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

/*

 * Copyright (c) 2011 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Manuel Requena <manuel.requena@cttc.es>

 */

#include "ns3/log.h"

#include "ns3/lte-rlc-header.h"

NS_LOG_COMPONENT_DEFINE ("LteRlcHeader");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (LteRlcHeader);

LteRlcHeader::LteRlcHeader ()

  : m_headerLength (0),

    m_framingInfo (0xff),

    m_sequenceNumber (0xfffa)

{

}

LteRlcHeader::~LteRlcHeader ()

{

    m_headerLength = 0;

    m_framingInfo = 0xff;

    m_sequenceNumber = 0xfffb;

}

void

LteRlcHeader::SetFramingInfo (uint8_t framingInfo)

{

  m_framingInfo = framingInfo & 0x03;

}

void

LteRlcHeader::SetSequenceNumber (SequenceNumber10 sequenceNumber)

{

  m_sequenceNumber = sequenceNumber;

}

uint8_t

LteRlcHeader::GetFramingInfo () const

{

  return m_framingInfo;

}

SequenceNumber10

LteRlcHeader::GetSequenceNumber () const

{

  return m_sequenceNumber;

}

void

LteRlcHeader::PushExtensionBit (uint8_t extensionBit)

{

  m_extensionBits.push_back (extensionBit);

  if (m_extensionBits.size() == 1)

    {

      m_headerLength = 2; // Only fixed part

    }

  else if (m_extensionBits.size() % 2)

    {

      m_headerLength += 1;

    }

  else

    {

      m_headerLength += 2;

    }

}

void

LteRlcHeader::PushLengthIndicator (uint16_t lengthIndicator)

{

  m_lengthIndicators.push_back (lengthIndicator);

}

uint8_t

LteRlcHeader::PopExtensionBit (void)

{

  uint8_t extensionBit = m_extensionBits.front ();

  m_extensionBits.pop_front ();

  return extensionBit;

}

uint16_t

LteRlcHeader::PopLengthIndicator (void)

{

  uint16_t lengthIndicator = m_lengthIndicators.front ();

  m_lengthIndicators.pop_front ();

  return lengthIndicator;

}

TypeId

LteRlcHeader::GetTypeId (void)

{

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

    .SetParent<Header> ()

    .AddConstructor<LteRlcHeader> ()

  ;

  return tid;

}

TypeId

LteRlcHeader::GetInstanceTypeId (void) const

{

  return GetTypeId ();

}

void LteRlcHeader::Print (std::ostream &os)  const

{

  std::list <uint8_t>::const_iterator it1 = m_extensionBits.begin ();

  std::list <uint16_t>::const_iterator it2 = m_lengthIndicators.begin ();

  os << "Len=" << m_headerLength;

  os << " FI=" << (uint16_t)m_framingInfo;

  os << " E=" << (uint16_t)(*it1);

  os << " SN=" << m_sequenceNumber;

  it1++;

  if (it1 != m_extensionBits.end ())

    {

      os << " E=";

    }

  while ( it1 != m_extensionBits.end () )

    {

      os << (uint16_t)(*it1);

      it1++;

    }

  if (it2 != m_lengthIndicators.end ())

    {

      os << " LI=";

    }

  while ( it2 != m_lengthIndicators.end () )

    {

      os << (uint16_t)(*it2) << " ";

      it2++;

    }

}

uint32_t LteRlcHeader::GetSerializedSize (void) const

{

  return m_headerLength;

}

void LteRlcHeader::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  std::list <uint8_t>::const_iterator it1 = m_extensionBits.begin ();

  std::list <uint16_t>::const_iterator it2 = m_lengthIndicators.begin ();

  i.WriteU8 ( ((m_framingInfo << 3) & 0x18) |

              (((*it1) << 2) & 0x04) |

              ((m_sequenceNumber.GetValue () >> 8) & 0x0003) );

  i.WriteU8 ( m_sequenceNumber.GetValue () & 0x00FF );

  it1++;

  while ( it1 != m_extensionBits.end () &&

          it2 != m_lengthIndicators.end () )

    {

      uint16_t oddLi, evenLi;

      uint8_t oddE, evenE;

      oddE = *it1;

      oddLi = *it2;

      it1++;

      it2++;

      if ( it1 != m_extensionBits.end () &&

           it2 != m_lengthIndicators.end () )

        {

          evenE = *it1;

          evenLi = *it2;

          i.WriteU8 ( ((oddE << 7) & 0x80) | ((oddLi >> 4) & 0x007F) );

          i.WriteU8 ( ((oddLi << 4) & 0x00F0) | ((evenE << 3) & 0x08) | ((evenLi >> 8) & 0x0007) );

          i.WriteU8 ( evenLi & 0x00FF );

          it1++;

          it2++;

        }

      else

        {

          i.WriteU8 ( ((oddE << 7) & 0x80) | ((oddLi >> 4) & 0x007F) );

          i.WriteU8 ( ((oddLi << 4) & 0x00F0) ); // Padding is implicit

        }

    }

}

uint32_t LteRlcHeader::Deserialize (Buffer::Iterator start)

{

  Buffer::Iterator i = start;

  uint8_t byte_1;

  uint8_t byte_2;

  uint8_t byte_3;

  uint8_t extensionBit;

  byte_1 = i.ReadU8 ();

  byte_2 = i.ReadU8 ();

  m_headerLength = 2;

  m_framingInfo = (byte_1 & 0x18) >> 3;

  m_sequenceNumber = ((byte_1 & 0x03) << 8) | byte_2;

  extensionBit = (byte_1 & 0x04) >> 2;

  m_extensionBits.push_back (extensionBit);

  if (extensionBit == DATA_FIELD_FOLLOWS)

    {

      return GetSerializedSize ();

    }

  uint16_t oddLi, evenLi;

  uint8_t oddE, evenE;

  bool moreLiFields = (extensionBit == E_LI_FIELDS_FOLLOWS);

  while (moreLiFields)

    {

      byte_1 = i.ReadU8 ();

      byte_2 = i.ReadU8 ();

      oddE = (byte_1 & 0x80) >> 7;

      oddLi = ((byte_1 & 0x7F) << 4) | ((byte_2 & 0xF0) >> 4);

      moreLiFields = (oddE == E_LI_FIELDS_FOLLOWS);

      m_extensionBits.push_back (oddE);

      m_lengthIndicators.push_back (oddLi);

      m_headerLength += 2;

      if (moreLiFields)

        {

          byte_3 = i.ReadU8 ();

          evenE = (byte_2 & 0x08) >> 3;

          evenLi = ((byte_2 & 0x07) << 8) | (byte_3 & 0xFF);

          moreLiFields = (evenE == E_LI_FIELDS_FOLLOWS);

          m_extensionBits.push_back (evenE);

          m_lengthIndicators.push_back (evenLi);

          m_headerLength += 1;

        }

    }

  return GetSerializedSize ();

}

}; // namespace ns3