This class implements a templated standard FiFo-queue for inter process communication (arbitrary number of readers/writers), e.g. More...

#include <Base/Common/FiFoQueue.hh>

Public Member Functions
int	AppendSynced (T &item)
	Append an datum as newest item. More...

int	AppendUnsynced (T &item)
	Append an datum as newest item. More...

int	FetchSynced (T &item)
	Fetch the oldest item from the queue. More...

int	FetchUnsynced (T &item)
	Fetch the oldest item from the queue. More...

	FiFoQueue ()
	Default constructor. More...

	FiFoQueue (unsigned length)
	Constructor. More...

unsigned	GetBufferSize ()
	Returns the size of underlying ringbuffer -> maximum number of items in queue. More...

unsigned	GetNumItems ()
	Return the number of items in queue. More...

	~FiFoQueue ()
	Just a cleanup. More...

Protected Member Functions
	FiFoQueue (FiFoQueue &data)

Protected Attributes
T *	data_
	array holding cycled buffer More...

unsigned	head_
	first (oldest) element in queue More...

const unsigned	length_
	length of buffer (number of slots) More...

unsigned	numItems_
	number of items in buffer More...

pthread_mutex_t *	syncMutex_
	mutex for sync. locking (conditions and access) More...

unsigned	tail_
	last (newest) element in queue More...

pthread_cond_t *	triggerCondEmpty_
	pthread condition variable for waiting for non empty buf More...

pthread_cond_t *	triggerCondFull_
	pthread condition variable for waiting for non full buf More...

Detailed Description

template<class T>
class BIAS::FiFoQueue< T >

This class implements a templated standard FiFo-queue for inter process communication (arbitrary number of readers/writers), e.g.

    between GUIs and underlying processes. It can be used as synced or
    unsynced.
    FiFo: Oldest item will be return at first. Items once fetched are
    'deleted' from the queue.
    synced:   process is block until a free slot available for writing
              -> AppendSynced
              or an item is available for read
              -> FetchSynced
    unsynced: no item is returned from empty buffer when reading and
              oldest item gets 'lost' when buffer is full during
              writing
    !!! ATTENTION: WHEN TEMPLATED OVER POINTERS DATA 'BEHIND' !!!
    !!! THE POINTER WON'T DELETED WHEN BUFFER IS FULL DURING  !!!
    !!! WRITING                                               !!!

Author: BIAS

Definition at line 60 of file FiFoQueue.hh.

Constructor & Destructor Documentation

template<class T>

BIAS::FiFoQueue< T >::FiFoQueue ( )

inline

Default constructor.

Creates a queue with defined default size BIAS_FIFOQUEUE_DEFAULT_SIZE and initializes mutex-/condition- variables

Definition at line 67 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::triggerCondEmpty_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

BIAS::FiFoQueue< T >::FiFoQueue ( unsigned length )

inline

Constructor.

Creates a queue with given size and initializes mutex-/condition-variables

Definition at line 84 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::length_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::triggerCondEmpty_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

BIAS::FiFoQueue< T >::~FiFoQueue ( )

inline

Just a cleanup.

!!! ATTENTION: WHEN USING POINTERS AS TEMPLATE TYPE ONLY THE !!! !!! BUFFER IS DELETED - NOT THE DATA 'BEHIND' THE POINTERS !!!

Definition at line 102 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::triggerCondEmpty_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

BIAS::FiFoQueue< T >::FiFoQueue ( FiFoQueue< T > & data )

inlineprotected

Definition at line 266 of file FiFoQueue.hh.

Member Function Documentation

template<class T>

int BIAS::FiFoQueue< T >::AppendSynced ( T & item )

inline

Append an datum as newest item.

Syncron in the sens of blocking, that is, threads inserting an item to a full queue are delayed until a slot is available (item has been fetched)

Definition at line 136 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::head_, BIAS::FiFoQueue< T >::length_, BIAS::FiFoQueue< T >::numItems_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::tail_, BIAS::FiFoQueue< T >::triggerCondEmpty_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

int BIAS::FiFoQueue< T >::AppendUnsynced ( T & item )

inline

Append an datum as newest item.

Asyncron in the sens of non-blocking, that is, threads inserting an item to a full queue will overwrite the oldest item. This gets 'lost'. !!! ATTENTION: OVERWRITING A POINTER TYPE DOES NO FREE MEMORY !!!

Definition at line 169 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::head_, BIAS::FiFoQueue< T >::length_, BIAS::FiFoQueue< T >::numItems_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::tail_, and BIAS::FiFoQueue< T >::triggerCondEmpty_.

template<class T>

int BIAS::FiFoQueue< T >::FetchSynced ( T & item )

inline

Fetch the oldest item from the queue.

Again synced is blocking, thread will wait for an item if buffer is empty.

Definition at line 203 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::head_, BIAS::FiFoQueue< T >::length_, BIAS::FiFoQueue< T >::numItems_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::tail_, BIAS::FiFoQueue< T >::triggerCondEmpty_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

int BIAS::FiFoQueue< T >::FetchUnsynced ( T & item )

inline

Fetch the oldest item from the queue.

Again unsynced is non-blocking, thread won't wait for an item if buffer is empty. In this case the input-/ output-param is left unchanged and 1 is returned.

Definition at line 235 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::data_, BIAS::FiFoQueue< T >::length_, BIAS::FiFoQueue< T >::numItems_, BIAS::FiFoQueue< T >::syncMutex_, BIAS::FiFoQueue< T >::tail_, and BIAS::FiFoQueue< T >::triggerCondFull_.

template<class T>

unsigned BIAS::FiFoQueue< T >::GetBufferSize ( )

inline

Returns the size of underlying ringbuffer -> maximum number of items in queue.

Definition at line 128 of file FiFoQueue.hh.

References BIAS::FiFoQueue< T >::length_.

template<class T>

unsigned BIAS::FiFoQueue< T >::GetNumItems ( )

inline

Return the number of items in queue.