cpqueue.h
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上传日期:2007-06-06
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- /* ***** BEGIN LICENSE BLOCK *****
- * Version: RCSL 1.0/RPSL 1.0
- *
- * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved.
- *
- * The contents of this file, and the files included with this file, are
- * subject to the current version of the RealNetworks Public Source License
- * Version 1.0 (the "RPSL") available at
- * http://www.helixcommunity.org/content/rpsl unless you have licensed
- * the file under the RealNetworks Community Source License Version 1.0
- * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl,
- * in which case the RCSL will apply. You may also obtain the license terms
- * directly from RealNetworks. You may not use this file except in
- * compliance with the RPSL or, if you have a valid RCSL with RealNetworks
- * applicable to this file, the RCSL. Please see the applicable RPSL or
- * RCSL for the rights, obligations and limitations governing use of the
- * contents of the file.
- *
- * This file is part of the Helix DNA Technology. RealNetworks is the
- * developer of the Original Code and owns the copyrights in the portions
- * it created.
- *
- * This file, and the files included with this file, is distributed and made
- * available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- *
- * Technology Compatibility Kit Test Suite(s) Location:
- * http://www.helixcommunity.org/content/tck
- *
- * Contributor(s):
- *
- * ***** END LICENSE BLOCK ***** */
- /*******************************************************************
- *
- * NAME: CPQueue.h
- *
- * CLASS:
- * CPtrQueue class declaration.
- *
- * DESCRIPTION:
- * Class declaration for a 'Queue of pointers' object.
- * This object inherits from the CByteQueue object by
- * overriding the GetElementSize() method, and
- * defining it's own assignemt operator.
- *
- * NOTES (from CByteQueue):
- * The only time a subclass MUST provide a virtual override
- * is for the GetElementSize() method when the subclass changes
- * the size of queued elements. All other virtual methods
- * provide fully functional default behavior that will ramain
- * functional even when the ElementSize changes.
- *
- * The assignment operator is one of the few cases where a
- * subclass will need to provide new functionality by virtue of
- * inheriting from the base. Subclasses should use the base
- * method for assigning the bits of the base class prior to
- * performing their own assignment related operations.
- *
- *******************************************************************/
-
- #if !defined( _CPQUEUE_H )
- #define _CPQUEUE_H
- #include "cbqueue.h"
- class CPtrQueue : public CByteQueue
- {
- public:
- /*
- * These are the functions we NEED to implement to get the
- * desired functionality out of our base class CByteQueue.
- */
- /*
- ** CPtrQueue( nMaxPtrs )
- *
- * PARAMETERS:
- * nMaxPtrs The maximum number of pointers we want to be able
- * to enqueue.
- *
- * DESCRIPTION:
- * Parameterized constructor.
- * This is the primary means of constructing a Pointer Queue.
- *
- * RETURNS:
- * void
- */
- CPtrQueue( UINT16 nMaxPtrs ) :
- CByteQueue( nMaxPtrs * sizeof( void * ), sizeof( void * ) )
- {
- // Deliberately empty
- }
-
- /*
- ** UINT16 GetElementSize()
- *
- * PARAMETERS:
- * void
- *
- * DESCRIPTION:
- * Returns the size of one of our queue elements.
- * In this case it's the size of a pointer.
- *
- * RETURNS:
- * The size of a queue element.
- */
- virtual UINT16 GetElementSize() const
- {
- return( sizeof( void * ) );
- }
- /*
- ** CPtrQueue &operator=( rReferent )
- *
- * PARAMETERS:
- * Constant reference to a queue we want to copy.
- *
- * DESCRIPTION:
- * Custom assignment operator allows us to assign Queues.
- *
- * RETURNS:
- * A reference to the queue we've assigned into.
- */
- CPtrQueue &operator=( const CPtrQueue &rReferent )
- {
- // return( CByteQueue::operator=( rReferent ) );
- this->CByteQueue::operator=( rReferent );
- return( *this );
- }
- /*
- * These are the functions we've added to provide
- * some of the semantics that are in the problem
- * domain of a queue of pointers.
- */
- /*
- ** UINT16 EnQueuePtr( pPtr )
- *
- * PARAMETERS:
- * A pointer we want to enqueue.
- *
- * DESCRIPTION:
- * Takes the value assigned to pPtr and enqueues it.
- *
- * RETURNS:
- * The number of bytes we put into the queue.
- */
- UINT16 EnQueuePtr( void *pPtr )
- {
- return( Base_EnQueueBytes( &pPtr, sizeof( pPtr ) ) );
- }
- /*
- ** void *DeQueuePtr( BOOL &bIsValid )
- *
- * PARAMETERS:
- * A reference to a boolean flag indicating if the return is valid.
- *
- * DESCRIPTION:
- * Dequeues the head pointer element in the queue.
- *
- * RETURNS:
- * The value of the head pointer element we've dequeue'd.
- */
- void *DeQueuePtr( BOOL &bIsValid )
- {
- UINT16 iWrote;
- void *pPtr;
- iWrote = Base_DeQueueBytes( &pPtr, sizeof( pPtr ) );
- if (iWrote)
- {
- bIsValid = TRUE;
- return( pPtr );
- }
- else
- {
- bIsValid = FALSE;
- return( NULL );
- }
- }
- /*
- ** void *PeekPtrAt( nIndex, BOOL &bIsValid )
- *
- * PARAMETERS:
- * nIndex The index of the element off of the head
- * queue element we want to peek at.
- *
- * DESCRIPTION:
- * Peeks at an element offset from the queue head.
- *
- * RETURNS:
- * The value of the pointer element we're peeking at
- * (if it's a valid element).
- * bIsValid is set to true or false to indicate the
- * validity of the return value.
- * (since a NULL pointer might be a valid queue entry.
- */
- void *PeekPtrAt( UINT16 nIndex, BOOL &bIsValid )
- {
- UINT16 iCount;
- void *pPtr;
- iCount = PeekAt( nIndex, &pPtr );
- if (iCount)
- {
- bIsValid = TRUE;
- return( pPtr );
- }
- else
- {
- bIsValid = FALSE;
- return( NULL );
- }
- }
- };
- #endif // !defined( _CPQUEUE_H )