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

/*

 * Copyright (c) 2007 University of Washington

 *

 * 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

 */

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/simulation-singleton.h"

#include "ipv4-address-generator.h"

NS_LOG_COMPONENT_DEFINE("Ipv4AddressGenerator");

namespace ns3 {

class Ipv4NetworkGeneratorImpl

{

public:

  Ipv4NetworkGeneratorImpl ();

  virtual ~Ipv4NetworkGeneratorImpl ();

  Ipv4Address Allocate (const Ipv4Mask mask);

  void Seed (const Ipv4Mask mask, const Ipv4Address network);

private:

  static const uint32_t N_BITS = 32;

  class State

  {

  public:

    uint32_t mask;

    uint32_t network;

  };

  State m_state[N_BITS];

};

Ipv4NetworkGeneratorImpl::Ipv4NetworkGeneratorImpl () 

{

  NS_LOG_FUNCTION;

  uint32_t mask = 0;

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      m_state[i].mask = mask;

      mask >>= 1;

      mask |= 0x80000000;

      m_state[i].network = 0;

      NS_LOG_LOGIC ("m_state[" << i << "]");

      NS_LOG_LOGIC ("mask = " << std::hex << m_state[i].mask);

      NS_LOG_LOGIC ("network = " << std::hex << m_state[i].network);

    }

}

Ipv4NetworkGeneratorImpl::~Ipv4NetworkGeneratorImpl ()

{

  NS_LOG_FUNCTION;

}

  void

Ipv4NetworkGeneratorImpl::Seed (

  const Ipv4Mask mask, 

  const Ipv4Address network)

{

  NS_LOG_FUNCTION;

  uint32_t maskBits = mask.GetHostOrder ();

  uint32_t networkBits = network.GetHostOrder ();

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      if (maskBits & 1)

        {

          uint32_t nMaskBits = N_BITS - i;

          NS_ASSERT(nMaskBits >= 0 && nMaskBits < N_BITS);

          m_state[nMaskBits].network = networkBits >> (N_BITS - i);

          return;

        }

      maskBits >>= 1;

    }

  NS_ASSERT_MSG(false, "Impossible");

  return;

}

  Ipv4Address

Ipv4NetworkGeneratorImpl::Allocate (const Ipv4Mask mask)

{

  NS_LOG_FUNCTION;

  uint32_t bits = mask.GetHostOrder ();

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      if (bits & 1)

        {

          uint32_t nBits = N_BITS - i;

          NS_ASSERT(nBits >= 0 && nBits < N_BITS);

          Ipv4Address addr (m_state[nBits].network << i);

          ++m_state[nBits].network;

          return addr;

        }

      bits >>= 1;

    }

  NS_ASSERT_MSG(false, "Impossible");

  return Ipv4Address (bits);

}

class Ipv4AddressGeneratorImpl

{

public:

  Ipv4AddressGeneratorImpl ();

  virtual ~Ipv4AddressGeneratorImpl ();

  Ipv4Address Allocate (const Ipv4Mask mask, const Ipv4Address network);

  void Seed (const Ipv4Mask mask, const Ipv4Address address);

private:

  static const uint32_t N_BITS = 32;

  class State

  {

  public:

    uint32_t mask;

    uint32_t address;

  };

  State m_state[N_BITS];

};

Ipv4AddressGeneratorImpl::Ipv4AddressGeneratorImpl () 

{

  NS_LOG_FUNCTION;

  uint32_t mask = 0;

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      m_state[i].mask = mask;

      mask >>= 1;

      mask |= 0x80000000;

      m_state[i].address = 0;

      NS_LOG_LOGIC ("m_state[" << i << "]");

      NS_LOG_LOGIC ("mask = " << std::hex << m_state[i].mask);

      NS_LOG_LOGIC ("address = " << std::hex << m_state[i].address);

    }

}

Ipv4AddressGeneratorImpl::~Ipv4AddressGeneratorImpl ()

{

  NS_LOG_FUNCTION;

}

  void

Ipv4AddressGeneratorImpl::Seed (

  const Ipv4Mask mask, 

  const Ipv4Address address)

{

  NS_LOG_FUNCTION;

  uint32_t maskBits = mask.GetHostOrder ();

  uint32_t addressBits = address.GetHostOrder ();

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      if (maskBits & 1)

        {

          uint32_t nMaskBits = N_BITS - i;

          NS_ASSERT(nMaskBits >= 0 && nMaskBits < N_BITS);

          m_state[nMaskBits].address = addressBits;

          return;

        }

      maskBits >>= 1;

    }

  NS_ASSERT_MSG(false, "Impossible");

  return;

}

  Ipv4Address

Ipv4AddressGeneratorImpl::Allocate (

  const Ipv4Mask mask,

  const Ipv4Address network)

{

  NS_LOG_FUNCTION;

  uint32_t bits = mask.GetHostOrder ();

  uint32_t net = network.GetHostOrder ();

  for (uint32_t i = 0; i < N_BITS; ++i)

    {

      if (bits & 1)

        {

          uint32_t nBits = N_BITS - i;

          NS_ASSERT(nBits >= 0 && nBits < N_BITS);

          Ipv4Address addr (net | m_state[nBits].address);

          ++m_state[nBits].address;

          NS_ASSERT_MSG((m_state[nBits].mask & m_state[nBits].address) == 0, 

            "Ipv4AddressGeneratorImpl::Allocate(): Overflow");

          return addr;

        }

      bits >>= 1;

    }

  NS_ASSERT_MSG(false, "Impossible");

  return Ipv4Address (bits);

}

  void

Ipv4AddressGenerator::SeedAddress (

  const Ipv4Mask mask, 

  const Ipv4Address address)

{

  NS_LOG_FUNCTION;

  SimulationSingleton<Ipv4AddressGeneratorImpl>::Get ()->Seed (mask, address);

}

  Ipv4Address

Ipv4AddressGenerator::AllocateAddress (

  const Ipv4Mask mask, 

  const Ipv4Address network)

{

  NS_LOG_FUNCTION;

  return SimulationSingleton<Ipv4AddressGeneratorImpl>::Get ()->

    Allocate (mask, network);

}

  void

Ipv4AddressGenerator::SeedNetwork (

  const Ipv4Mask mask,

  const Ipv4Address address)

{

  NS_LOG_FUNCTION;

  SimulationSingleton<Ipv4NetworkGeneratorImpl>::Get ()->Seed (mask, address);

}

  Ipv4Address

Ipv4AddressGenerator::AllocateNetwork (const Ipv4Mask mask)

{

  NS_LOG_FUNCTION;

  return SimulationSingleton<Ipv4NetworkGeneratorImpl>::Get ()->

    Allocate (mask);

}

}; // namespace ns3