/* -*-  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"

NS_LOG_COMPONENT_DEFINE ("MsduAggregator");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (MsduAggregator);

TypeId

MsduAggregator::GetTypeId (void)

{

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

    .SetParent<Object> ()

    ;

  return tid;

}

MsduAggregator::DeaggregatedMsdus

MsduAggregator::Deaggregate (Ptr<Packet> aggregatedPacket)

{

  NS_LOG_FUNCTION_NOARGS ();

  DeaggregatedMsdus set;

  AmsduSubframeHeader hdr;

  uint32_t maxSize = aggregatedPacket->GetSize ();

  // The worst condition is: two aggregated packets with no padding.

  // 28 bytes is the size of two Amsdu subframe headers.

  uint8_t *buffer = new uint8_t[maxSize-28];

  uint32_t padding;

  uint32_t deserialized = 0;

  while (deserialized < maxSize)

   {

     deserialized += aggregatedPacket->RemoveHeader (hdr);

     deserialized += aggregatedPacket->CopyData (buffer, hdr.GetLength ());

     aggregatedPacket->RemoveAtStart (hdr.GetLength ());

     padding = (4 - ((hdr.GetLength () + 14) %4 )) % 4;

     if (padding > 0)

       {

         aggregatedPacket->RemoveAtStart (padding);

         deserialized += padding;

       }

     //a new packet is created with the content of extracted msdu

     Ptr<Packet> p = Create<Packet> (buffer, hdr.GetLength ());

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

     set.push_back (packetHdr);

   }

  delete [] buffer;

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

  return set;

}

} //namespace ns3