src/route/nexthop.hpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014  University of Memphis,
 *                     Regents of the University of California
 *
 * This file is part of NLSR (Named-data Link State Routing).
 * See AUTHORS.md for complete list of NLSR authors and contributors.
 *
 * NLSR is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NLSR 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
 * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * \author A K M Mahmudul Hoque <ahoque1@memphis.edu>
 *
 **/
#ifndef NLSR_NEXTHOP_HPP
#define NLSR_NEXTHOP_HPP

#include "test-access-control.hpp"

#include <iostream>
#include <cmath>
#include <boost/cstdint.hpp>

namespace nlsr {
class NextHop
{
public:
  NextHop()
    : m_connectingFaceUri()
    , m_routeCost(0)
    , m_isHyperbolic(false)
  {
  }

  NextHop(const std::string& cfu, double rc)
    : m_isHyperbolic(false)
  {
    m_connectingFaceUri = cfu;
    m_routeCost = rc;
  }

  const std::string&
  getConnectingFaceUri() const
  {
    return m_connectingFaceUri;
  }

  void
  setConnectingFaceUri(const std::string& cfu)
  {
    m_connectingFaceUri = cfu;
  }

  uint64_t
  getRouteCostAsAdjustedInteger() const
  {
    if (m_isHyperbolic) {
      // Round the cost to better preserve decimal cost differences
      // e.g. Without rounding: 12.3456 > 12.3454 -> 12345 = 12345
      //      With rounding:    12.3456 > 12.3454 -> 12346 > 12345
      return static_cast<uint64_t>(round(m_routeCost*HYPERBOLIC_COST_ADJUSTMENT_FACTOR));
    }
    else {
      return static_cast<uint64_t>(m_routeCost);
    }
  }

  double
  getRouteCost() const
  {
    return m_routeCost;
  }

  void
  setRouteCost(double rc)
  {
    m_routeCost = rc;
  }

  void
  setHyperbolic(bool b)
  {
    m_isHyperbolic = b;
  }

  bool
  isHyperbolic() const
  {
    return m_isHyperbolic;
  }

private:
  std::string m_connectingFaceUri;
  double m_routeCost;
  bool m_isHyperbolic;

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  /** \brief Used to adjust floating point route costs to integers
  *   Since NFD uses integer route costs in the FIB, hyperbolic paths with similar route costs
  *   will be rounded to integers and installed with identical nexthop costs.
  *
  *   e.g. costs 12.34 and 12.35 will be equal in NFD's FIB
  *
  *   This multiplier is used to differentiate similar route costs in the FIB.
  *
  *   e.g  costs 12.34 and 12.35 will be installed into NFD's FIB as 12340 and 12350
  */
  static const uint64_t HYPERBOLIC_COST_ADJUSTMENT_FACTOR = 1000;
};

std::ostream&
operator<<(std::ostream& os, const NextHop& hop);

}//namespace nlsr

#endif //NLSR_NEXTHOP_HPP