TransferElementID.h

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// SPDX-FileCopyrightText: Deutsches Elektronen-Synchrotron DESY, MSK, ChimeraTK Project <chimeratk-support@desy.de>
// SPDX-License-Identifier: LGPL-3.0-or-later
#pragma once
 
#include <cstddef>
#include <functional>
#include <iosfwd>
 
namespace ChimeraTK {
 
  /********************************************************************************************************************/
 
  class TransferElementID {
   public:
    TransferElementID() = default;
 
    TransferElementID(const TransferElementID& other) = default;
 
    bool operator==(const TransferElementID& other) const { return (_id != 0) && (_id == other._id); }
    bool operator!=(const TransferElementID& other) const { return !(operator==(other)); }
 
    [[nodiscard]] bool isValid() const { return _id != 0; }
 
    TransferElementID& operator=(const TransferElementID& other) = default;
 
   protected:
    void makeUnique();
 
    size_t _id{0};
 
    // Hash function for putting TransferElement::ID e.g. into an std::unordered_map
    friend struct std::hash<TransferElementID>;
 
    // Comparison for putting TransferElement::ID e.g. into an std::map
    friend struct std::less<TransferElementID>;
 
    friend std::ostream& operator<<(std::ostream& os, const TransferElementID& me);
    friend class TransferElement;
  };
 
  /********************************************************************************************************************/
 
  std::ostream& operator<<(std::ostream& os, const TransferElementID& me);
 
  /********************************************************************************************************************/
 
} // namespace ChimeraTK
 
namespace std {
 
  /********************************************************************************************************************/
 
  template<>
  struct hash<ChimeraTK::TransferElementID> {
    std::size_t operator()(const ChimeraTK::TransferElementID& f) const { return std::hash<size_t>{}(f._id); }
  };
 
  /********************************************************************************************************************/
 
  template<>
  struct less<ChimeraTK::TransferElementID> {
    bool operator()(const ChimeraTK::TransferElementID& a, const ChimeraTK::TransferElementID& b) const {
      return a._id < b._id;
    }
  };
} // namespace std