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

//
//  distribution.h
//  shared_random_generator
//
//  Created by Sam Jaffe on 3/25/23.
//  Copyright © 2023 Sam Jaffe. All rights reserved.
//

#pragma once

#include <iosfwd>
#include <type_traits>

#include <random/forwards.h>

namespace engine::random {
template <typename Rand> class Distribution {
public:
  using result_type = Rand;

  virtual ~Distribution() = default;
  virtual result_type operator()(Device & device) const = 0;
  // Allow us to operator on rvalue Devices as well
  result_type operator()(Device && device) const { return (*this)(device); }

private:
  virtual void describe(std::ostream & os) const {}
  friend std::ostream & operator<<(std::ostream & os,
                                   Distribution const & dist) {
    dist.describe(os);
    return os;
  }
};

template <typename Rand> class Uniform : public Distribution<Rand> {
public:
  using result_type = typename Distribution<Rand>::result_type;

  Uniform() : Uniform(0) {}
  Uniform(Rand min);
  Uniform(Rand min, Rand max);

  result_type operator()(Device & device) const override;

private:
  void describe(std::ostream &) const override;

private:
  Rand min_;
  Rand max_;
};

class Index : public Uniform<size_t> {
public:
  explicit Index(size_t size) : Uniform(0, size - 1) {}
};

class Boolean : public Uniform<int> {
public:
  Boolean() : Uniform(0, 1) {}
  void describe(std::ostream &os) const override;
};
}