cpp-shared-random-generator/include/random/random.h

#pragma once

#include <cassert>
#include <memory>

#include <random/forwards.h>

namespace engine::random {
class Random {
private:
  std::shared_ptr<Device> impl_;
  std::shared_ptr<Tape> tape_{nullptr};

public:
  Random();
  template <typename P> Random(P const & p) : impl_(std::make_shared<P>(p)) {}
  template <typename P> Random(std::shared_ptr<P> const & p) : impl_(p) {}
  
  unsigned int exclusive(unsigned int max) const;
  double exclusive(double min, double max) const;
  double inclusive(double min, double max) const;
  
  std::shared_ptr<Device> device() const { return impl_; }
  
  /**
   * Create a scope in which all calls to the generator functions will record
   * their results into a tape. Expects that there is no tape currently set.
   * @param tape The tape to write to
   * @return A scope object that stops recording once it is descructed
   */
  auto record(std::shared_ptr<Tape> tape) {
    assert(tape && !tape_);
    tape_ = tape;
    auto cleanup = [this](void *) { tape_.reset(); };
    return std::unique_ptr<void, decltype(cleanup)>(this, cleanup);
  }
};
}