1 files changed, 92 insertions, 0 deletions
diff --git a/src/zenutil/filteredrate.cpp b/src/zenutil/filteredrate.cpp
new file mode 100644
index 000000000..de01af57b
--- /dev/null
+++ b/src/zenutil/filteredrate.cpp
@@ -0,0 +1,92 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenutil/filteredrate.h>
+
+namespace zen {
+
+void
+FilteredRate::Start()
+{
+	if (StartTimeUS == (uint64_t)-1)
+	{
+		uint64_t Expected = (uint64_t)-1;
+		if (StartTimeUS.compare_exchange_strong(Expected, Timer.GetElapsedTimeUs()))
+		{
+			LastTimeUS = StartTimeUS.load();
+		}
+	}
+}
+
+void
+FilteredRate::Stop()
+{
+	if (EndTimeUS == (uint64_t)-1)
+	{
+		uint64_t Expected = (uint64_t)-1;
+		EndTimeUS.compare_exchange_strong(Expected, Timer.GetElapsedTimeUs());
+	}
+}
+
+void
+FilteredRate::Update(uint64_t Count)
+{
+	if (LastTimeUS == (uint64_t)-1)
+	{
+		return;
+	}
+	uint64_t TimeUS		 = Timer.GetElapsedTimeUs();
+	uint64_t TimeDeltaUS = TimeUS - LastTimeUS;
+	if (TimeDeltaUS >= 2000000)
+	{
+		uint64_t Delta	   = Count - LastCount;
+		uint64_t PerSecond = (Delta * 1000000) / TimeDeltaUS;
+
+		FilteredPerSecond = (PerSecond + (LastPerSecond * 7)) / 8;
+
+		LastPerSecond = PerSecond;
+		LastCount	  = Count;
+		LastTimeUS	  = TimeUS;
+	}
+}
+
+uint64_t
+FilteredRate::GetCurrent() const
+{
+	if (LastTimeUS == (uint64_t)-1)
+	{
+		return 0;
+	}
+	return FilteredPerSecond;
+}
+
+uint64_t
+FilteredRate::GetElapsedTimeUS() const
+{
+	if (StartTimeUS == (uint64_t)-1)
+	{
+		return 0;
+	}
+	if (EndTimeUS == (uint64_t)-1)
+	{
+		return 0;
+	}
+	return EndTimeUS - StartTimeUS;
+}
+
+bool
+FilteredRate::IsActive() const
+{
+	return (StartTimeUS != (uint64_t)-1) && (EndTimeUS == (uint64_t)-1);
+}
+
+uint64_t
+GetBytesPerSecond(uint64_t ElapsedWallTimeUS, uint64_t Count)
+{
+	if (ElapsedWallTimeUS == 0)
+	{
+		return 0;
+	}
+	return Count * 1000000 / ElapsedWallTimeUS;
+}
+
+}  // namespace zen