Sprout/sprout/algorithm/fixed/shuffle_result.hpp
2012-05-14 11:33:36 +09:00

154 lines
5.4 KiB
C++

#ifndef SPROUT_ALGORITHM_FIXED_SHUFFLE_RESULT_HPP
#define SPROUT_ALGORITHM_FIXED_SHUFFLE_RESULT_HPP
#include <cstddef>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/index_tuple.hpp>
#include <sprout/array.hpp>
#include <sprout/pit.hpp>
#include <sprout/tuple/tuple.hpp>
#include <sprout/container/traits.hpp>
#include <sprout/container/functions.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/algorithm/fixed/result_of.hpp>
#include <sprout/algorithm/fixed/swap_element.hpp>
#include <sprout/numeric/fixed/iota.hpp>
#include <sprout/random/uniform_int_distribution.hpp>
namespace sprout {
namespace fixed {
namespace detail {
template<typename UniformRandomNumberGenerator, std::size_t N, typename Random>
inline SPROUT_CONSTEXPR sprout::tuples::tuple<
sprout::array<std::ptrdiff_t, N>,
typename std::decay<UniformRandomNumberGenerator>::type
> make_shuffle_result_indexes_1(
std::ptrdiff_t n,
Random const& rnd,
sprout::array<std::ptrdiff_t, N> const& arr,
std::ptrdiff_t i
)
{
typedef sprout::tuples::tuple<
sprout::array<std::ptrdiff_t, N>,
typename std::decay<UniformRandomNumberGenerator>::type
> result_type;
return i < n - 1
? sprout::fixed::detail::make_shuffle_result_indexes_1<UniformRandomNumberGenerator>(
n,
rnd(),
sprout::fixed::swap_element(arr, arr.begin() + i, arr.begin() + rnd.result()),
i + 1
)
: result_type(
sprout::fixed::swap_element(arr, arr.begin() + i, arr.begin() + rnd.result()),
rnd.engine()
)
;
}
template<std::size_t N, typename UniformRandomNumberGenerator>
inline SPROUT_CONSTEXPR sprout::tuples::tuple<
sprout::array<std::ptrdiff_t, N>,
typename std::decay<UniformRandomNumberGenerator>::type
> make_shuffle_result_indexes(
std::ptrdiff_t n,
UniformRandomNumberGenerator&& g
)
{
typedef sprout::tuples::tuple<
sprout::array<std::ptrdiff_t, N>,
typename std::decay<UniformRandomNumberGenerator>::type
> result_type;
return n > 0
? sprout::fixed::detail::make_shuffle_result_indexes_1<UniformRandomNumberGenerator>(
n,
sprout::random::uniform_int_distribution<std::ptrdiff_t>(0, n - 1)(sprout::forward<UniformRandomNumberGenerator>(g)),
sprout::fixed::iota(sprout::pit<sprout::array<std::ptrdiff_t, N> >(), 0),
0
)
: result_type(
sprout::array<std::ptrdiff_t, N>{{}},
sprout::forward<UniformRandomNumberGenerator>(g)
)
;
}
template<typename UniformRandomNumberGenerator, typename Container, typename Shuffled, sprout::index_t... Indexes>
inline SPROUT_CONSTEXPR sprout::tuples::tuple<
typename sprout::fixed::result_of::algorithm<Container>::type,
typename std::decay<UniformRandomNumberGenerator>::type
> shuffle_result_impl_1(
Container const& cont,
sprout::index_tuple<Indexes...>,
Shuffled const& shuffled,
typename sprout::container_traits<Container>::difference_type offset,
typename sprout::container_traits<Container>::size_type size
)
{
typedef sprout::tuples::tuple<
typename sprout::fixed::result_of::algorithm<Container>::type,
typename std::decay<UniformRandomNumberGenerator>::type
> result_type;
return result_type(
sprout::remake<Container>(
cont,
sprout::size(cont),
(Indexes >= offset && Indexes < offset + size
? *sprout::next(sprout::begin(cont), sprout::tuples::get<0>(shuffled)[Indexes - offset])
: *sprout::next(sprout::internal_begin(cont), Indexes)
)...
),
sprout::tuples::get<1>(shuffled)
);
}
template<typename Container, typename UniformRandomNumberGenerator, sprout::index_t... Indexes>
inline SPROUT_CONSTEXPR sprout::tuples::tuple<
typename sprout::fixed::result_of::algorithm<Container>::type,
typename std::decay<UniformRandomNumberGenerator>::type
> shuffle_result_impl(
Container const& cont,
sprout::index_tuple<Indexes...> indexes,
UniformRandomNumberGenerator&& g,
typename sprout::container_traits<Container>::difference_type offset,
typename sprout::container_traits<Container>::size_type size
)
{
return sprout::fixed::detail::shuffle_result_impl_1<UniformRandomNumberGenerator>(
cont,
indexes,
sprout::fixed::detail::make_shuffle_result_indexes<sprout::container_traits<Container>::static_size>(
size,
sprout::forward<UniformRandomNumberGenerator>(g)
),
offset,
size
);
}
} // namespace detail
//
// shuffle_result
//
template<typename Container, typename UniformRandomNumberGenerator>
inline SPROUT_CONSTEXPR sprout::tuples::tuple<
typename sprout::fixed::result_of::algorithm<Container>::type,
typename std::decay<UniformRandomNumberGenerator>::type
> shuffle_result(
Container const& cont,
UniformRandomNumberGenerator&& g
)
{
return sprout::fixed::detail::shuffle_result_impl(
cont,
sprout::index_range<0, sprout::container_traits<Container>::static_size>::make(),
sprout::forward<UniformRandomNumberGenerator>(g),
sprout::internal_begin_offset(cont),
sprout::size(cont)
);
}
} // namespace fixed
using sprout::fixed::shuffle_result;
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIXED_SHUFFLE_RESULT_HPP