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

/*

 * Copyright (c) 2005 INRIA

 *

 * 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>

 */

#ifndef TRAILER_H

#define TRAILER_H

#include "chunk.h"

#include "buffer.h"

#include <stdint.h>

namespace ns3 {

/**

 * \ingroup packet

 *

 * \brief Protocol trailer serialization and deserialization.

 *

 * Every Protocol trailer which needs to be inserted or removed

 * from a Packet instance must derive from this base class and

 * implement the pure virtual methods defined here.

 */

class Trailer : public Chunk

{

public:

  static TypeId GetTypeId (void);

  virtual ~Trailer ();

  /**

   * \returns the expected size of the trailer.

   *

   * This method is used by Packet::AddTrailer

   * to store a trailer into the byte buffer of a packet. This method

   * should return the number of bytes which are needed to store

   * the full trailer data by Serialize.

   */

  virtual uint32_t GetSerializedSize (void) const = 0;

  /**

   * \param start an iterator which points to where the trailer

   *        should be written.

   *

   * This method is used by Packet::AddTrailer to

   * store a header into the byte buffer of a packet.

   * The data written is expected to match bit-for-bit the 

   * representation of this trailer in real networks.

   * The input iterator points to the end of the area where the 

   * data shall be written. This method is thus expected to call

   * Buffer::Iterator::Prev prior to actually writing any data.

   */

  virtual void Serialize (Buffer::Iterator start) const = 0;

  /**

   * \param end an iterator which points to the end of the buffer

   *        where the trailer should be read from.

   * \returns the number of bytes read.

   *

   * This method is used by Packet::RemoveTrailer to

   * re-create a trailer from the byte buffer of a packet. 

   * The data read is expected to match bit-for-bit the 

   * representation of this trailer in real networks.

   * The input iterator points to the end of the area where the 

   * data shall be written. This method is thus expected to call

   * Buffer::Iterator::Prev prio to actually reading any data.

   */

  virtual uint32_t Deserialize (Buffer::Iterator end) = 0;

  /**

   * This method is used by Packet::Print to print the 

   * content of a trailer as ascii data to a c++ output stream.

   * Although the trailer is free to format its output as it

   * wishes, it is recommended to follow a few rules to integrate

   * with the packet pretty printer: start with flags, small field 

   * values located between a pair of parens. Values should be separated 

   * by whitespace. Follow the parens with the important fields, 

   * separated by whitespace.

   * i.e.: (field1 val1 field2 val2 field3 val3) field4 val4 field5 val5

   */

  virtual void Print (std::ostream &os) const = 0;

};

std::ostream & operator << (std::ostream &os, const Trailer &trailer);

} // namespace ns3

#endif /* TRAILER_H */