xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/ranges_sample.h (revision 6246ae0b85d8159978c01ae916a9ad6cde9378b5)
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 <__utility/forward.h>
23 #include <__utility/move.h>
24 #include <type_traits>
25 
26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27 #  pragma GCC system_header
28 #endif
29 
30 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 namespace ranges {
35 namespace __sample {
36 
37 struct __fn {
38 
39   template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Gen>
40   requires (forward_iterator<_Iter> || random_access_iterator<_OutIter>) &&
41            indirectly_copyable<_Iter, _OutIter> &&
42            uniform_random_bit_generator<remove_reference_t<_Gen>>
43   _LIBCPP_HIDE_FROM_ABI
44   _OutIter operator()(_Iter __first, _Sent __last,
45                       _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> &&
54            uniform_random_bit_generator<remove_reference_t<_Gen>>
55   _LIBCPP_HIDE_FROM_ABI
56   _OutIter operator()(_Range&& __range, _OutIter __out_first, range_difference_t<_Range> __n, _Gen&& __gen) const {
57     return (*this)(ranges::begin(__range), ranges::end(__range),
58                    std::move(__out_first), __n, std::forward<_Gen>(__gen));
59   }
60 
61 };
62 
63 } // namespace __sample
64 
65 inline namespace __cpo {
66   inline constexpr auto sample = __sample::__fn{};
67 } // namespace __cpo
68 } // namespace ranges
69 
70 _LIBCPP_END_NAMESPACE_STD
71 
72 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
73 
74 #endif // _LIBCPP___ALGORITHM_RANGES_SAMPLE_H
75