redux::frames::Frame< T > Class Template Reference

#include <Frame.h>

Public Member Functions
	Frame (T value, units::second_t timestamp)
void	Update (T value, units::second_t timestamp)
FrameData< T >	GetFrameData ()
T	GetValue ()
units::second_t	GetTimestamp ()
uint32_t	AddCallback (std::function< void(FrameData< T >)> callback)
bool	RemoveCallback (uint32_t key)
void	AddListener (FrameListener< T > *listener)
void	RemoveListener (FrameListener< T > *listener)

Detailed Description

template<typename T>
class redux::frames::Frame< T >

Class representing periodic timestamped data received from CAN or other sources.

For applications like latency compensation, we often need both sensor/device data and a timestamp of when the data was received. Frames provide this by holding the most recently received raw data and the timestamps they were received at and allowing retrieval of both data and timestamps in one FrameData object via Frame.GetFrameData(), avoiding race conditions involving reading data and timestamp separately. Additionally, they allow for synchronous reads through WaitForFrames by notifying when new data has been received.

Constructor & Destructor Documentation

Frame()

template<typename T >

redux::frames::Frame< T >::Frame ( T  value, units::second_t  timestamp  )

inline

Constructs a new Frame object.

Parameters

value	The initial value to hold.
timestamp	The initial timestamp at which the value was received in seconds.

Member Function Documentation

AddCallback()

template<typename T >

uint32_t redux::frames::Frame< T >::AddCallback ( std::function< void(FrameData< T >)>  callback )

inline

Add a callback that will be run whenever this Frame gets updated. Example application (may not be applicable)

// Log Canandcoder position FrameData.
std::vector<FrameData<units::turn_t>> position_packets;
redux::sensors::canandcoder::Canandcoder enc0{0};
 
enc0.GetPositionFrame().AddCallback([&](FrameData<units::turn_t> frameData) {
    position_packets.push_back(frameData);
});
// Timestamped data is now appended to the Vector.

Parameters

callback

the callback

Returns

an handle key that can be used to unregister the callback later

AddListener()

template<typename T >

void redux::frames::Frame< T >::AddListener ( FrameListener< T > *  listener )

inline

Internal use function (for WaitForFrames)

Parameters

listener

listener pointer to add

GetFrameData()

template<typename T >

FrameData< T > redux::frames::Frame< T >::GetFrameData ( )

inline

Fetches an immutable FrameData snapshot of the currently stored values

Returns

FrameData of value/timestamp pair

GetTimestamp()

template<typename T >

units::second_t redux::frames::Frame< T >::GetTimestamp ( )

inline

Gets the timestamp in seconds of when this frame was last updated.

Returns

the timestamp in seconds.

GetValue()

template<typename T >

T redux::frames::Frame< T >::GetValue ( )

inline

Returns the current frame's value.

Returns

the value the data frame holds.

RemoveCallback()

template<typename T >

bool redux::frames::Frame< T >::RemoveCallback ( uint32_t  key )

inline

Unregister a callback run whenever this Frame gets updated.

Parameters

key	the key returned by AddCallback

Returns

true on unregister, false if the callback didn't exist

RemoveListener()

template<typename T >

void redux::frames::Frame< T >::RemoveListener ( FrameListener< T > *  listener )

inline

Internal use function (for WaitForFrames)

Parameters

listener

listener pointer to remove. you must remove your listener before the end of its life or you will cause memory corruption

Update()

template<typename T >

void redux::frames::Frame< T >::Update ( T  value, units::second_t  timestamp  )

inline

Updates the Frame's value, notifying any listeners of new data.

Parameters

value	the new value
timestamp	the new timestamp of the received data

---

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

• src/main/native/include/redux/frames/Frame.h