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/*!
    \class Q3PtrQueue
    \brief The Q3PtrQueue class is a template class that provides a queue.
    \compat

    Q3ValueVector can be used as an STL-compatible alternative to this
    class.

    A template instance Q3PtrQueue\<X\> is a queue that operates on
    pointers to X (X*).

    A queue is a first in, first out structure. Items are added to the
    tail of the queue with enqueue() and retrieved from the head with
    dequeue(). You can peek at the head item without dequeing it using
    head().

    You can control the queue's deletion policy with setAutoDelete().

    For compatibility with the Q3PtrCollection classes, current() and
    remove() are provided; both operate on the head().

    \sa Q3PtrList Q3PtrStack
*/

/*!
    \fn Q3PtrQueue::Q3PtrQueue ()

    Creates an empty queue with autoDelete() set to FALSE.
*/

/*!
    \fn Q3PtrQueue::Q3PtrQueue( const Q3PtrQueue<type>& queue )

    Creates a queue from \a queue.

    Only the pointers are copied; the items are not. The autoDelete()
    flag is set to FALSE.
*/

/*!
    \fn Q3PtrQueue::~Q3PtrQueue()

    Destroys the queue. Items in the queue are deleted if autoDelete()
    is TRUE.
*/

/*!
    \fn Q3PtrQueue<type>& Q3PtrQueue::operator= (const Q3PtrQueue<type>& queue)

    Assigns \a queue to this queue and returns a reference to this
    queue.

    This queue is first cleared and then each item in \a queue is
    enqueued to this queue. Only the pointers are copied.

    \warning The autoDelete() flag is not modified. If it is TRUE for
    both \a queue and this queue, deleting the two lists will cause \e
    double-deletion of the items.
*/

/*!
    \fn bool Q3PtrQueue::isEmpty() const

    Returns TRUE if the queue is empty; otherwise returns FALSE.

    \sa count() dequeue() head()
*/

/*!
    \fn void Q3PtrQueue::enqueue (const type* d)

    Adds item \a d to the tail of the queue.

    \sa count() dequeue()
*/

/*!
    \fn type* Q3PtrQueue::dequeue ()

    Takes the head item from the queue and returns a pointer to it.
    Returns 0 if the queue is empty.

    \sa enqueue() count()
*/

/*!
    \fn bool Q3PtrQueue::remove()

    Removes the head item from the queue, and returns TRUE if there
    was an item, i.e. the queue wasn't empty; otherwise returns FALSE.

    The item is deleted if autoDelete() is TRUE.

    \sa head() isEmpty() dequeue()
*/

/*!
    \fn void Q3PtrQueue::clear()

    Removes all items from the queue, and deletes them if autoDelete()
    is TRUE.

    \sa remove()
*/

/*!
    \fn uint Q3PtrQueue::count() const

    Returns the number of items in the queue.

    \sa isEmpty()
*/

/*!
    \fn type* Q3PtrQueue::head() const

    Returns a pointer to the head item in the queue. The queue is not
    changed. Returns 0 if the queue is empty.

    \sa dequeue() isEmpty()
*/

/*!
    \fn Q3PtrQueue::operator type*() const

    Returns a pointer to the head item in the queue. The queue is not
    changed. Returns 0 if the queue is empty.

    \sa dequeue() isEmpty()
*/

/*!
    \fn type* Q3PtrQueue::current() const

    Returns a pointer to the head item in the queue. The queue is not
    changed. Returns 0 if the queue is empty.

    \sa dequeue() isEmpty()
*/

/*!
    \fn bool Q3PtrQueue::autoDelete() const
    
    Returns the setting of the auto-delete option. The default is
    FALSE.

    \sa setAutoDelete()
*/

/*!
    \fn void Q3PtrQueue::setAutoDelete( bool enable )

    Sets the queue to auto-delete its contents if \a enable is TRUE
    and not to delete them if \a enable is FALSE.

    If auto-deleting is turned on, all the items in a queue are
    deleted when the queue itself is deleted. This can be quite
    convenient if the queue has the only pointer to the items.
    
    The default setting is FALSE, for safety. If you turn it on, be
    careful about copying the queue: you might find yourself with two
    queues deleting the same items.

    \sa autoDelete()
*/

/*!
    \fn QDataStream& Q3PtrQueue::read( QDataStream& s,
					Q3PtrCollection::Item& item )

    Reads a queue item, \a item, from the stream \a s and returns a
    reference to the stream.

    The default implementation sets \a item to 0.

    \sa write()
*/

/*!
    \fn QDataStream& Q3PtrQueue::write( QDataStream& s,
					Q3PtrCollection::Item item ) const

    Writes a queue item, \a item, to the stream \a s and returns a
    reference to the stream.

    The default implementation does nothing.

    \sa read()
*/
