/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2005, 2009 INRIA

 * Copyright (c) 2009 MIRKO BANCHI

 *

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

 * it under the terms of the GNU General Public License version 2 as 

 * published by the Free Software Foundation;

 *

 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 * Author: Mirko Banchi <mk.banchi@gmail.com>

 */

#include "ns3/simulator.h"

#include "ns3/packet.h"

#include "ns3/uinteger.h"

#include "wifi-mac-queue.h"

using namespace std;

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (WifiMacQueue);

WifiMacQueue::Item::Item (Ptr<const Packet> packet, 

                          const WifiMacHeader &hdr, 

                          Time tstamp)

  : packet (packet), hdr (hdr), tstamp (tstamp)

{}

TypeId 

WifiMacQueue::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::WifiMacQueue")

    .SetParent<Object> ()

    .AddConstructor<WifiMacQueue> ()

    .AddAttribute ("MaxPacketNumber", "If a packet arrives when there are already this number of packets, it is dropped.",

                   UintegerValue (400),

                   MakeUintegerAccessor (&WifiMacQueue::m_maxSize),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("MaxDelay", "If a packet stays longer than this delay in the queue, it is dropped.",

                   TimeValue (Seconds (10.0)),

                   MakeTimeAccessor (&WifiMacQueue::m_maxDelay),

                   MakeTimeChecker ())

    ;

  return tid;

}

WifiMacQueue::WifiMacQueue ()

  : m_size (0)

{}

WifiMacQueue::~WifiMacQueue ()

{

  Flush ();

}

void 

WifiMacQueue::SetMaxSize (uint32_t maxSize)

{

  m_maxSize = maxSize;

}

void

WifiMacQueue::SetMaxDelay (Time delay)

{

  m_maxDelay = delay;

}

uint32_t 

WifiMacQueue::GetMaxSize (void) const

{

  return m_maxSize;

}

Time 

WifiMacQueue::GetMaxDelay (void) const

{

  return m_maxDelay;

}

void 

WifiMacQueue::Enqueue (Ptr<const Packet> packet, const WifiMacHeader &hdr)

{

  Cleanup ();

  if (m_size == m_maxSize) 

    {

      return;

    }

  Time now = Simulator::Now ();

  m_queue.push_back (Item (packet, hdr, now));

  m_size++;

}

void

WifiMacQueue::Cleanup (void)

{

  if (m_queue.empty ()) 

    {

      return;

    }

  Time now = Simulator::Now ();

  uint32_t n = 0;

  for (PacketQueueI i = m_queue.begin (); i != m_queue.end ();) 

    {

      if (i->tstamp + m_maxDelay > now) 

        {

          i++;

        }

      else

        {

          i = m_queue.erase (i);

          n++;

        }

    }

  m_size -= n;

}

Ptr<const Packet>

WifiMacQueue::Dequeue (WifiMacHeader *hdr)

{

  Cleanup ();

  if (!m_queue.empty ()) 

    {

      Item i = m_queue.front ();

      m_queue.pop_front ();

      m_size--;

      *hdr = i.hdr;

      return i.packet;

    }

  return 0;

}

Ptr<const Packet>

WifiMacQueue::Peek (WifiMacHeader *hdr)

{

  Cleanup ();

  if (!m_queue.empty ()) 

    {

      Item i = m_queue.front ();

      *hdr = i.hdr;

      return i.packet;

    }

  return 0;

}

Ptr<const Packet>

WifiMacQueue::DequeueByTidAndAddress (WifiMacHeader *hdr, uint8_t tid, 

                                      WifiMacHeader::AddressType type, Mac48Address dest)

{

  Cleanup ();

  Ptr<const Packet> packet = 0;

  if (!m_queue.empty ())

    {

      PacketQueueI it;

      NS_ASSERT (type <= 4);

      for (it = m_queue.begin (); it != m_queue.end (); ++it)

        {

          if (it->hdr.IsQosData ())

            {

              if (GetAddressForPacket (type, it) == dest &&

                  it->hdr.GetQosTid () == tid)

                {

                  packet = it->packet;

                  *hdr = it->hdr;

                  m_queue.erase (it);

                  m_size--;

                  break;

                }

            }

        }

    }

  return packet;

}

Ptr<const Packet>

WifiMacQueue::PeekByTidAndAddress (WifiMacHeader *hdr, uint8_t tid, 

                                   WifiMacHeader::AddressType type, Mac48Address dest)

{

  Cleanup ();

  if (!m_queue.empty ())

    {

      PacketQueueI it;

      NS_ASSERT (type <= 4);

      for (it = m_queue.begin (); it != m_queue.end (); ++it)

        {

          if (it->hdr.IsQosData ())

            {

              if (GetAddressForPacket (type, it) == dest &&

                  it->hdr.GetQosTid () == tid)

                {

                  *hdr = it->hdr;

                  return it->packet;

                }

            }

        }

    }

  return 0;

}

bool

WifiMacQueue::IsEmpty (void)

{

  Cleanup ();

  return m_queue.empty ();

}

uint32_t

WifiMacQueue::GetSize (void)

{

  return m_size;

}

void

WifiMacQueue::Flush (void)

{

  m_queue.erase (m_queue.begin (), m_queue.end ());

  m_size = 0;

}

Mac48Address

WifiMacQueue::GetAddressForPacket (enum WifiMacHeader::AddressType type, PacketQueueI it)

{

  if (type == WifiMacHeader::ADDR1)

    {

      return it->hdr.GetAddr1 ();

    }

  if (type == WifiMacHeader::ADDR2)

    {

      return it->hdr.GetAddr2 ();

    }

  if (type == WifiMacHeader::ADDR3)

    {

      return it->hdr.GetAddr3 ();

    }

  return 0;

}

bool

WifiMacQueue::Remove (Ptr<const Packet> packet)

{

  PacketQueueI it = m_queue.begin ();

  for (; it != m_queue.end (); it++)

    {

      if (it->packet == packet)

        {

          m_queue.erase (it);

          return true;

        }

    }

  return false;

}

void

WifiMacQueue::PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr)

{

  Cleanup ();

  if (m_size == m_maxSize)

    {

      return;

    }

  Time now = Simulator::Now ();

  m_queue.push_front (Item (packet, hdr, now));

  m_size++;

}

} // namespace ns3