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

/*

 * Copyright (c) 2006 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>

 */

#include "packet-tag-list.h"

#include "tag-buffer.h"

#include "tag.h"

#include "ns3/fatal-error.h"

#include "ns3/log.h"

#include <string.h>

NS_LOG_COMPONENT_DEFINE ("PacketTagList");

namespace ns3 {

#ifdef USE_FREE_LIST

struct PacketTagList::TagData *PacketTagList::g_free = 0;

uint32_t PacketTagList::g_nfree = 0;

struct PacketTagList::TagData *

PacketTagList::AllocData (void) const

{

  NS_LOG_FUNCTION (g_nfree);

  struct PacketTagList::TagData *retval;

  if (g_free != 0) 

    {

      retval = g_free;

      g_free = g_free->m_next;

      g_nfree--;

    } 

  else 

    {

      retval = new struct PacketTagList::TagData ();

    }

  return retval;

}

void

PacketTagList::FreeData (struct TagData *data) const

{

  NS_LOG_FUNCTION (g_nfree << data);

  if (g_nfree > 1000) 

    {

      delete data;

      return;

    }

  g_nfree++;

  data->next = g_free;

  data->tid = TypeId ();

  g_free = data;

}

#else

struct PacketTagList::TagData *

PacketTagList::AllocData (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  struct PacketTagList::TagData *retval;

  retval = new struct PacketTagList::TagData ();

  return retval;

}

void

PacketTagList::FreeData (struct TagData *data) const

{

  NS_LOG_FUNCTION (data);

  delete data;

}

#endif

bool

PacketTagList::Remove (Tag &tag)

{

  NS_LOG_FUNCTION (this << tag.GetInstanceTypeId ());

  TypeId tid = tag.GetInstanceTypeId ();

  bool found = false;

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

    {

      if (cur->tid == tid) 

        {

          found = true;

          tag.Deserialize (TagBuffer (cur->data, cur->data+PACKET_TAG_MAX_SIZE));

        }

    }

  if (!found) 

    {

      return false;

    }

  struct TagData *start = 0;

  struct TagData **prevNext = &start;

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

    {

      if (cur->tid == tid) 

        {

          /**

           * XXX

           * Note: I believe that we could optimize this to

           * avoid copying each TagData located after the target id

           * and just link the already-copied list to the next tag.

           */

          continue;

        }

      struct TagData *copy = AllocData ();

      copy->tid = cur->tid;

      copy->count = 1;

      copy->next = 0;

      memcpy (copy->data, cur->data, PACKET_TAG_MAX_SIZE);

      *prevNext = copy;

      prevNext = &copy->next;

    }

  *prevNext = 0;

  RemoveAll ();

  m_next = start;

  return true;

}

void 

PacketTagList::Add (const Tag &tag) const

{

  NS_LOG_FUNCTION (this << tag.GetInstanceTypeId ());

  // ensure this id was not yet added

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

    {

      NS_ASSERT (cur->tid != tag.GetInstanceTypeId ());

    }

  struct TagData *head = AllocData ();

  head->count = 1;

  head->next = 0;

  head->tid = tag.GetInstanceTypeId ();

  head->next = m_next;

  NS_ASSERT (tag.GetSerializedSize () < PACKET_TAG_MAX_SIZE);

  tag.Serialize (TagBuffer (head->data, head->data+tag.GetSerializedSize ()));

  const_cast<PacketTagList *> (this)->m_next = head;

}

bool

PacketTagList::Peek (Tag &tag) const

{

  NS_LOG_FUNCTION (this << tag.GetInstanceTypeId ());

  TypeId tid = tag.GetInstanceTypeId ();

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

    {

      if (cur->tid == tid) 

        {

          /* found tag */

          tag.Deserialize (TagBuffer (cur->data, cur->data+PACKET_TAG_MAX_SIZE));

          return true;

        }

    }

  /* no tag found */

  return false;

}

const struct PacketTagList::TagData *

PacketTagList::Head (void) const

{

  return m_next;

}

} // namespace ns3