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

/*

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

 */

#include "ns3/log.h"

#include "msdu-aggregator.h"

#include "wifi-mac-header.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("MsduAggregator");

NS_OBJECT_ENSURE_REGISTERED (MsduAggregator);

TypeId

MsduAggregator::GetTypeId (void)

{

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

    .SetParent<Object> ()

    .SetGroupName ("Wifi")

  ;

  return tid;

}

MsduAggregator::DeaggregatedMsdus

MsduAggregator::Deaggregate (Ptr<Packet> aggregatedPacket)

{

  NS_LOG_FUNCTION_NOARGS ();

  DeaggregatedMsdus set;

  AmsduSubframeHeader hdr;

  Ptr<Packet> extractedMsdu = Create<Packet> ();

  uint32_t maxSize = aggregatedPacket->GetSize ();

  uint16_t extractedLength;

  uint32_t padding;

  uint32_t deserialized = 0;

  while (deserialized < maxSize)

    {

      deserialized += aggregatedPacket->RemoveHeader (hdr);

      extractedLength = hdr.GetLength ();

      extractedMsdu = aggregatedPacket->CreateFragment (0, static_cast<uint32_t> (extractedLength));

      aggregatedPacket->RemoveAtStart (extractedLength);

      deserialized += extractedLength;

      padding = (4 - ((extractedLength + 14) % 4 )) % 4;

      if (padding > 0 && deserialized < maxSize)

        {

          aggregatedPacket->RemoveAtStart (padding);

          deserialized += padding;

        }

      std::pair<Ptr<Packet>, AmsduSubframeHeader> packetHdr (extractedMsdu, hdr);

      set.push_back (packetHdr);

    }

  NS_LOG_INFO ("Deaggreated A-MSDU: extracted " << set.size () << " MSDUs");

  return set;

}

} //namespace ns3