ArRingQueue< T > Class Template Reference

#include <ArRingQueue.h>

List of all members.

---

Detailed Description

template<class T>
class ArRingQueue< T >

An expanding ring queue.

It is used to keep a queue with a minimum of allocation and freeing of heap memory. The ring queue is implemented using std::list. The queue starts with an initial capacity, but those initial items are considered 'unused'. Items are "pushed" into the queue at the "back", and "popped" from the queue at the "front". pop() and advance_front() will move the front of the queue to the next item, creating a new 'unused slot' for future use; advance_back() changes the next item in the back to a 'used' slot. push() either uses the next 'unused' slot, or inserts a new item into the std::list. When the capacity of the queue is filled, all operations will fail except push(). Use push() to insert new items in the queue and increase its capacity.

Todo:

Ideally, this class would be fully threadsafe (with occasional or no mutex locking), but it is not currently.

Todo:

Optionally allocate several future 'slots' instead of just one.

Definition at line 55 of file ArRingQueue.h.

Public Member Functions
void	advance_back ()
void	advance_front ()
	ArRingQueue (int capacity, T init_value)
std::list< T >::iterator	back ()
size_t	capacity ()
bool	empty ()
std::list< T >::iterator	front ()
bool	full ()
std::list< T >::iterator	nil ()
T	pop ()
T	pop_front ()
void	print ()
void	push (const T &item)
void	push_back (const T &item)
void	push_without_expanding (const T &item)
void	reset ()
size_t	size ()
Protected Attributes
std::list< T >::iterator	back_it
size_t	curSize
std::list< T >::iterator	front_it
T	initval
std::list< T >	ring

---

Constructor & Destructor Documentation

template<class T> ArRingQueue< T >::ArRingQueue (  int  capacity, T  init_value )  [inline]

Parameters: capacity  Initial capacity of the ring queue. init_value  Initial value for new, unused items in the queue. Definition at line 60 of file ArRingQueue.h.

---

Member Function Documentation

template<class T> void ArRingQueue< T >::advance_back (   )  [inline]

Advance the back (an 'empty' push), if the queue is not full. 'Used' size will be incremented. Definition at line 117 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::advance_front (   )  [inline]

Advance the front: an 'empty' pop. 'Used' size will be decremented. Definition at line 103 of file ArRingQueue.h.

template<class T> std::list<T>::iterator ArRingQueue< T >::back (   )  [inline]

Get an iterator for the back of the queue (the item that would be replaced by push()). This is not the last item in the queue, rather it is the next, unused, "slot". If the queue is full, an iterator equivalent to that returned by nil() is returned. To add an item to the queue without pushing a copy with push(), first check if the queue is full (in which case you must push() your item). Then use this function to write the data into the next unused 'slot'. Then call advance_back to advance the back of the queue to your new item. Definition at line 93 of file ArRingQueue.h.

template<class T> size_t ArRingQueue< T >::capacity (   )  [inline]

Get the current capacity of the queue. Definition at line 193 of file ArRingQueue.h.

template<class T> bool ArRingQueue< T >::empty (  void   )  [inline]

Return true if the queue is empty (has no 'used' items), false otherwise. Definition at line 198 of file ArRingQueue.h.

template<class T> std::list<T>::iterator ArRingQueue< T >::front (   )  [inline]

Get an iterator for the front item of the ring queue (the item that would be returned by pop()). If the queue is currently empty, nil() will be returned. To remove an item from the queue without making a copy with pop(), first check if the queue is empty(). Then use this function to get the data. Then call advance_front(). Definition at line 76 of file ArRingQueue.h.

template<class T> bool ArRingQueue< T >::full (   )  [inline]

Return true if the queue is full, false otherwise. Definition at line 212 of file ArRingQueue.h.

template<class T> std::list<T>::iterator ArRingQueue< T >::nil (   )  [inline]

Return an iterator representing an invalid item. Compare to the return values of front(), back(), pop(), etc. Definition at line 218 of file ArRingQueue.h.

template<class T> T ArRingQueue< T >::pop (   )  [inline]

Remove the next item from the queue and return a copy of it. If the queue is empty, nil() will be returned. Definition at line 163 of file ArRingQueue.h.

template<class T> T ArRingQueue< T >::pop_front (   )  [inline]

Same as pop() Definition at line 171 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::print (   )  [inline]

Print the current contents of the queue. Python Wrapper Library: use printQueue() instead of print() (which is a reserved word in Python) Definition at line 176 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::push (  const T &  item  )  [inline]

Add an item to the back of the ring queue. If the queue is full, the capacity of the queue will be expanded and the item will be inserted. Definition at line 140 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::push_back (  const T &  item  )  [inline]

Same as push() Definition at line 150 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::push_without_expanding (  const T &  item  )  [inline]

Push a new item, but preserve capacity: instead of expanding the queue if full, then the oldest item is replaced and the front is advanced. Definition at line 155 of file ArRingQueue.h.

template<class T> void ArRingQueue< T >::reset (  void   )  [inline]

Logically clear the queue, resetting to initial empty state, but preserving current capacity, and leaving all contents as they are; the contents are not destroyed, but will be when replaced by new data later. Definition at line 205 of file ArRingQueue.h.

template<class T> size_t ArRingQueue< T >::size (   )  [inline]

Get the number of items currently 'used' in the queue. Definition at line 188 of file ArRingQueue.h.

---

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

• ArRingQueue.h

---