UnixPlatformTime.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================================
    UnixPlatformTime.h: Unix platform Time functions
==============================================================================================*/
 
#pragma once
 
#include "CoreTypes.h"
#include "GenericPlatform/GenericPlatformTime.h"
 
#include <time.h> // IWYU pragma: export
 
struct FUnixTime : public FGenericPlatformTime
{
    static CORE_API double InitTiming();
 
    static inline double Seconds()
    {
        if (UNLIKELY(ClockSource < 0))
        {
            ClockSource = CalibrateAndSelectClock();
        }
 
        struct timespec ts;
        clock_gettime(ClockSource, &ts);
        return static_cast<double>(ts.tv_sec) + static_cast<double>(ts.tv_nsec) / 1e9;
    }
 
    static inline uint32 Cycles()
    {
        if (UNLIKELY(ClockSource < 0))
        {
            ClockSource = CalibrateAndSelectClock();
        }
 
        struct timespec ts;
        clock_gettime(CLOCK_MONOTONIC, &ts);
        return static_cast<uint32>(static_cast<uint64>(ts.tv_sec) * (uint64)1e6 + static_cast<uint64>(ts.tv_nsec) / 1000ULL);
    }
 
    static inline uint64 Cycles64()
    {
        struct timespec ts;
        clock_gettime(CLOCK_MONOTONIC, &ts);
        return static_cast<uint64>(static_cast<uint64>(ts.tv_sec) * (uint64)1e7 + static_cast<uint64>(ts.tv_nsec) / 100ULL);
    }
 
    static CORE_API bool UpdateCPUTime(float DeltaSeconds);
    static CORE_API bool UpdateThreadCPUTime(float = 0.0);
    static CORE_API void AutoUpdateGameThreadCPUTime(double UpdateInterval);
 
    static CORE_API FCPUTime GetCPUTime();
    static CORE_API FCPUTime GetThreadCPUTime();
    static CORE_API double GetLastIntervalThreadCPUTimeInSeconds();
 
    static CORE_API void PrintCalibrationLog();
 
    UE_INTERNAL static int GetClockSource()
    {
        return ClockSource;
    }
 
private:
 
    static CORE_API int ClockSource;
 
    static CORE_API char CalibrationLog[4096];
 
    static CORE_API int CalibrateAndSelectClock();
 
    static CORE_API uint64 CallsPerSecondBenchmark(clockid_t BenchClockId, const char * BenchClockIdName);
};
 
typedef FUnixTime FPlatformTime;