libcxx/include/__algorithm/ranges_sample.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___ALGORITHM_RANGES_SAMPLE_H
  10 #define _LIBCPP___ALGORITHM_RANGES_SAMPLE_H
  11
  12 #include <__algorithm/iterator_operations.h>
  13 #include <__algorithm/sample.h>
  14 #include <__algorithm/uniform_random_bit_generator_adaptor.h>
  15 #include <__config>
  16 #include <__iterator/concepts.h>
  17 #include <__iterator/incrementable_traits.h>
  18 #include <__iterator/iterator_traits.h>
  19 #include <__random/uniform_random_bit_generator.h>
  20 #include <__ranges/access.h>
  21 #include <__ranges/concepts.h>
  22 #include <__type_traits/remove_reference.h>
  23 #include <__utility/forward.h>
  24 #include <__utility/move.h>
  25
  26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  27 #  pragma GCC system_header
  28 #endif
  29
  30 _LIBCPP_PUSH_MACROS
  31 #include <__undef_macros>
  32
  33 #if _LIBCPP_STD_VER >= 20
  34
  35 _LIBCPP_BEGIN_NAMESPACE_STD
  36
  37 namespace ranges {
  38 struct __sample {
  39   template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Gen>
  40     requires(forward_iterator<_Iter> || random_access_iterator<_OutIter>) && indirectly_copyable<_Iter, _OutIter> &&
  41             uniform_random_bit_generator<remove_reference_t<_Gen>>
  42   _LIBCPP_HIDE_FROM_ABI _OutIter
  43   operator()(_Iter __first, _Sent __last, _OutIter __out_first, iter_difference_t<_Iter> __n, _Gen&& __gen) const {
  44     _ClassicGenAdaptor<_Gen> __adapted_gen(__gen);
  45     return std::__sample<_RangeAlgPolicy>(
  46         std::move(__first), std::move(__last), std::move(__out_first), __n, __adapted_gen);
  47   }
  48
  49   template <input_range _Range, weakly_incrementable _OutIter, class _Gen>
  50     requires(forward_range<_Range> || random_access_iterator<_OutIter>) &&
  51             indirectly_copyable<iterator_t<_Range>, _OutIter> && uniform_random_bit_generator<remove_reference_t<_Gen>>
  52   _LIBCPP_HIDE_FROM_ABI _OutIter
  53   operator()(_Range&& __range, _OutIter __out_first, range_difference_t<_Range> __n, _Gen&& __gen) const {
  54     return (*this)(
  55         ranges::begin(__range), ranges::end(__range), std::move(__out_first), __n, std::forward<_Gen>(__gen));
  56   }
  57 };
  58
  59 inline namespace __cpo {
  60 inline constexpr auto sample = __sample{};
  61 } // namespace __cpo
  62 } // namespace ranges
  63
  64 _LIBCPP_END_NAMESPACE_STD
  65
  66 #endif // _LIBCPP_STD_VER >= 20
  67
  68 _LIBCPP_POP_MACROS
  69
  70 #endif // _LIBCPP___ALGORITHM_RANGES_SAMPLE_H