletions

diff --git a/src/java/com/jogamp/common/os/Platform.java b/src/java/com/jogamp/common/os/Platform.java
index e6821ba..9c65596 100644
--- a/src/java/com/jogamp/common/os/Platform.java
+++ b/src/java/com/jogamp/common/os/Platform.java
@@ -1,5 +1,5 @@
 /**
- * Copyright 2010 JogAmp Community. All rights reserved.
+ * Copyright 2010-2023 JogAmp Community. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification, are
  * permitted provided that the following conditions are met:
@@ -521,26 +521,12 @@ public class Platform extends PlatformPropsImpl {
     //
 
     /**
-     * Returns the unix based current time in milliseconds, based on <code>gettimeofday(..)</code>.
-     * <p>
-     * This is an alternative to {@link System#currentTimeMillis()} and {@link System#nanoTime()}.
-     * While the named {@link System} methods do provide the required precision,
-     * <code>gettimeofday()</code> <i>also</i> guarantees time accuracy, i.e. update interval.
-     * </p>
-     * @see #currentTimeMicros()
-     */
-    public static native long currentTimeMillis();
-
-    /**
-     * Returns the unix based current time in microseconds, based on <code>gettimeofday(..)</code>.
-     * <p>
-     * This is an alternative to {@link System#currentTimeMillis()} and {@link System#nanoTime()}.
-     * While the named {@link System} methods do provide the required precision,
-     * <code>gettimeofday()</code> <i>also</i> guarantees time accuracy, i.e. update interval.
-     * </p>
-     * @see #currentTimeMillis()
+     * Returns the unix based current time in milliseconds, see {@link Clock#currentTimeMillis()}.
+     * @see Clock#currentTimeMillis()
      */
-    public static native long currentTimeMicros();
+    public static long currentTimeMillis() {
+        return Clock.currentTimeMillis();
+    }
 
     /**
      * Returns the estimated sleep jitter value in nanoseconds.