source: source/ariba/communication/modules/transport/protlib/fqueue.h@ 4987

/// ----------------------------------------*- mode: C++; -*--

/// @file fqueue.h

/// a wrapper class for fastqueue C implementation

/// ----------------------------------------------------------

/// $Id: fqueue.h 2549 2007-04-02 22:17:37Z bless $

/// $HeadURL: https://svn.ipv6.tm.uka.de/nsis/protlib/trunk/include/fqueue.h $

// ===========================================================

//                      

// Copyright (C) 2005-2007, all rights reserved by

// - Institute of Telematics, Universitaet Karlsruhe (TH)

//

// More information and contact:

// https://projekte.tm.uka.de/trac/NSIS

//                      

// This program is free software; you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation; version 2 of the License

//

// This program is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License along

// with this program; if not, write to the Free Software Foundation, Inc.,

// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

//

// ===========================================================



/** @ingroup fastqueue

 *

 */



#ifndef __FQUEUE_H__

#define __FQUEUE_H__



#include <string>



#include "protlib_types.h"

#include "messages.h"



extern "C" {

#include"fastqueue.h"

}



namespace protlib {



/** @addtogroup fastqueue Fast Queue

 * @{

 */



// declared in messages.h

class message;





/** 

 * A fast message queue.

 *

 * This is a fast and thread-safe message queue with expedited data

 * support. It is an object oriented wrapper around fastqueue.c.

 * The queue grows dynamically and has no built-in entry limit.

 */

class FastQueue {

public:

        /// FastQueue error

        class FQError{};

        /// constructor

        FastQueue(const char *qname = 0, bool exp = false);

        /// destructor

        ~FastQueue();

        /// enqueue message

        bool enqueue(message *element, bool exp = false);

        /// dequeue message

        message *dequeue(bool blocking = true);

        /// dequeue message, timed wait

        message *dequeue_timedwait(const struct timespec &tspec);

        /// dequeue message, timed wait

        message *dequeue_timedwait(const long int msec);

        /// is queue empty

        bool is_empty() const;

        /// get number of enqueued messages

        unsigned long size() const;

        /// is expedited data support enabled

        bool is_expedited_enabled() const;

        /// enable/disable expedited data

        bool enable_expedited(bool exp);

        /// shutdown queue, do not accept messages

        void shutdown();

        /// delete stored messages

        unsigned long cleanup();

        /// Return the name of the queue.

        const char* get_name() const { return queue_name.c_str(); }

private:

        /// C fastqueue

        queue_t *queue;

        /// name of the queue, also stored in the queue_t

        string queue_name;

        /// accept or reject messages

        bool shutdownflag;

};





/**

 * Remove the first message from the queue.

 *

 * Messages are removed in the same order they were added to the queue (FIFO).

 * If the expedited messages feature is enabled, there's an exception to

 * this rule: Expedited messages are always removed before all other messages.

 * The FIFO condition still holds among expedited messages, however.

 *

 * If blocking is set, wait infinitely for a message. If set to false,

 * return immediately if the queue is empty. In this case, NULL is returned.

 *

 * @param blocking if true, block until a message arrives

 *

 * @return the message, or NULL

 */

inline

message *

FastQueue::dequeue(bool blocking)

{

  return static_cast<message*>(blocking ? 

                               dequeue_element_wait(queue) :

                               dequeue_element_nonblocking(queue));

}





/**

 * Wait for a message for a given time.

 *

 * If no message arrives in the given time period, NULL is returned.

 *

 * @param tspec the time to wait

 *

 * @return the message, or NULL

 */

inline

message *

FastQueue::dequeue_timedwait(const struct timespec& tspec)

{

  return (message*)dequeue_element_timedwait(queue, &tspec);

}



//@}



} // end namespace protlib



#endif