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

/*

 * Copyright (c) 2006 INRIA

 * All rights reserved.

 *

 * 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 TAGS_H

#define TAGS_H

#include <stdint.h>

#include <ostream>

#include <vector>

namespace ns3 {

template <typename T>

class TagPrettyPrinter;

/**

 * \ingroup constants

 * \brief Tag maximum size

 * The maximum size (in bytes) of a Tag is stored

 * in this constant.

 */

#define TAGS_MAX_SIZE 16

class Tags {

public:

  inline Tags ();

  inline Tags (Tags const &o);

  inline Tags &operator = (Tags const &o);

  inline ~Tags ();

  template <typename T>

  void Add (T const&tag);

  template <typename T>

  bool Remove (T &tag);

  template <typename T>

  bool Peek (T &tag) const;

  void PrettyPrint (std::ostream &os);

  inline void RemoveAll (void);

  enum {

      SIZE = TAGS_MAX_SIZE

  };

private:

  struct TagData {

      struct TagData *m_next;

      uint32_t m_id;

      uint32_t m_count;

      uint8_t m_data[Tags::SIZE];

  };

  bool Remove (uint32_t id);

  struct Tags::TagData *AllocData (void);

  void FreeData (struct TagData *data);

  static struct Tags::TagData *gFree;

  static uint32_t gN_free;

  struct TagData *m_next;

};

/**

 * \brief pretty print packet tags

 * 

 * This class is used to register a pretty-printer

 * callback function to print in a nice user-friendly

 * way the content of the target type. To register

 * such a type, all you need to do is instantiate

 * an instance of this type as a static variable.

 */

template <typename T>

class TagRegistration {

public:

  /**

   * \param uuid a uuid generated with uuidgen

   * \param fn a function which can pretty-print an instance

   *        of type T in the output stream.

   */

  TagRegistration<T> (std::string uuid, void(*fn) (T const*, std::ostream &));

private:

  static void PrettyPrinterCb (uint8_t *buf, std::ostream &os);

  static void(*m_prettyPrinter) (T const*, std::ostream &);

};

}; // namespace ns3

/**************************************************************

   An implementation of the templates defined above

 *************************************************************/

#include <string>

namespace ns3 {

class TagRegistry {

public:

  typedef void (*PrettyPrinter) (uint8_t [Tags::SIZE], std::ostream &);

  static void Record (std::string uuid, PrettyPrinter prettyPrinter);

  /**

   * returns a numeric integer which uniquely identifies the input string.

   * that integer cannot be zero which is a reserved value.

   */

  static uint32_t LookupUid (std::string uuid);

  static void PrettyPrint (uint32_t uid, uint8_t buf[Tags::SIZE], std::ostream &os);

private:

  typedef std::vector<std::pair<std::string,PrettyPrinter> > TagsData;

  typedef std::vector<std::pair<std::string,PrettyPrinter> >::const_iterator TagsDataCI;

  static bool m_sorted;

  static TagsData m_registry;

};

/**

 * The TypeUid class is used to create a mapping Type --> uid

 * Note that we use a static getUuid function which contains a

 * static std::string variable rather than a simpler static

 * member std::string variable to ensure the proper order

 * of initialization when these methods are invoked

 * from the constructor of another static variable.

 */

template <typename T>

class TypeUid {

public:

  static void Record (std::string uuid);

  static const uint32_t GetUid (void);

private:

  static std::string *GetUuid (void);

  T m_realType;

};

template <typename T>

void TypeUid<T>::Record (std::string uuid)

{

  *(GetUuid ()) = uuid;

}

template <typename T>

const uint32_t TypeUid<T>::GetUid (void)

{

  static const uint32_t uid = TagRegistry::LookupUid (*(GetUuid ()));

  return uid;

}

template <typename T>

std::string *TypeUid<T>::GetUuid (void)

{

  static std::string uuid;

  return &uuid;

}

/**

 * Implementation of the TagRegistration registration class.

 * It records a callback with the TagRegistry

 * This callback performs type conversion before forwarding

 * the call to the user-provided function.

 */

template <typename T>

TagRegistration<T>::TagRegistration (std::string uuid, void (*prettyPrinter) (T const*, std::ostream &))

{

  m_prettyPrinter  = prettyPrinter;

  TagRegistry::Record (uuid, &TagRegistration<T>::PrettyPrinterCb);

  TypeUid<T>::Record (uuid);

}

template <typename T>

void 

TagRegistration<T>::PrettyPrinterCb (uint8_t *buf, std::ostream &os)

{

  T *tag = reinterpret_cast<T *> (buf);

  (*m_prettyPrinter) (tag, os);

}

template <typename T>

void (*TagRegistration<T>::m_prettyPrinter) (T const*, std::ostream &) = 0;

template <typename T>

void 

Tags::Add (T const&tag)

{

  uint8_t const*buf = reinterpret_cast<uint8_t const*> (&tag);

  // ensure this id was not yet added

  for (struct TagData *cur = m_next; cur != 0; cur = cur->m_next) 

    {

    }

  struct TagData *newStart = AllocData ();

  newStart->m_count = 1;

  newStart->m_next = 0;

  newStart->m_id = TypeUid<T>::GetUid ();

  memcpy (newStart->m_data, buf, sizeof (T));

  newStart->m_next = m_next;

  m_next = newStart;

}

template <typename T>

bool

Tags::Remove (T &tag)

{

  return Remove (TypeUid<T>::GetUid ());

}

template <typename T>

bool

Tags::Peek (T &tag) const

{

  uint8_t *buf = reinterpret_cast<uint8_t *> (&tag);

  for (struct TagData *cur = m_next; cur != 0; cur = cur->m_next) 

    {

      if (cur->m_id == TypeUid<T>::GetUid ()) 

        {

          /* found tag */

          memcpy (buf, cur->m_data, sizeof (T));

          return true;

        }

    }

  /* no tag found */

  return false;

}

Tags::Tags ()

  : m_next ()

{}

Tags::Tags (Tags const &o)

  : m_next (o.m_next)

{

  if (m_next != 0) 

    {

      m_next->m_count++;

    }

}

Tags &

Tags::operator = (Tags const &o)

{

  // self assignment

  if (m_next == o.m_next) 

    {

      return *this;

    }

  RemoveAll ();

  m_next = o.m_next;

  if (m_next != 0) 

    {

      m_next->m_count++;

    }

  return *this;

}

Tags::~Tags ()

{

  RemoveAll ();

}

void

Tags::RemoveAll (void)

{

  struct TagData *prev = 0;

  for (struct TagData *cur = m_next; cur != 0; cur = cur->m_next) 

    {

      cur->m_count--;

      if (cur->m_count > 0) 

        {

          break;

        }

      if (prev != 0) 

        {

          FreeData (prev);

        }

      prev = cur;

    }

  if (prev != 0) 

    {

      FreeData (prev);

    }

  m_next = 0;

}

}; // namespace ns3

#endif /* TAGS_H */