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 #if _LIBCPP_STD_VER >= 20
  31
  32 _LIBCPP_BEGIN_NAMESPACE_STD
  33
  34 namespace ranges {
  35 namespace __sample {
  36
  37 struct __fn {
  38   template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Gen>
  39     requires(forward_iterator<_Iter> || random_access_iterator<_OutIter>) && indirectly_copyable<_Iter, _OutIter> &&
  40             uniform_random_bit_generator<remove_reference_t<_Gen>>
  41   _LIBCPP_HIDE_FROM_ABI _OutIter
  42   operator()(_Iter __first, _Sent __last, _OutIter __out_first, iter_difference_t<_Iter> __n, _Gen&& __gen) const {
  43     _ClassicGenAdaptor<_Gen> __adapted_gen(__gen);
  44     return std::__sample<_RangeAlgPolicy>(
  45         std::move(__first), std::move(__last), std::move(__out_first), __n, __adapted_gen);
  46   }
  47
  48   template <input_range _Range, weakly_incrementable _OutIter, class _Gen>
  49     requires(forward_range<_Range> || random_access_iterator<_OutIter>) &&
  50             indirectly_copyable<iterator_t<_Range>, _OutIter> && uniform_random_bit_generator<remove_reference_t<_Gen>>
  51   _LIBCPP_HIDE_FROM_ABI _OutIter
  52   operator()(_Range&& __range, _OutIter __out_first, range_difference_t<_Range> __n, _Gen&& __gen) const {
  53     return (*this)(
  54         ranges::begin(__range), ranges::end(__range), std::move(__out_first), __n, std::forward<_Gen>(__gen));
  55   }
  56 };
  57
  58 } // namespace __sample
  59
  60 inline namespace __cpo {
  61 inline constexpr auto sample = __sample::__fn{};
  62 } // namespace __cpo
  63 } // namespace ranges
  64
  65 _LIBCPP_END_NAMESPACE_STD
  66
  67 #endif // _LIBCPP_STD_VER >= 20
  68
  69 #endif // _LIBCPP___ALGORITHM_RANGES_SAMPLE_H