145 lines
4.1 KiB
C++
145 lines
4.1 KiB
C++
/**
|
|
* Marlin 3D Printer Firmware
|
|
* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
|
|
*
|
|
* Based on Sprinter and grbl.
|
|
* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*/
|
|
|
|
#ifndef __CIRCULARQUEUE_H__
|
|
#define __CIRCULARQUEUE_H__
|
|
|
|
#include <stdint.h>
|
|
|
|
/**
|
|
* @brief Circular Queue class
|
|
* @details Implementation of the classic ring buffer data structure
|
|
*/
|
|
template<typename T, uint8_t N>
|
|
class CircularQueue {
|
|
private:
|
|
|
|
/**
|
|
* @brief Buffer structure
|
|
* @details This structure consolidates all the overhead required to handle
|
|
* 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;
|
|
T queue[N];
|
|
} buffer;
|
|
|
|
public:
|
|
/**
|
|
* @brief Class constructor
|
|
* @details 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.
|
|
*/
|
|
CircularQueue<T, N>() {
|
|
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, 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();
|
|
|
|
uint8_t index = this->buffer.head;
|
|
|
|
--this->buffer.count;
|
|
if (++this->buffer.head == this->buffer.size)
|
|
this->buffer.head = 0;
|
|
|
|
return this->buffer.queue[index];
|
|
}
|
|
|
|
/**
|
|
* @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.count;
|
|
if (++this->buffer.tail == this->buffer.size)
|
|
this->buffer.tail = 0;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @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
|
|
*/
|
|
bool isEmpty() {
|
|
return this->buffer.count == 0;
|
|
}
|
|
|
|
/**
|
|
* @brief Checks if the queue is full
|
|
* @details Returns true if the queue is full, false otherwise.
|
|
* @return true if queue is full
|
|
*/
|
|
bool isFull() {
|
|
return this->buffer.count == this->buffer.size;
|
|
}
|
|
|
|
/**
|
|
* @brief Gets the queue size
|
|
* @details Returns the maximum number of items a queue can have.
|
|
* @return the queue size
|
|
*/
|
|
uint8_t size() {
|
|
return this->buffer.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
|
|
*/
|
|
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 number of items in the queue
|
|
*/
|
|
uint8_t count() {
|
|
return this->buffer.count;
|
|
}
|
|
};
|
|
|
|
#endif
|