Sprout/sprout/index_tuple/integer_n.hpp
bolero-MURAKAMI bb36ef6e8b support for N3658 (Compile-time integer sequences): index_tuple
rename: integer_seq -> integer_sequence, make_integer_sequence -> make_integer_sequence
add unsigned-index sequence: index_sequence(alias), make_index_sequence, index_sequence_for
add: integer_pack, index_pack
2013-05-10 19:52:39 +09:00

73 lines
2.1 KiB
C++

#ifndef SPROUT_INDEX_TUPLE_INTEGER_N_HPP
#define SPROUT_INDEX_TUPLE_INTEGER_N_HPP
#include <cstddef>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/index_tuple/integer_sequence.hpp>
#include <sprout/index_tuple/enable_make_indexes.hpp>
namespace sprout {
//
// integer_n
//
namespace detail {
template<typename T, typename Seq>
struct integer_n_next_even;
template<typename T, T... Is>
struct integer_n_next_even<T, sprout::integer_sequence<T, Is...> >
: public sprout::integer_sequence<T, Is..., Is...>
{};
template<typename T, typename Seq, T Tail>
struct integer_n_next_even_odd;
template<typename T, T... Is, T Tail>
struct integer_n_next_even_odd<T, sprout::integer_sequence<T, Is...>, Tail>
: public sprout::integer_sequence<T, Is..., Is..., Tail>
{};
template<typename T, T I, std::size_t N, typename Enable = void>
struct integer_n_impl;
template<typename T, T I, std::size_t N>
struct integer_n_impl<
T, I, N,
typename std::enable_if<(N == 0)>::type
>
: public sprout::integer_sequence<T>
{};
template<typename T, T I, std::size_t N>
struct integer_n_impl<
T, I, N,
typename std::enable_if<(N == 1)>::type
>
: public sprout::integer_sequence<T, I>
{};
template<typename T, T I, std::size_t N>
struct integer_n_impl<
T, I, N,
typename std::enable_if<(N > 1 && N % 2 == 0)>::type
>
: public sprout::detail::integer_n_next_even<
T, typename sprout::detail::integer_n_impl<T, I, N / 2>::type
>
{};
template<typename T, T I, std::size_t N>
struct integer_n_impl<
T, I, N,
typename std::enable_if<(N > 1 && N % 2 == 1)>::type
>
: public sprout::detail::integer_n_next_even_odd<
T, typename sprout::detail::integer_n_impl<T, I, N / 2>::type,
I
>
{};
} // namespace detail
template<typename T, T I, std::size_t N>
struct integer_n
: public sprout::enable_make_indexes<
sprout::detail::integer_n_impl<T, I, N>
>
{};
} // namespace sprout
#endif // #ifndef SPROUT_INDEX_TUPLE_INTEGER_N_HPP