How to create a Queue of unsigned char array in Qt? - qt

Question

I am new in Queue (FIFO) and Qt. I want to create a Queue of unsigned char array in Qt. How to do it? Please help
unsigned char buffer[1024];

Answer 1

If you want to use the Qt API, then you can use the QQueue class -
QQueue<unsigned char> queue;
queue.enqueue(65);
queue.enqueue(66);
queue.enqueue(67);
while (!queue.isEmpty())
cout << queue.dequeue() << endl;
If you want to build the queue on your own, then I guess you can declare a Queue class like this -
class Queue
{
private:
enum{SIZE=1024, EMPTY=0};
unsigned char buffer[SIZE];
int readHead, writeHead;
public:
Queue()
{
readHead = writeHead = EMPTY;
}
void push(unsigned char data);
unsigned char pop();
unsigned char peek();
bool isEmpty();
};
void Queue::push(unsigned char data)
{
if((readHead - writeHead) >= SIZE)
{
// You should handle Queue overflow the way you want here.
return;
}
buffer[writeHead++ % SIZE] = data;
}
unsigned char Queue::pop()
{
unsigned char item = peek();
readHead++;
return item;
}
unsigned char Queue::peek()
{
if(isEmpty())
{
// You should handle Queue underflow the way you want here.
return;
}
return buffer[readHead % SIZE];
}
bool Queue::isEmpty()
{
return (readHead == writeHead);
}
If you want to maintain a Queue of unsigned char array, then you will have to maintain a queue of unsigned char pointers -
QQueue<unsigned char *> queue;
unsigned char *array1 = new unsigned char[10]; // array of 10 items
array1[0] = 65;
array1[1] = 66;
queue.enqueue(array1);
unsigned char *array2 = new unsigned char[20]; // an array of 20 items
queue.enqueue(array2);
unsigned char *arr = queue.dequeue();
qDebug() << arr[0] << ", " << arr[1];
Note: You should take care of the memory cleanup after you are done with this queue. IMHO, you better avoid this type of design though.