CircularQueue< T, N > Class Template Reference

Circular Queue class. More...

#include <circularqueue.h>

Public Member Functions
	CircularQueue ()
	Class constructor. More...
T	dequeue ()
	Removes and returns a item from the queue. More...
bool	enqueue (T const &item)
	Adds an item to the queue. More...
bool	isEmpty ()
	Checks if the queue has no items. More...
bool	isFull ()
	Checks if the queue is full. More...
uint8_t	size ()
	Gets the queue size. More...
T	peek ()
	Gets the next item from the queue without removing it. More...
uint8_t	count ()
	Gets the number of items on the queue. More...

Detailed Description

template<typename T, uint8_t N>
class CircularQueue< T, N >

Circular Queue class.

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Based on Sprinter and grbl. Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm

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Implementation of the classic ring buffer data structure

Constructor & Destructor Documentation

CircularQueue()

template<typename T, uint8_t N>

CircularQueue< T, N >::CircularQueue

(

)

Class constructor.

This class requires two template parameters, T defines the type of item this queue will handle and N defines the maximum number of items that can be stored on the queue.

                          {
      buffer.size = N;
      buffer.count = buffer.head = buffer.tail = 0;
    }

Member Function Documentation

dequeue()

template<typename T, uint8_t N>

T CircularQueue< T, N >::dequeue

(

)

Removes and returns a item from the queue.

Removes the oldest item on the queue, pointed to by the buffer_t head field. The item is returned to the caller.

Returns

type T item

                {
      if (isEmpty()) return T();
 
      uint8_t index = buffer.head;
 
      --buffer.count;
      if (++buffer.head == buffer.size)
        buffer.head = 0;
 
      return buffer.queue[index];
    }

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enqueue()

template<typename T, uint8_t N>

bool CircularQueue< T, N >::enqueue

(

T const &

item

)

Adds an item to the queue.

Adds an item to the queue on the location pointed by the buffer_t tail variable. Returns false if no queue space is available.

Parameters

item	Item to be added to the queue

Returns

true if the operation was successful

                                {
      if (isFull()) return false;
 
      buffer.queue[buffer.tail] = item;
 
      ++buffer.count;
      if (++buffer.tail == buffer.size)
        buffer.tail = 0;
 
      return true;
    }

isEmpty()

template<typename T, uint8_t N>

bool CircularQueue< T, N >::isEmpty

(

)

Checks if the queue has no items.

Returns true if there are no items on the queue, false otherwise.

Returns

true if queue is empty

{ return buffer.count == 0; }

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isFull()

template<typename T, uint8_t N>

bool CircularQueue< T, N >::isFull

(

)

Checks if the queue is full.

Returns true if the queue is full, false otherwise.

Returns

true if queue is full

{ return buffer.count == buffer.size; }

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size()

template<typename T, uint8_t N>

uint8_t CircularQueue< T, N >::size

(

)

Gets the queue size.

Returns the maximum number of items a queue can have.

Returns

the queue size

{ return buffer.size; }

peek()

template<typename T, uint8_t N>

T CircularQueue< T, N >::peek

(

void

)

Gets the next item from the queue without removing it.

Returns the next item in the queue without removing it or updating the pointers.

Returns

first item in the queue

{ return buffer.queue[buffer.head]; }

count()

template<typename T, uint8_t N>

uint8_t CircularQueue< T, N >::count

(

)

Gets the number of items on the queue.

Returns the current number of items stored on the queue.

Returns

number of items in the queue

{ return buffer.count; }