/* -*- c++ -*- */

/*

 * Copyright 2007,2008 Free Software Foundation, Inc.

 * 

 * This file is part of GNU Radio

 * 

 * GNU Radio 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; either version 3, or (at your option)

 * any later version.

 * 

 * GNU Radio 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.

 */

#ifndef INCLUDED_MB_MSG_QUEUE_H

#define INCLUDED_MB_MSG_QUEUE_H

#include <mblock/common.h>

#include <gnuradio/omnithread.h>

#include <mblock/time.h>

/*!

 * \brief priority queue for mblock messages

 */

class mb_msg_queue : boost::noncopyable

{

  // When empty both head and tail are zero.

  struct subq {

    mb_message_sptr        head;

    mb_message_sptr        tail;

    bool empty_p() const { return head == 0; }

  };

  omni_mutex         d_mutex;

  omni_condition d_not_empty;        // reader waits on this

  // FIXME add bitmap to indicate which queues are non-empty.

  subq                 d_queue[MB_NPRI];

  mb_message_sptr get_highest_pri_msg_helper();

public:

  mb_msg_queue();

  ~mb_msg_queue();

  //! Insert \p msg into priority queue.

  void insert(mb_message_sptr msg);

  /*

   * \brief Delete highest pri message from the queue and return it.

   * Returns equivalent of zero pointer if queue is empty.

   */

  mb_message_sptr get_highest_pri_msg_nowait();

  /*

   * \brief Delete highest pri message from the queue and return it.

   * If the queue is empty, this call blocks until it can return a message.

   */

  mb_message_sptr get_highest_pri_msg();

  /*

   * \brief Delete highest pri message from the queue and return it.

   * If the queue is empty, this call blocks until it can return a message

   * or real-time exceeds the absolute time, abs_time.

   *

   * \param abs_time specifies the latest absolute time to wait until.

   * \sa mb_time::time

   *

   * \returns a valid mb_message_sptr, or the equivalent of a zero pointer

   * if the call timed out while waiting.

   */

  mb_message_sptr get_highest_pri_msg_timedwait(const mb_time &abs_time);

};

#endif /* INCLUDED_MB_MSG_QUEUE_H */