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

//

// Copyright (c) 2006 Georgia Tech Research Corporation

//

// 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: Rajib Bhattacharjea<raj.b@gatech.edu>

//

// Georgia Tech Network Simulator - Data Descriptors

// George F. Riley.  Georgia Tech, Spring 2002

#ifndef PENDING_DATA_H

#define PENDING_DATA_H

#include "ns3/packet.h"

#include "pending-data.h"

#include "ns3/sequence-number.h"

#include "ns3/ptr.h"

namespace ns3

{

class Packet;

/**

 * \ingroup tcp

 *

 * \brief class for managing I/O between applications and TCP

 */

class PendingData {

public:

  PendingData ();

  /**

   * Constructor

   * \param s size

   * \param d data

   * \param msg message size

   * \param resp response size

   */

  PendingData (uint32_t s, uint8_t* d = NULL, uint32_t msg = 0, uint32_t resp = 0);

  /**

   * Constructor from string

   * \param s string

   */

  PendingData (const std::string& s); // Construct from string

  /**

   * Copy constructor

   * \param o object to copy

   */

  PendingData (const PendingData& o);   // Copy constructor

  virtual ~PendingData ();     // Destructor

  /**

   * Returns the size of the pending data

   * \returns size of pending data

   */

  uint32_t Size () const { return size; }

  /**

   * \brief Remove all associated data

   */

  virtual void Clear ();

  /**

   * \brief Add some data to end

   * \param s the data size.

   * \param d the data to store.

   */

  virtual void Add (uint32_t s, const uint8_t* d = 0); //

  /**

   * \brief Add some data to end

   * \param p packet containing the data.

   */

  virtual void Add (Ptr<Packet> p);

  /**

   * This method returns the number of bytes in the PendingData buffer

   * beyond the sequence number specified by seqOffset.

   *

   * The variables seqFront and seqOffset correspond to a sequence number

   * space in use by the user.  What is significant in this method is the

   * difference between them; i.e. the quantity (seqOffset - seqFront). 

   * This difference is subtracted from Size(), yielding the number of

   * bytes beyond seqOffset, from the user perspective, in the PendingData

   * buffer.

   *

   * If the first number specified is not a sequence number that corresponds

   * to the first data byte in the PendingData buffer, the computation

   * returned will be in error.

   * 

   * \return number of bytes 

   * \param seqFront sequence number of assumed first byte in the PendingData

   * \param seqOffset sequence number of offset 

   */

  virtual uint32_t SizeFromSeq (const SequenceNumber32& seqFront, const SequenceNumber32& seqOffset);

  // Inquire available data from offset

  /**

   * \return number of bytes in the data buffer beyond the offset specified

   * \param offset offset (from zero) 

   */

  virtual uint32_t SizeFromOffset (uint32_t offset);

  // Available size from sequence difference 

  /**

   * Subtracts seqFront from seqOffset after enforcing seqFront is less

   * than seqOffset

   *

   * \param seqFront sequence number to be subtracted from seqOffset

   * \param seqOffset higher sequence number

   * \return seqOffset-seqFront

   */

  virtual uint32_t OffsetFromSeq (const SequenceNumber32& seqFront, const SequenceNumber32& seqOffset);

  /**

   * \brief Copy data starting from a give offset

   * \param s size of data to copy

   * \param o offset

   * \returns a packet containing the requested data

   */

  virtual Ptr<Packet> CopyFromOffset  (uint32_t s, uint32_t o);  // Size, offset, ret packet

  /**

   * \brief Copy data starting from a give offset

   * \param s size of data to copy

   * \param f Front sequence

   * \param o Offset sequence

   *

   * \see PendingData::OffsetFromSeq()

   * \returns a packet containing the requested data

   */

  virtual Ptr<Packet> CopyFromSeq (uint32_t s, const SequenceNumber32& f, const SequenceNumber32& o);

  /**

   * Permits object to clear any pending data between seqFront and 

   * seqOffset - 1).  Callers should check the return value to determine

   * whether any data was removed from the front.

   *

   * \param seqFront sequence number to start to try to remove from 

   * \param seqOffset first sequence number in buffer that should be retained

   * \return number of bytes from the front that were removed from the buffer

   */

  virtual uint32_t RemoveToSeq (const SequenceNumber32& seqFront, const SequenceNumber32& seqOffset);

  /**

   * \brief Create a copy of self

   * \returns copy of pending data

   */

  PendingData*   Copy () const;

  /**

   * \brief Create a copy of self with new size

   *

   * Assumes no associated data

   * \param s new size

   * \returns copy of pending data

   */

  PendingData*   CopyS (uint32_t s);         // Copy

  /**

   * \brief Create a copy of self with new size, new data

   *

   * Assumes no associated data

   * \param s new size

   * \param d new data

   * \returns copy of pending data

   */

  PendingData*   CopySD (uint32_t s, uint8_t* d);

public:

  uint32_t size;        //!< Number of data bytes

  std::vector<Ptr<Packet> > data;         //!< Corresponding data (may be null)

  // The next two fields allow simulated applications to exchange some info

  uint32_t msgSize;     //!< Total size of message

  uint32_t responseSize; //!< Size of response requested

};

} //namepsace ns3

#endif /* PENDING_DATA_H */