nexthop.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2023,  The 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/>.
 */
 
#ifndef NLSR_ROUTE_NEXTHOP_HPP
#define NLSR_ROUTE_NEXTHOP_HPP
 
#include "test-access-control.hpp"
 
#include <ndn-cxx/encoding/block.hpp>
#include <ndn-cxx/encoding/encoding-buffer.hpp>
#include <ndn-cxx/encoding/tlv.hpp>
#include <ndn-cxx/net/face-uri.hpp>
 
#include <boost/operators.hpp>
 
#include <cmath>
#include <ostream>
 
namespace nlsr {
 
class NextHop : private boost::totally_ordered<NextHop>
{
public:
  using Error = ndn::tlv::Error;
 
  NextHop() = default;
 
  NextHop(const ndn::FaceUri& cfu, double rc)
    : m_connectingFaceUri(cfu)
    , m_routeCost(rc)
  {
  }
 
  explicit
  NextHop(const ndn::Block& block)
  {
    wireDecode(block);
  }
 
  const ndn::FaceUri&
  getConnectingFaceUri() const
  {
    return m_connectingFaceUri;
  }
 
  void
  setConnectingFaceUri(const ndn::FaceUri& 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(const double rc)
  {
    m_routeCost = rc;
  }
 
  void
  setHyperbolic(bool b)
  {
    m_isHyperbolic = b;
  }
 
  bool
  isHyperbolic() const
  {
    return m_isHyperbolic;
  }
 
  template<ndn::encoding::Tag TAG>
  size_t
  wireEncode(ndn::EncodingImpl<TAG>& block) const;
 
  const ndn::Block&
  wireEncode() const;
 
  void
  wireDecode(const ndn::Block& wire);
 
private: // non-member operators
  // NOTE: the following "hidden friend" operators are available via
  //       argument-dependent lookup only and must be defined inline.
  // boost::totally_ordered provides !=, <=, >=, and > operators.
 
  friend bool
  operator==(const NextHop& lhs, const NextHop& rhs)
  {
    return lhs.getRouteCostAsAdjustedInteger() == rhs.getRouteCostAsAdjustedInteger() &&
           lhs.getConnectingFaceUri() == rhs.getConnectingFaceUri();
  }
 
  friend bool
  operator<(const NextHop& lhs, const NextHop& rhs)
  {
    return std::forward_as_tuple(lhs.getRouteCostAsAdjustedInteger(), lhs.getConnectingFaceUri()) <
           std::forward_as_tuple(rhs.getRouteCostAsAdjustedInteger(), rhs.getConnectingFaceUri());
  }
 
private:
  ndn::FaceUri m_connectingFaceUri;
  double m_routeCost = 0.0;
  bool m_isHyperbolic = false;
 
  mutable ndn::Block m_wire;
 
PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  static constexpr uint64_t HYPERBOLIC_COST_ADJUSTMENT_FACTOR = 1000;
};
 
NDN_CXX_DECLARE_WIRE_ENCODE_INSTANTIATIONS(NextHop);
 
std::ostream&
operator<<(std::ostream& os, const NextHop& hop);
 
} // namespace nlsr
 
#endif // NLSR_ROUTE_NEXTHOP_HPP