WindowsPlatformTime.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "GenericPlatform/GenericPlatformTime.h"
#include "Windows/WindowsSystemIncludes.h"
 
 
/**
 * Windows implementation of the Time OS functions.
 *
 * Please see following UDN post about using rdtsc on processors that support
 * result being invariant across cores.
 *
 * https://udn.epicgames.com/lists/showpost.php?id=46794&list=unprog3
 */
struct FWindowsPlatformTime
    : public FGenericPlatformTime
{
    static double InitTiming();
 
    static FORCEINLINE double Seconds()
    {
        Windows::LARGE_INTEGER Cycles;
        Windows::QueryPerformanceCounter(&Cycles);
 
        // add big number to make bugs apparent where return value is being passed to float
        return (double)Cycles.QuadPart * GetSecondsPerCycle() + 16777216.0;
    }
 
    static FORCEINLINE uint32 Cycles()
    {
        Windows::LARGE_INTEGER Cycles;
        Windows::QueryPerformanceCounter(&Cycles);
        return (uint32)Cycles.QuadPart;
    }
 
    static FORCEINLINE uint64 Cycles64()
    {
        Windows::LARGE_INTEGER Cycles;
        QueryPerformanceCounter(&Cycles);
        return Cycles.QuadPart;
    }
 
 
    static void SystemTime( int32& Year, int32& Month, int32& DayOfWeek, int32& Day, int32& Hour, int32& Min, int32& Sec, int32& MSec );
    static void UtcTime( int32& Year, int32& Month, int32& DayOfWeek, int32& Day, int32& Hour, int32& Min, int32& Sec, int32& MSec );
 
    static bool UpdateCPUTime( float DeltaTime );
    static bool UpdateThreadCPUTime(float = 0.0);
    static void AutoUpdateGameThreadCPUTime(double UpdateInterval);
    static FCPUTime GetCPUTime();
    static FCPUTime GetThreadCPUTime();
    static double GetLastIntervalThreadCPUTimeInSeconds();
 
protected:
 
    /** Percentage CPU utilization for the last interval relative to one core. */
    static float CPUTimePctRelative;
};
 
 
typedef FWindowsPlatformTime FPlatformTime;