cpp-game-engine/util/include/game/util/flyweight.hpp

//
//  flyweight.hpp
//  gameutils
//
//  Created by Sam Jaffe on 5/19/19.
//

#pragma once

#include <unordered_map>

#include "identity.hpp"

template <typename T> class flyweight {
private:
  static std::unordered_map<unsigned int, T> actual_;

public:
  const unsigned int id;

public:
  flyweight(unsigned int id, T actual) : id(id) {
    actual_.emplace(id, std::move(actual));
  }
  flyweight(identity<T> actual) : id(actual.id) {}
  T const & actual() const { return actual_.find(this->id)->second; }

  friend bool operator==(flyweight lhs, flyweight rhs) {
    return lhs.id == rhs.id;
  }
};

template <typename T> std::unordered_map<unsigned int, T> flyweight<T>::actual_;