#ifndef EINA_CXX_EINA_INTEGER_SEQUENCE_HH
#define EINA_CXX_EINA_INTEGER_SEQUENCE_HH

namespace efl { namespace eina {

template <typename T, T... Ints>
struct integer_sequence
{
  typedef T value_type;
  static constexpr std::size_t size() { return sizeof...(Ints); }
  typedef integer_sequence<T, Ints...> type;
};

template<class S1, class S2> struct concat;

template<typename T, T... I1, T... I2>
struct concat<integer_sequence<T, I1...>, integer_sequence<T, I2...> >
  : integer_sequence<T, I1..., (sizeof...(I1)+I2)...> {};

template<class S1, class S2>
using Concat = typename concat<S1, S2>::type;

template<typename T, T N> struct gen_seq;
template<typename T, T N> using make_integer_sequence = typename gen_seq<T, N>::type;

template<typename T, T N>
struct gen_seq : Concat<make_integer_sequence<T, N/2>
                        , make_integer_sequence<T, N - N/2>>{};

template<> struct gen_seq<std::size_t, 0> : integer_sequence<std::size_t>{};
template<> struct gen_seq<std::size_t, 1> : integer_sequence<std::size_t, 0>{};

template <std::size_t... I>
using index_sequence = integer_sequence<std::size_t, I...>;

template <std::size_t I>
using make_index_sequence = make_integer_sequence<std::size_t, I>;

} }

#endif