Sprout/sprout/index_tuple/index_range.hpp
2013-01-25 15:14:29 +09:00

81 lines
2.6 KiB
C++

#ifndef SPROUT_INDEX_TUPLE_INDEX_RANGE_HPP
#define SPROUT_INDEX_TUPLE_INDEX_RANGE_HPP
#include <cstddef>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/index_tuple/index_tuple.hpp>
#include <sprout/index_tuple/detail/make_indexes_helper.hpp>
namespace sprout {
//
// index_range
//
namespace detail {
template<typename IndexTuple, sprout::index_t Next>
struct index_range_next;
template<sprout::index_t... Indexes, sprout::index_t Next>
struct index_range_next<sprout::index_tuple<Indexes...>, Next> {
public:
typedef sprout::index_tuple<Indexes..., (Indexes + Next)...> type;
};
template<typename IndexTuple, sprout::index_t Next, sprout::index_t Tail>
struct index_range_next2;
template<sprout::index_t... Indexes, sprout::index_t Next, sprout::index_t Tail>
struct index_range_next2<sprout::index_tuple<Indexes...>, Next, Tail> {
public:
typedef sprout::index_tuple<Indexes..., (Indexes + Next)..., Tail> type;
};
template<sprout::index_t First, sprout::index_t Step, std::size_t N, typename Enable = void>
struct index_range_impl;
template<sprout::index_t First, sprout::index_t Step, std::size_t N>
struct index_range_impl<
First, Step, N,
typename std::enable_if<(N == 0)>::type
> {
public:
typedef sprout::index_tuple<> type;
};
template<sprout::index_t First, sprout::index_t Step, std::size_t N>
struct index_range_impl<
First, Step, N,
typename std::enable_if<(N == 1)>::type
> {
public:
typedef sprout::index_tuple<First> type;
};
template<sprout::index_t First, sprout::index_t Step, std::size_t N>
struct index_range_impl<
First, Step, N,
typename std::enable_if<(N > 1 && N % 2 == 0)>::type
>
: public sprout::detail::index_range_next<
typename sprout::detail::index_range_impl<First, Step, N / 2>::type,
First + N / 2 * Step
>
{};
template<sprout::index_t First, sprout::index_t Step, std::size_t N>
struct index_range_impl<
First, Step, N,
typename std::enable_if<(N > 1 && N % 2 == 1)>::type
>
: public sprout::detail::index_range_next2<
typename sprout::detail::index_range_impl<First, Step, N / 2>::type,
First + N / 2 * Step,
First + (N - 1) * Step
>
{};
} // namespace detail
template<sprout::index_t First, sprout::index_t Last, sprout::index_t Step = 1>
struct index_range
: public sprout::detail::make_indexes_helper<
sprout::detail::index_range_impl<
First, Step, ((Last - First) + (Step - 1)) / Step
>
>
{};
} // namespace sprout
#endif // #ifndef SPROUT_INDEX_TUPLE_INDEX_RANGE_HPP