/* -*- c++ -*- */
/*
 * Copyright 2009 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gruel/msg_queue.h>
#include <stdexcept>

using namespace pmt;

namespace gruel {

  msg_queue_sptr
  make_msg_queue(unsigned int limit)
  {
    return msg_queue_sptr(new msg_queue(limit));
  }
  
  msg_queue::msg_queue(unsigned int limit)
    : d_limit(limit)
  {
  }
  
  msg_queue::~msg_queue()
  {
    flush();
  }

  void
  msg_queue::insert_tail(pmt_t msg)
  {
    gruel::scoped_lock guard(d_mutex);

    while (full_p())
      d_not_full.wait(guard);

    d_msgs.push_back(msg);
    d_not_empty.notify_one();
  }

  pmt_t
  msg_queue::delete_head()
  {
    gruel::scoped_lock guard(d_mutex);

    while (empty_p())
      d_not_empty.wait(guard);

    pmt_t m(d_msgs.front());
    d_msgs.pop_front();

    if (d_limit > 0)		// Unlimited length queues never block on write
      d_not_full.notify_one();

    return m;
  }

  pmt_t
  msg_queue::delete_head_nowait()
  {
    gruel::scoped_lock guard(d_mutex);

    if (empty_p())
      return pmt_t();
	
    pmt_t m(d_msgs.front());
    d_msgs.pop_front();

    if (d_limit > 0)		// Unlimited length queues never block on write
      d_not_full.notify_one();

    return m;
  }

  void
  msg_queue::flush()
  {
    while (delete_head_nowait() != pmt_t())
      ;
  }

} /* namespace gruel */