Patch up CircularQueue

- Use `size` and `count` instead of `length` and `size`
- Fix bug: `peek` should return the item
- Clean up comments, spacing, spelling
master
Scott Lahteine 8 years ago
parent cebeb48005
commit f26d5425bf

@ -26,120 +26,119 @@
#include <Arduino.h>
/**
* @brief Circular Queue class
* @brief Circular Queue class
* @details Implementation of the classic ring buffer data structure
*/
template<typename T, int N>
template<typename T, uint8_t N>
class CircularQueue {
private:
/**
* @brief Buffer structure
* @brief Buffer structure
* @details This structure consolidates all the overhead required to handle
* a circular queue such as the pointers and the buffer vector.
* a circular queue such as the pointers and the buffer vector.
*/
struct buffer_t {
uint8_t head;
uint8_t tail;
uint8_t count;
uint8_t size;
uint8_t length;
T queue[N];
} buffer;
public:
/**
* @brief Class constructor
* @brief Class constructor
* @details This class requires two template parameters, T defines the type
* of the items this queue will handle and N defines the maximum number of
* items that can be stored on the queue.
* of item this queue will handle and N defines the maximum number of
* items that can be stored on the queue.
*/
CircularQueue<T, N>() {
this->buffer.length = N;
this->buffer.size = this->buffer.head = this->buffer.tail = 0;
this->buffer.size = N;
this->buffer.count = this->buffer.head = this->buffer.tail = 0;
}
/**
* @brief Removes and returns a item from the queue
* @details Removes the oldest item on the queue which is pointed by the
* buffer_t head variable, this item is then returned to the caller.
* @return type T item
* @brief Removes and returns a item from the queue
* @details Removes the oldest item on the queue, pointed to by the
* buffer_t head field. The item is returned to the caller.
* @return type T item
*/
T dequeue() {
if (this->isEmpty()) return T();
T const item = this->buffer.queue[this->buffer.head++];
--this->buffer.size;
uint8_t index = this->buffer.head;
if (this->buffer.head == this->buffer.length)
--this->buffer.count;
if (++this->buffer.head == this->buffer.size)
this->buffer.head = 0;
return item;
return this->buffer.queue[index];
}
/**
* @brief Adds an item to the queue
* @details Adds a item to the queue on the location pointed by the buffer_t
* tail vairable, will return false if there is no queue space available.
*
* @param item Item to be added to the queue
* @return true if the operation was successfull
* @brief Adds an item to the queue
* @details Adds an item to the queue on the location pointed by the buffer_t
* tail variable. Returns false if no queue space is available.
* @param item Item to be added to the queue
* @return true if the operation was successful
*/
bool enqueue(T const &item) {
if (this->isFull()) return false;
this->buffer.queue[this->buffer.tail++] = item;
++this->buffer.size;
this->buffer.queue[this->buffer.tail] = item;
if (this->buffer.tail == this->buffer.length)
++this->buffer.count;
if (++this->buffer.tail == this->buffer.size)
this->buffer.tail = 0;
return true;
}
/**
* @brief Checks if the queue has no items
* @brief Checks if the queue has no items
* @details Returns true if there are no items on the queue, false otherwise.
* @return true if queue is empty
* @return true if queue is empty
*/
bool isEmpty() {
return this->buffer.size == 0;
return this->buffer.count == 0;
}
/**
* @brief Checks if the queue is full
* @brief Checks if the queue is full
* @details Returns true if the queue is full, false otherwise.
* @return true if queue is full
* @return true if queue is full
*/
bool isFull() {
return this->buffer.size == this->buffer.length;
return this->buffer.count == this->buffer.size;
}
/**
* @brief Gets the queue size
* @brief Gets the queue size
* @details Returns the maximum number of items a queue can have.
* @return the queue lenght
* @return the queue size
*/
uint8_t length() {
return this->buffer.length;
uint8_t size() {
return this->buffer.size;
}
/**
* @brief Gets the next item from the queue without removing it
* @details Returns the next item on the queue but the item is not removed
* from the queue nor the pointers updated.
* @return the queue size
* @brief Gets the next item from the queue without removing it
* @details Returns the next item in the queue without removing it
* or updating the pointers.
* @return first item in the queue
*/
uint8_t peek() {
T peek() {
return this->buffer.queue[this->buffer.head];
}
/**
* @brief Gets the number of items on the queue
* @details Returns the current number of items stored on the queue.
* @return type T item
* @return number of items in the queue
*/
uint8_t size() {
return this->buffer.size;
uint8_t count() {
return this->buffer.count;
}
};

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