MetaUtils.h

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#ifndef META_UTILS_H
#define META_UTILS_H
 
#include <tuple>
 
#define CHECK_TEST_RES(pred) MetaUtils::check(pred, __PRETTY_FUNCTION__)
 
namespace MetaUtils {
 
 
  template <class Func, std::size_t... Is>
  constexpr void staticForImpl(Func &&f,
                               std::index_sequence<Is...>) {
    // Use C++17 fold expressions to apply Func f
    // to all Is... in sequence
    //
    // Won't work on empty tuple (Binning is not intended to work with 0 dimensions).
    //
    // std::integral_constant used to encode value into type, otherwise it's not
    // possible to use Is inside functor as consant expression
    // (std::get<Is> etc. won't work)
 
    ((void)f(std::integral_constant<std::size_t, Is>()), ...);
  }
 
  template <size_t N, class Func>
  constexpr void staticFor(Func&& f) {
    staticForImpl(std::forward<Func>(f),
                  std::make_index_sequence<N>{});
  }
 
 
  template<class...> struct conjunction : std::true_type { };
  template<class B1> struct conjunction<B1> : B1 { };
  template<class B1, class... Bn>
  struct conjunction<B1, Bn...>
      : std::conditional_t<bool(B1::value), conjunction<Bn...>, B1> {};
 
  struct nonesuch {
    ~nonesuch() = delete;
    nonesuch(nonesuch const&) = delete;
    void operator=(nonesuch const&) = delete;
  };
 
  namespace operatorTraits {
    template<class T>
    using addition_assignment_t = decltype(std::declval<T&>() += std::declval<const T&>());
  }
 
  namespace detail {
    template <class Default, class AlwaysVoid,
              template<class...> class Op, class... Args>
    struct detector {
      using value_t = std::false_type;
      using type = Default;
    };
 
    template <class Default, template<class...> class Op, class... Args>
    struct detector<Default, std::void_t<Op<Args...>>, Op, Args...> {
      using value_t = std::true_type;
      using type = Op<Args...>;
    };
 
  } // namespace detail
 
  namespace {
    template <typename, template <typename...> class>
    struct is_instance_impl : public std::false_type {};
 
    template <template <typename...> class U, typename...Ts>
    struct is_instance_impl<U<Ts...>, U> : public std::true_type {};
  }
 
  template <typename T, template <typename ...> class U>
  using is_instance = is_instance_impl<std::decay_t<T>, U>;
 
  template <template<class...> class Op, class... Args>
  using is_detected = typename detail::detector<nonesuch, void, Op, Args...>::value_t;
 
  template <template<class...> class Op, class... Args>
  using detected_t = typename detail::detector<nonesuch, void, Op, Args...>::type;
 
  template <class Default, template<class...> class Op, class... Args>
  using detected_or = detail::detector<Default, void, Op, Args...>;
 
  template <class Expected, template<class...> class Op, class... Args>
  using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
 
  template< template<class...> class Op, class... Args >
  constexpr bool is_detected_v = is_detected<Op, Args...>::value;
 
  template <typename T, template <class U> class Concept>
  constexpr bool checkConcept() {
    return Concept<T>::checkResult::value;
  }
 
  inline int check(bool pred, const char* funcName) {
    if (pred == false)
      std::clog << funcName << " FAILED\n";
    return (int)(pred ? EXIT_SUCCESS : EXIT_FAILURE);
  }
 
 
  namespace {
 
    template <size_t, size_t>
    struct _tuple {
      template <typename T>
      static auto remove (const T& t) {
        return std::make_tuple(t);
      }
    };
 
    template <size_t N>
    struct _tuple<N, N> {
      template <typename T>
      static std::tuple<> remove (const T&) {
        return {};
      }
    };
 
    template<size_t N, typename T, size_t... Is>
    auto _removeTupleElement(const T& tup, std::index_sequence<Is...>) {
      return std::tuple_cat( _tuple<Is, N>::remove(std::get<Is>(tup))...);
    }
 
  }
 
  template<size_t I, typename... Ts>
  auto removeTupleElement(const std::tuple<Ts...>& tup) {
    return _removeTupleElement<I>(tup, std::make_index_sequence<sizeof...(Ts)>{});
  }
 
 
}
 
#endif