1 /*

     2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:   Declaration of the RWlanLddCircularBuffer class.

    15 *

    16 */

    17 

    18 /*

    19 * %version: 2 %

    20 */

    21 

    22 #ifndef R_WLANCIRCULARBUFFER_H

    23 #define R_WLANCIRCULARBUFFER_H

    24 

    25 class TDataBuffer;

    26 

    27 /**

    28  * Wlan LDD Shared Memory FIFO queue for Tx packets.

    29  * 

    30  * @param size The size of the queue in packets.

    31  */

    32 template <TUint size>

    33 class RWlanCircularBuffer

    34     {

    35 public:

    36 

    37     /* Because this class is mapped into shared memory, it does not have

    38      * a constructor or a desctructor.

    39      */ 

    40 

    41     /**

    42      * Initialization. This method acts as a contructor.

    43      */ 

    44     inline void DoInit();

    45 

    46     /**

    47      * Release. This method acts as a desctructor.

    48      */ 

    49     inline void Release();

    50     

    51     /**

    52      * This method returns and removes the next packet from the queue.

    53      * 

    54      * @return Pointer to the meta header attached to the packet on success.

    55      *         NULL if the queue is empty.

    56      */ 

    57     inline TDataBuffer* GetPacket();

    58    

    59     /**

    60      * This method is used to put a packet to the end of the queue.

    61      * 

    62      * @param aPacket Pointer to the meta header attached to the packet.

    63      * @return ETrue if the Packet was added to the queue.

    64      *         EFalse if the queue was already full and the Packet could not

    65      *         be added to the queue.

    66      */ 

    67     inline TBool PutPacket( TDataBuffer* aPacket );

    68     

    69     /**

    70      * Returns the next packet in the queue without removing it from the queue.

    71      * 

    72      * @return Pointer to the meta header attached to the packet on the top 

    73      *         of the queue.

    74      */

    75     inline TDataBuffer* PeekPacket();

    76 

    77     /**

    78      * Returns the number of packets in the queue.

    79      * 

    80      * @return number of packets in the queue.

    81      */

    82     inline TUint GetLength() const;

    83     

    84     /**

    85      * This method can be used to check if the queue is empty.

    86      * 

    87      * @return ETrue, when the queue is empty.

    88      *         EFalse, when the queue is not empty.

    89      */ 

    90     inline TBool IsEmpty() const;

    91 

    92     /**

    93      * This method can be used to check if the queue is full.

    94      * 

    95      * @return ETrue, when the queue is full.

    96      *         EFalse, when the queue is not full.

    97      */ 

    98     inline TBool IsFull() const ;

    99     

   100     /**

   101      * This method can be used to check if the queue is active.

   102      * 

   103      * @param aTimeNow Current time as microseconds since midnight, January 

   104      *        1st, 0 AD nominal Gregorian

   105      * @return ETrue, if the queue is active.

   106      *         EFalse, if the queue is not active.

   107      */ 

   108     inline TBool IsActive( TInt64 aTimeNow ) const;

   109     

   110 private:    // Data

   111     

   112     /** Queue as a circular buffer */

   113     TDataBuffer* iBuffer[size];

   114     

   115     /** Index of the packet to get next. See GetPacket() */

   116     TUint iGetIndex;

   117     

   118     /** Index where to put the next packet. See PutPacket() */

   119     TUint iPutIndex;

   120     

   121     /** The number of packets currently in the queue */

   122     TUint iPacketAmount;

   123    

   124     /** The capacity of the queue */

   125     TUint iSize;

   126     

   127     /** 

   128     * Time stamp (as microseconds since midnight, January 1st, 0 AD nominal

   129     * Gregorian) when the queue became empty. 

   130     * Valid only if the queue is empty 

   131     */

   132     TInt64 iBecameEmptyAt;

   133 };

   134 

   135 #ifdef __KERNEL_MODE__

   136 

   137 #include "wllddcircularbuffer.inl"

   138 

   139 #endif

   140 

   141 #endif /* R_WLANCIRCULARBUFFER_H */