JEEP::JTimekeeper Class Reference

Time keeper. More...

#include <JTimekeeper.hh>

Inheritance diagram for JEEP::JTimekeeper:

Public Member Functions
	JTimekeeper ()
	Default constructor. More...
	JTimekeeper (const long long int interval_us)
	Constructor. More...
long long int	getInterval () const
	Get interval time. More...
long long int	getDelay () const
	Get total delay time. More...
void	setInterval (const long long int interval_us)
	Set interval time. More...
void	reset (const long long int t0)
	Reset time. More...
void	reset ()
	Reset time. More...
bool	operator() () const
	Check whether the number of time intervals has elapsed since the last call to the reset method. More...
void	wait () const
	Wait until the number of time intervals has elapsed since the last call to the reset method. More...
bool	wait (JFileDescriptorMask &mask) const
	Wait until the number of time intervals has elapsed since the last call to the reset method or input data have become available on one of the file descriptors in the given mask. More...

Protected Attributes
long long int	interval
	interval time [us] More...

Private Attributes
long long int	t0
	t0 of elapsed time [us] More...
long long int	total_delay
	total delay time [us] More...
long long int	counter
	interval counter More...

Detailed Description

Time keeper.

This class can be used to check whether elapsed time exceeds preset time interval or to wait until preset time interval has elapsed.

Definition at line 34 of file JTimekeeper.hh.

Constructor & Destructor Documentation

JEEP::JTimekeeper::JTimekeeper ( )

inline

Default constructor.

Definition at line 39 of file JTimekeeper.hh.

                  :
      interval   (0),
      total_delay(0),
      counter    (0)
    {
      reset();
    }

JEEP::JTimekeeper::JTimekeeper ( const long long int  interval_us )

inline

Constructor.

Parameters

interval_us

interval time [us]

Definition at line 53 of file JTimekeeper.hh.

                                                 :
      interval   (interval_us),
      total_delay(0),
      counter    (0)
    {
      reset();
    }

Member Function Documentation

long long int JEEP::JTimekeeper::getInterval ( ) const

inline

Get interval time.

Returns

interval time [us]

Definition at line 67 of file JTimekeeper.hh.

    {
      return interval;
    }

long long int JEEP::JTimekeeper::getDelay ( ) const

inline

Get total delay time.

Returns

delay time [us]

Definition at line 78 of file JTimekeeper.hh.

    {
      return total_delay;
    }

void JEEP::JTimekeeper::setInterval ( const long long int  interval_us )

inline

Set interval time.

Parameters

interval_us

interval time [us]

Definition at line 89 of file JTimekeeper.hh.

    {
      interval = interval_us;
    }

void JEEP::JTimekeeper::reset ( const long long int  t0 )

inline

Reset time.

Parameters

t0

time [us]

Definition at line 100 of file JTimekeeper.hh.

    {
      this->t0          = t0;
      this->counter     = 0;
      this->total_delay = 0;
    }

void JEEP::JTimekeeper::reset ( )

inline

Reset time.

Definition at line 111 of file JTimekeeper.hh.

    {
      reset(getLocalTime());
    }

bool JEEP::JTimekeeper::operator() ( ) const

inline

Check whether the number of time intervals has elapsed since the last call to the reset method.

The number of intervals is equal to the number of calls this method returned true since the last call to the reset method.

Returns

true if elapsed time exceeds interval time; else false

Definition at line 125 of file JTimekeeper.hh.

    {
      if (getLocalTime() >= t0 + (counter + 1) * interval) {

        ++counter;

        return true;

      } else

        return false;
    }

void JEEP::JTimekeeper::wait ( ) const

inline

Wait until the number of time intervals has elapsed since the last call to the reset method.

The number of intervals is equal to the number of calls to the method wait since the last call to the reset method.

Definition at line 145 of file JTimekeeper.hh.

    { 
      static const useconds_t MAXIMAL_SLEEP_TIME_US = std::numeric_limits<useconds_t>::max();

      long long int delay = t0  +  (counter + 1) * interval  -  getLocalTime();   // [us]

      while (delay > MAXIMAL_SLEEP_TIME_US && usleep(MAXIMAL_SLEEP_TIME_US) == 0) {

        total_delay += MAXIMAL_SLEEP_TIME_US;
        delay       -= MAXIMAL_SLEEP_TIME_US;
      }

      if (delay > 0 && usleep((useconds_t) delay) == 0) {
        total_delay += delay;
      }

      ++counter;
    }

bool JEEP::JTimekeeper::wait ( JFileDescriptorMask &  mask ) const

inline

Wait until the number of time intervals has elapsed since the last call to the reset method or input data have become available on one of the file descriptors in the given mask.

The number of intervals is equal to the number of calls to the method wait since the last call to the reset method. Note that the mask is overwritten following a select call.

Parameters

mask	input mask

Returns

true if interrupted; else false

Definition at line 176 of file JTimekeeper.hh.

    { 
      long long int t1    = getLocalTime();  
      long long int delay = t0  +  (counter + 1) * interval  -  t1;   // [us]

      // ensure one select call for each call to this method.

      if (delay < 0) {
        delay = 0;
      }

      JTimeval timeout((int) (delay/1000000), (int) (delay%1000000));

      if (mask.in_avail(timeout)) {

        total_delay += getLocalTime() - t1;
        
        return true;

      } else {

        ++counter;

        total_delay += delay;

        return false;
      }
    }

Member Data Documentation

long long int JEEP::JTimekeeper::interval

protected

interval time [us]

Definition at line 207 of file JTimekeeper.hh.

long long int JEEP::JTimekeeper::t0

mutableprivate

t0 of elapsed time [us]

Definition at line 210 of file JTimekeeper.hh.

long long int JEEP::JTimekeeper::total_delay

mutableprivate

total delay time [us]

Definition at line 211 of file JTimekeeper.hh.

long long int JEEP::JTimekeeper::counter

mutableprivate

interval counter

Definition at line 212 of file JTimekeeper.hh.

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The documentation for this class was generated from the following file:

• JTimekeeper.hh