iblt.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2024,  The University of Memphis
 *
 * This file is part of PSync.
 * See AUTHORS.md for complete list of PSync authors and contributors.
 *
 * PSync is free software: you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * PSync 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * PSync, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 
 * This file incorporates work covered by the following copyright and
 * permission notice:
 
 * The MIT License (MIT)
 
 * Copyright (c) 2014 Gavin Andresen
 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * furnished to do so, subject to the following conditions:
 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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*/
 
#ifndef PSYNC_DETAIL_IBLT_HPP
#define PSYNC_DETAIL_IBLT_HPP
 
#include "PSync/common.hpp"
 
#include <ndn-cxx/name.hpp>
 
#include <boost/operators.hpp>
 
#include <set>
#include <string>
 
namespace psync::detail {
 
class HashTableEntry : private boost::equality_comparable<HashTableEntry>
{
public:
  bool
  isPure() const;
 
  bool
  isEmpty() const;
 
private: // non-member operators
  // NOTE: the following "hidden friend" operators are available via
  //       argument-dependent lookup only and must be defined inline.
  // boost::equality_comparable provides != operator.
 
  friend bool
  operator==(const HashTableEntry& lhs, const HashTableEntry& rhs) noexcept
  {
    return lhs.count == rhs.count && lhs.keySum == rhs.keySum && lhs.keyCheck == rhs.keyCheck;
  }
 
public:
  int32_t count = 0;
  uint32_t keySum = 0;
  uint32_t keyCheck = 0;
};
 
inline constexpr size_t N_HASH = 3;
inline constexpr size_t N_HASHCHECK = 11;
 
class IBLT : private boost::equality_comparable<IBLT>
{
public:
  class Error : public std::runtime_error
  {
  public:
    using std::runtime_error::runtime_error;
  };
 
  explicit
  IBLT(size_t expectedNumEntries, CompressionScheme scheme);
 
  void
  initialize(const ndn::name::Component& ibltName);
 
  void
  insert(uint32_t key);
 
  void
  erase(uint32_t key);
 
  const std::vector<HashTableEntry>&
  getHashTable() const
  {
    return m_hashTable;
  }
 
  void
  appendToName(ndn::Name& name) const;
 
private: // non-member operators
  // NOTE: the following "hidden friend" operators are available via
  //       argument-dependent lookup only and must be defined inline.
  // boost::equality_comparable provides != operator.
 
  friend bool
  operator==(const IBLT& lhs, const IBLT& rhs)
  {
    return lhs.m_hashTable == rhs.m_hashTable;
  }
 
private:
  std::vector<HashTableEntry> m_hashTable;
  CompressionScheme m_compressionScheme;
};
 
std::ostream&
operator<<(std::ostream& os, const IBLT& iblt);
 
struct IBLTDiff
{
  bool canDecode = false;
 
  std::set<uint32_t> positive;
 
  std::set<uint32_t> negative;
};
 
IBLTDiff
operator-(const IBLT& lhs, const IBLT& rhs);
 
} // namespace psync::detail
 
#endif // PSYNC_DETAIL_IBLT_HPP