Sprout/sprout/index_tuple/integer_n.hpp
2014-01-08 16:48:12 +09:00

93 lines
2.8 KiB
C++

/*=============================================================================
Copyright (c) 2011-2014 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#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
>
{};
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 detail
//
// integer_range
//
#if SPROUT_USE_TEMPLATE_ALIASES
template<typename T, T I, std::size_t N>
using integer_n = typename sprout::detail::integer_n<T, I, N>::type;
#else // #if SPROUT_USE_TEMPLATE_ALIASES
template<typename T, T I, std::size_t N>
struct integer_n
: public sprout::detail::integer_n<T, I, N>
{};
#endif // #if SPROUT_USE_TEMPLATE_ALIASES
} // namespace sprout
#endif // #ifndef SPROUT_INDEX_TUPLE_INTEGER_N_HPP