xref: /llvm-project/libcxx/include/__algorithm/ranges_count_if.h (revision eab7be5d42ad30c9992ff72c3be9298702001dc8)
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_COUNT_IF_H
10 #define _LIBCPP___ALGORITHM_RANGES_COUNT_IF_H
11 
12 #include <__algorithm/count_if.h>
13 #include <__algorithm/iterator_operations.h>
14 #include <__config>
15 #include <__functional/identity.h>
16 #include <__functional/ranges_operations.h>
17 #include <__iterator/concepts.h>
18 #include <__iterator/incrementable_traits.h>
19 #include <__iterator/iterator_traits.h>
20 #include <__iterator/projected.h>
21 #include <__ranges/access.h>
22 #include <__ranges/concepts.h>
23 #include <__utility/move.h>
24 
25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26 #  pragma GCC system_header
27 #endif
28 
29 _LIBCPP_PUSH_MACROS
30 #include <__undef_macros>
31 
32 #if _LIBCPP_STD_VER >= 20
33 
34 _LIBCPP_BEGIN_NAMESPACE_STD
35 
36 namespace ranges {
37 struct __count_if {
38   template <input_iterator _Iter,
39             sentinel_for<_Iter> _Sent,
40             class _Proj = identity,
41             indirect_unary_predicate<projected<_Iter, _Proj>> _Predicate>
42   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
43   operator()(_Iter __first, _Sent __last, _Predicate __pred, _Proj __proj = {}) const {
44     return std::__count_if<_RangeAlgPolicy>(std::move(__first), std::move(__last), __pred, __proj);
45   }
46 
47   template <input_range _Range,
48             class _Proj = identity,
49             indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Predicate>
50   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr range_difference_t<_Range>
51   operator()(_Range&& __r, _Predicate __pred, _Proj __proj = {}) const {
52     return std::__count_if<_RangeAlgPolicy>(ranges::begin(__r), ranges::end(__r), __pred, __proj);
53   }
54 };
55 
56 inline namespace __cpo {
57 inline constexpr auto count_if = __count_if{};
58 } // namespace __cpo
59 } // namespace ranges
60 
61 _LIBCPP_END_NAMESPACE_STD
62 
63 #endif // _LIBCPP_STD_VER >= 20
64 
65 _LIBCPP_POP_MACROS
66 
67 #endif // _LIBCPP___ALGORITHM_RANGES_COUNT_IF_H
68