xref: /llvm-project-15.0.7/libcxx/include/__algorithm/ranges_sample.h (revision 732cb123)

//===----------------------------------------------------------------------===//
//
// 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_SAMPLE_H
#define _LIBCPP___ALGORITHM_RANGES_SAMPLE_H

#include <__algorithm/iterator_operations.h>
#include <__algorithm/sample.h>
#include <__algorithm/uniform_random_bit_generator_adaptor.h>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/iterator_traits.h>
#include <__random/uniform_random_bit_generator.h>
#include <__ranges/access.h>
#include <__ranges/concepts.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_BEGIN_NAMESPACE_STD

namespace ranges {
namespace __sample {

struct __fn {

  template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Gen>
  requires (forward_iterator<_Iter> || random_access_iterator<_OutIter>) &&
           indirectly_copyable<_Iter, _OutIter> &&
           uniform_random_bit_generator<remove_reference_t<_Gen>>
  _LIBCPP_HIDE_FROM_ABI
  _OutIter operator()(_Iter __first, _Sent __last,
                      _OutIter __out_first, iter_difference_t<_Iter> __n, _Gen&& __gen) const {
    _ClassicGenAdaptor<_Gen> __adapted_gen(__gen);
    return std::__sample<_RangeAlgPolicy>(
        std::move(__first), std::move(__last), std::move(__out_first), __n, __adapted_gen);
  }

  template <input_range _Range, weakly_incrementable _OutIter, class _Gen>
  requires (forward_range<_Range> || random_access_iterator<_OutIter>) &&
           indirectly_copyable<iterator_t<_Range>, _OutIter> &&
           uniform_random_bit_generator<remove_reference_t<_Gen>>
  _LIBCPP_HIDE_FROM_ABI
  _OutIter operator()(_Range&& __range, _OutIter __out_first, range_difference_t<_Range> __n, _Gen&& __gen) const {
    return (*this)(ranges::begin(__range), ranges::end(__range),
                   std::move(__out_first), __n, std::forward<_Gen>(__gen));
  }

};

} // namespace __sample

inline namespace __cpo {
  inline constexpr auto sample = __sample::__fn{};
} // namespace __cpo
} // namespace ranges

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)

#endif // _LIBCPP___ALGORITHM_RANGES_SAMPLE_H