Queue

Functions
void	queue_init (queue_t *queue, queue_array_t *queueArray, uint16_t queueSize, uint8_t dataSize)
uint8_t	queue_enqueue (queue_t *queue, const void *value)
uint8_t	queue_dequeue (queue_t *queue, void *value)
void	queue_print (queue_t *queue, void(*printFn)(const void *data), void *data)
uint16_t	queue_count (queue_t *queue)

Detailed Description

Function Documentation

queue_count()

uint16_t queue_count

(

queue_t *

queue

)

Description:

This function is used to get the number of elements in the queue.

Parameters

queue

Queue to get the number of elements.

Returns

Number of elements.

queue_dequeue()

uint8_t queue_dequeue	(	queue_t *	queue,
		void *	value
	)

Description:

This function is used to get a element from the queue.

Parameters

queue	Queue.
value	Pointer to variable to which the dequeued data will be copied.

Returns

-1 if the queue is empty (underflow), 0 otherwise.

Example:

#define QUEUESIZE   sizeof(uint16_t) * 10

uint8_t error;
uint16_t data, retval;
queue_t queue;
queue_array_t queue_array[QUEUESIZE] = {0};

queue_init(&queue, queue_array, QUEUESIZE, sizeof(uint16_t));

data = 1;
int error = queue_enqueue(&queue, (void *) &data);
int error = queue_dequeue(&queue, (void *) &retval);

queue_enqueue()

uint8_t queue_enqueue	(	queue_t *	queue,
		const void *	value
	)

Description:

This function is used to put a element in the queue.

Parameters

queue	Queue.
value	Pointer to variable whose value is going to be inserted to the queue.

Returns

-1 if the queue is full (overflow), 0 otherwise.

Example:

#define QUEUESIZE   sizeof(uint16_t) * 10

uint8_t error;
uint16_t data;
queue_t queue;
queue_array_t queue_array[QUEUESIZE] = {0};

queue_init(&queue, queue_array, QUEUESIZE, sizeof(uint16_t));

data = 1;
int error = queue_enqueue(&queue, (void *) &data);

queue_init()

void queue_init	(	queue_t *	queue,
		queue_array_t *	queueArray,
		uint16_t	queueSize,
		uint8_t	dataSize
	)

Description:

This function is used to initialize a queue structure.

Parameters

queue	Queue to be initialized.
queueArray	Pointer to the array used to store the data.
queueSize	Size of the queue array.
dataSize	Size of every data element.

Returns

None.

Example:

#define QUEUESIZE   sizeof(uint16_t) * 10

queue_t queue;
queue_array_t queue_array[QUEUESIZE] = {0};

queue_init(&queue, queue_array, QUEUESIZE, sizeof(uint16_t));

queue_print()

void queue_print	(	queue_t *	queue,
		void(*)(const void *data)	printFn,
		void *	data
	)

Description:

This function is used to print the values of the queue.

Parameters

queue	Queue.
printFn	Pointer to the function used to print the elements.
data	Pointer to a variable with the correct size that will store every element of the queue and is passed to printFn.

Returns

None.

Example:

#define QUEUESIZE   sizeof(uint16_t) * 3

void 
printUint16(const void *data)
{
    printf("%d :: ", *((const uint16_t *) data));
}

int
main(int argc, char** argv)
{
    uint8_t error, i;
    uint16_t print_data;
    const uint16_t data[3] = {0, 1, 2};
    queue_t queue;
    queue_array_t queue_array[QUEUESIZE] = {0};

    queue_init(&queue, queue_array, QUEUESIZE, sizeof(uint16_t));

    for (i = 0; i < 3; i++)
    {
        int error = queue_enqueue(&queue, (void *) &data[i]);
    }

    queue_print(queue, printUint16, (void *) &print_data);
}