xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/ranges_sample.h (revision b3edf4467982447620505a28fc82e38a414c07dc)
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 namespace __sample {
39 
40 struct __fn {
41   template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Gen>
42     requires(forward_iterator<_Iter> || random_access_iterator<_OutIter>) && indirectly_copyable<_Iter, _OutIter> &&
43             uniform_random_bit_generator<remove_reference_t<_Gen>>
44   _LIBCPP_HIDE_FROM_ABI _OutIter
45   operator()(_Iter __first, _Sent __last, _OutIter __out_first, iter_difference_t<_Iter> __n, _Gen&& __gen) const {
46     _ClassicGenAdaptor<_Gen> __adapted_gen(__gen);
47     return std::__sample<_RangeAlgPolicy>(
48         std::move(__first), std::move(__last), std::move(__out_first), __n, __adapted_gen);
49   }
50 
51   template <input_range _Range, weakly_incrementable _OutIter, class _Gen>
52     requires(forward_range<_Range> || random_access_iterator<_OutIter>) &&
53             indirectly_copyable<iterator_t<_Range>, _OutIter> && uniform_random_bit_generator<remove_reference_t<_Gen>>
54   _LIBCPP_HIDE_FROM_ABI _OutIter
55   operator()(_Range&& __range, _OutIter __out_first, range_difference_t<_Range> __n, _Gen&& __gen) const {
56     return (*this)(
57         ranges::begin(__range), ranges::end(__range), std::move(__out_first), __n, std::forward<_Gen>(__gen));
58   }
59 };
60 
61 } // namespace __sample
62 
63 inline namespace __cpo {
64 inline constexpr auto sample = __sample::__fn{};
65 } // namespace __cpo
66 } // namespace ranges
67 
68 _LIBCPP_END_NAMESPACE_STD
69 
70 #endif // _LIBCPP_STD_VER >= 20
71 
72 _LIBCPP_POP_MACROS
73 
74 #endif // _LIBCPP___ALGORITHM_RANGES_SAMPLE_H
75