libgfaservices/datalogger/dataloggerclock.cpp

//////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////

#include <errno.h>
#include "datalogger.h"

//////////////////////////////////////////////////////////////////////////////////

CDataLoggerClock::CDataLoggerClock(unsigned long long nSampleTimeNs) : m_nSampleTimeNs(nSampleTimeNs)
{
	m_fSleepStarted = false;
}

CDataLoggerClock::~CDataLoggerClock(void)
{
}

//////////////////////////////////////////////////////////////////////////////////

unsigned long long CDataLoggerClock::GetNanoTick(struct timespec *pts)
{
	struct timespec ts;
	if(!pts)
		pts = &ts;
	clock_gettime(CLOCK_MONOTONIC, pts);
	return Timespec2NanoSec(pts);
}

bool CDataLoggerClock::Sleep(bool &bTimerUnderrun, bool fAvoidCatchUpRaceOnTimerUnderrun)
{
	int nRet;
	unsigned long long dt;

	if(!m_fSleepStarted)
	{
		clock_gettime(CLOCK_MONOTONIC, &m_tsDueTime);
		m_fSleepStarted = true;
		return true;
	}

	dt = IncTime(&m_tsDueTime, m_nSampleTimeNs);

	if(fAvoidCatchUpRaceOnTimerUnderrun)
	{
		if(dt < GetNanoTick())
		{
			bTimerUnderrun = true;
			clock_gettime(CLOCK_MONOTONIC, &m_tsDueTime);
			return true;
		}
	}

	if((nRet = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &m_tsDueTime, NULL)))
	{
		while(nRet && (errno == EINTR))
		{
			errno = 0;
			nRet = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &m_tsDueTime, NULL);
		}
	}

	return !nRet;
}