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Sprout/sprout/algorithm/fixed/random_swap.hpp
2015-01-10 19:13:57 +09:00

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3.7 KiB
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/*=============================================================================
Copyright (c) 2011-2015 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_ALGORITHM_FIXED_RANDOM_SWAP_HPP
#define SPROUT_ALGORITHM_FIXED_RANDOM_SWAP_HPP
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/array/array.hpp>
#include <sprout/container/traits.hpp>
#include <sprout/container/functions.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/utility/pair/pair.hpp>
#include <sprout/algorithm/fixed/results.hpp>
#include <sprout/algorithm/fixed/swap_element.hpp>
#include <sprout/random/results.hpp>
#include <sprout/workaround/detail/uniform_int_distribution.hpp>
namespace sprout {
namespace fixed {
namespace detail {
template<typename Random>
inline SPROUT_CONSTEXPR sprout::array<std::ptrdiff_t, 2>
make_random_swap_indexes_2(Random const& rnd, std::ptrdiff_t i0) {
return sprout::array<std::ptrdiff_t, 2>{{i0, sprout::random::result(rnd)}};
}
template<typename Random>
inline SPROUT_CONSTEXPR sprout::array<std::ptrdiff_t, 2>
make_random_swap_indexes_1(Random const& rnd) {
return sprout::fixed::detail::make_random_swap_indexes_2(
sprout::random::next(rnd)(),
sprout::random::result(rnd)
);
}
template<typename UniformRandomNumberGenerator>
inline SPROUT_CONSTEXPR sprout::array<std::ptrdiff_t, 2>
make_random_swap_indexes(std::ptrdiff_t n, UniformRandomNumberGenerator&& g) {
return n > 1
? sprout::fixed::detail::make_random_swap_indexes_1(
SPROUT_WORKAROUND_DETAIL_UNIFORM_INT_DISTRIBUTION<std::ptrdiff_t>(0, n - 1)(
SPROUT_FORWARD(UniformRandomNumberGenerator, g)
)
)
: sprout::array<std::ptrdiff_t, 2>{{}}
;
}
template<typename Container, typename RandomSwapped>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
random_swap_impl_1(Container const& cont, RandomSwapped const& random_swapped) {
return random_swapped[0] == random_swapped[1]
? sprout::deep_copy(cont)
: sprout::fixed::swap_element(
cont,
sprout::next(sprout::begin(cont), random_swapped[0]),
sprout::next(sprout::begin(cont), random_swapped[1])
)
;
}
template<typename Container, typename UniformRandomNumberGenerator>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
random_swap_impl(
Container const& cont, UniformRandomNumberGenerator&& g,
typename sprout::container_traits<Container>::size_type size
)
{
return sprout::fixed::detail::random_swap_impl_1(
cont,
sprout::fixed::detail::make_random_swap_indexes(
size,
SPROUT_FORWARD(UniformRandomNumberGenerator, g)
)
);
}
} // namespace detail
//
// random_swap
//
template<typename Container, typename UniformRandomNumberGenerator>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
random_swap(Container const& cont, UniformRandomNumberGenerator&& g) {
return sprout::fixed::detail::random_swap_impl(
cont, SPROUT_FORWARD(UniformRandomNumberGenerator, g),
sprout::size(cont)
);
}
} // namespace fixed
using sprout::fixed::random_swap;
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIXED_RANDOM_SWAP_HPP