mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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118 lines
4.4 KiB
C++
118 lines
4.4 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2017 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_ALGORITHM_FIXED_SHUFFLE_HPP
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#define SPROUT_ALGORITHM_FIXED_SHUFFLE_HPP
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#include <sprout/config.hpp>
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#include <sprout/workaround/std/cstddef.hpp>
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#include <sprout/index_tuple/metafunction.hpp>
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#include <sprout/array/array.hpp>
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#include <sprout/pit/pit.hpp>
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#include <sprout/container/traits.hpp>
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#include <sprout/container/functions.hpp>
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#include <sprout/container/indexes.hpp>
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#include <sprout/iterator/operation.hpp>
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#include <sprout/utility/forward.hpp>
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#include <sprout/algorithm/fixed/results.hpp>
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#include <sprout/algorithm/fixed/swap_element.hpp>
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#include <sprout/numeric/fixed/iota.hpp>
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#include <sprout/random/results.hpp>
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#include <sprout/workaround/detail/uniform_int_distribution.hpp>
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namespace sprout {
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namespace fixed {
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namespace detail {
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template<std::size_t N, typename Random>
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inline SPROUT_CONSTEXPR sprout::array<std::ptrdiff_t, N>
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make_shuffle_indexes_1(std::ptrdiff_t n, Random const& rnd, sprout::array<std::ptrdiff_t, N> const& arr, std::ptrdiff_t i) {
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return i < n - 1
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? sprout::fixed::detail::make_shuffle_indexes_1(
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n,
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sprout::random::next(rnd)(),
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sprout::fixed::swap_element(arr, arr.begin() + i, arr.begin() + sprout::random::result(rnd)),
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i + 1
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)
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: sprout::fixed::swap_element(arr, arr.begin() + i, arr.begin() + sprout::random::result(rnd))
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;
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}
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template<std::size_t N, typename UniformRandomNumberGenerator>
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inline SPROUT_CONSTEXPR sprout::array<std::ptrdiff_t, N>
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make_shuffle_indexes(std::ptrdiff_t n, UniformRandomNumberGenerator&& g) {
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return n > 1
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? sprout::fixed::detail::make_shuffle_indexes_1(
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n,
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SPROUT_WORKAROUND_DETAIL_UNIFORM_INT_DISTRIBUTION<std::ptrdiff_t>(0, n - 1)(
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SPROUT_FORWARD(UniformRandomNumberGenerator, g)
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),
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sprout::fixed::iota(sprout::pit<sprout::array<std::ptrdiff_t, N> >(), 0),
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0
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)
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: sprout::array<std::ptrdiff_t, N>{{}}
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;
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}
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template<typename Container, typename Shuffled, sprout::index_t... Indexes>
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inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
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shuffle_impl_1(
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Container const& cont,
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sprout::index_tuple<Indexes...>,
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Shuffled const& shuffled,
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typename sprout::container_traits<Container>::difference_type offset,
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typename sprout::container_traits<Container>::size_type size
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)
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{
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return sprout::remake<Container>(
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cont,
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sprout::size(cont),
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(Indexes >= offset && Indexes < offset + size
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? *sprout::next(sprout::begin(cont), shuffled[Indexes - offset])
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: *sprout::next(sprout::internal_begin(cont), Indexes)
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)...
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);
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}
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template<typename Container, typename UniformRandomNumberGenerator, sprout::index_t... Indexes>
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inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
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shuffle_impl(
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Container const& cont,
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sprout::index_tuple<Indexes...> indexes,
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UniformRandomNumberGenerator&& g,
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typename sprout::container_traits<Container>::difference_type offset,
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typename sprout::container_traits<Container>::size_type size
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)
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{
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return sprout::fixed::detail::shuffle_impl_1(
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cont,
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indexes,
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sprout::fixed::detail::make_shuffle_indexes<sprout::container_traits<Container>::static_size>(
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size,
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SPROUT_FORWARD(UniformRandomNumberGenerator, g)
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),
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offset,
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size
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);
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}
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} // namespace detail
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//
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// shuffle
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//
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template<typename Container, typename UniformRandomNumberGenerator>
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inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
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shuffle(Container const& cont, UniformRandomNumberGenerator&& g) {
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return sprout::fixed::detail::shuffle_impl(
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cont,
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sprout::container_indexes<Container>::make(),
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SPROUT_FORWARD(UniformRandomNumberGenerator, g),
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sprout::internal_begin_offset(cont),
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sprout::size(cont)
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);
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}
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} // namespace fixed
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using sprout::fixed::shuffle;
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} // namespace sprout
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#endif // #ifndef SPROUT_ALGORITHM_FIXED_SHUFFLE_HPP
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