orca/src/platform/win32_clock.c

/*************************************************************************
*
*  Orca
*  Copyright 2023 Martin Fouilleul and the Orca project contributors
*  See LICENSE.txt for licensing information
*
**************************************************************************/
#include <profileapi.h>

#include "platform_clock.h"
#include "util/typedefs.h"

#ifdef __cplusplus
extern "C"
{
#endif

    static u64 __performanceCounterFreq = 0;

    const u64 WIN_EPOCH_TO_UNIX_EPOCH_100NS = 116444736000000000; // number of 100ns from Jan 1, 1601 (windows epoch) to  Jan 1, 1970 (unix epoch)

    void oc_clock_init()
    {
        LARGE_INTEGER freq;
        QueryPerformanceFrequency(&freq);
        __performanceCounterFreq = freq.QuadPart;
    }

    f64 oc_clock_time(oc_clock_kind clock)
    {
        switch(clock)
        {
            case OC_CLOCK_MONOTONIC:
            {
                LARGE_INTEGER counter;
                QueryPerformanceCounter(&counter);

                f64 time = __performanceCounterFreq ? (counter.QuadPart / (f64)__performanceCounterFreq) : 0;
                return (time);
            }

            case OC_CLOCK_UPTIME:
            {
                LONGLONG unbiasedTime100Ns;
                if(QueryUnbiasedInterruptTime(&unbiasedTime100Ns))
                {
                    f64 unbiasedTimeSecs = ((f64)unbiasedTime100Ns) / (10 * 1000 * 1000);
                    return unbiasedTimeSecs;
                }
                oc_log_error("OC_CLOCK_UPTIME syscall failed with error: %d", GetLastError());
                return 0;
            }

            case OC_CLOCK_DATE:
            {
                FILETIME ft;
                GetSystemTimeAsFileTime(&ft);

                u64 systemTime100Ns = ((u64)ft.dwHighDateTime << 32) | (u64)ft.dwLowDateTime;
                u64 timestamp100Ns = systemTime100Ns - WIN_EPOCH_TO_UNIX_EPOCH_100NS;
                f64 timeSecs = ((f64)timestamp100Ns) / (10 * 1000 * 1000);
                return timeSecs;
            }
        }

        return 0.0;
    }

#ifdef __cplusplus
} // extern "C"
#endif