v3/action/shuffle.hpp

0001 /// \file
0002 // Range v3 library
0003 //
0004 //  Copyright Filip Matzner 2015
0005 //
0006 //  Use, modification and distribution is subject to the
0007 //  Boost Software License, Version 1.0. (See accompanying
0008 //  file LICENSE_1_0.txt or copy at
0009 //  http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // Project home: https://github.com/ericniebler/range-v3
0012 //
0013
0014 #ifndef RANGES_V3_ACTION_SHUFFLE_HPP
0015 #define RANGES_V3_ACTION_SHUFFLE_HPP
0016
0017 #include <range/v3/range_fwd.hpp>
0018
0019 #include <range/v3/action/action.hpp>
0020 #include <range/v3/algorithm/shuffle.hpp>
0021 #include <range/v3/functional/bind.hpp>
0022 #include <range/v3/functional/bind_back.hpp>
0023 #include <range/v3/functional/invoke.hpp>
0024 #include <range/v3/iterator/concepts.hpp>
0025 #include <range/v3/iterator/traits.hpp>
0026 #include <range/v3/utility/static_const.hpp>
0027
0028 #include <range/v3/detail/prologue.hpp>
0029
0030 namespace ranges
0031 {
0032     /// \addtogroup group-actions
0033     /// @{
0034     namespace actions
0035     {
0036         struct shuffle_fn
0037         {
0038             template(typename Gen)(
0039                 requires uniform_random_bit_generator<Gen>)
0040             constexpr auto operator()(Gen & gen) const
0041             {
0042                 return make_action_closure(
0043                     bind_back(shuffle_fn{}, detail::reference_wrapper_<Gen>(gen)));
0044             }
0045
0046             template(typename Gen)(
0047                 requires uniform_random_bit_generator<Gen>)
0048             constexpr auto operator()(Gen && gen) const
0049             {
0050                 return make_action_closure(
0051                     bind_back(shuffle_fn{}, static_cast<Gen &&>(gen)));
0052             }
0053
0054             template(typename Rng, typename Gen)(
0055                 requires random_access_range<Rng> AND permutable<iterator_t<Rng>> AND
0056                     uniform_random_bit_generator<std::remove_reference_t<Gen>> AND
0057                     convertible_to<invoke_result_t<Gen &>, range_difference_t<Rng>>)
0058             Rng operator()(Rng && rng, Gen && gen) const
0059             {
0060                 ranges::shuffle(rng, static_cast<Gen &&>(gen));
0061                 return static_cast<Rng &&>(rng);
0062             }
0063
0064             /// \cond
0065             template<typename Rng, typename T>
0066             invoke_result_t<shuffle_fn, Rng, T &> //
0067             operator()(Rng && rng, detail::reference_wrapper_<T> r) const
0068             {
0069                 return (*this)(static_cast<Rng &&>(rng), r.get());
0070             }
0071             /// \endcond
0072         };
0073
0074         /// \relates actions::shuffle_fn
0075         /// \sa `action_closure`
0076         RANGES_INLINE_VARIABLE(shuffle_fn, shuffle)
0077     } // namespace actions
0078     /// @}
0079 } // namespace ranges
0080
0081 #include <range/v3/detail/epilogue.hpp>
0082
0083 #endif