| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___ALGORITHM_RANGES_SHUFFLE_H |
| #define _LIBCPP___ALGORITHM_RANGES_SHUFFLE_H |
| |
| #include <__algorithm/iterator_operations.h> |
| #include <__algorithm/shuffle.h> |
| #include <__config> |
| #include <__functional/invoke.h> |
| #include <__functional/ranges_operations.h> |
| #include <__iterator/concepts.h> |
| #include <__iterator/iterator_traits.h> |
| #include <__iterator/next.h> |
| #include <__iterator/permutable.h> |
| #include <__random/uniform_random_bit_generator.h> |
| #include <__ranges/access.h> |
| #include <__ranges/concepts.h> |
| #include <__ranges/dangling.h> |
| #include <__utility/forward.h> |
| #include <__utility/move.h> |
| #include <type_traits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| namespace ranges { |
| namespace __shuffle { |
| |
| struct __fn { |
| // `std::shuffle` is more constrained than `std::ranges::shuffle`. `std::ranges::shuffle` only requires the given |
| // generator to satisfy the `std::uniform_random_bit_generator` concept. `std::shuffle` requires the given |
| // generator to meet the uniform random bit generator requirements; these requirements include satisfying |
| // `std::uniform_random_bit_generator` and add a requirement for the generator to provide a nested `result_type` |
| // typedef (see `[rand.req.urng]`). |
| // |
| // To reuse the implementation from `std::shuffle`, make the given generator meet the classic requirements by wrapping |
| // it into an adaptor type that forwards all of its interface and adds the required typedef. |
| template <class _Gen> |
| class _ClassicGenAdaptor { |
| private: |
| // The generator is not required to be copyable or movable, so it has to be stored as a reference. |
| _Gen& __gen; |
| |
| public: |
| using result_type = invoke_result_t<_Gen&>; |
| |
| _LIBCPP_HIDE_FROM_ABI |
| static constexpr auto min() { return __uncvref_t<_Gen>::min(); } |
| _LIBCPP_HIDE_FROM_ABI |
| static constexpr auto max() { return __uncvref_t<_Gen>::max(); } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr explicit _ClassicGenAdaptor(_Gen& __g) : __gen(__g) {} |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr auto operator()() const { return __gen(); } |
| }; |
| |
| template <random_access_iterator _Iter, sentinel_for<_Iter> _Sent, class _Gen> |
| requires permutable<_Iter> && uniform_random_bit_generator<remove_reference_t<_Gen>> |
| _LIBCPP_HIDE_FROM_ABI |
| _Iter operator()(_Iter __first, _Sent __last, _Gen&& __gen) const { |
| _ClassicGenAdaptor<_Gen> __adapted_gen(__gen); |
| return std::__shuffle<_RangeAlgPolicy>(std::move(__first), std::move(__last), __adapted_gen); |
| } |
| |
| template<random_access_range _Range, class _Gen> |
| requires permutable<iterator_t<_Range>> && uniform_random_bit_generator<remove_reference_t<_Gen>> |
| _LIBCPP_HIDE_FROM_ABI |
| borrowed_iterator_t<_Range> operator()(_Range&& __range, _Gen&& __gen) const { |
| return (*this)(ranges::begin(__range), ranges::end(__range), std::forward<_Gen>(__gen)); |
| } |
| |
| }; |
| |
| } // namespace __shuffle |
| |
| inline namespace __cpo { |
| inline constexpr auto shuffle = __shuffle::__fn{}; |
| } // namespace __cpo |
| } // namespace ranges |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) |
| |
| #endif // _LIBCPP___ALGORITHM_RANGES_SHUFFLE_H |