xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/ranges_count.h (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
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_H
10 #define _LIBCPP___ALGORITHM_RANGES_COUNT_H
11 
12 #include <__algorithm/ranges_count_if.h>
13 #include <__config>
14 #include <__functional/identity.h>
15 #include <__functional/ranges_operations.h>
16 #include <__iterator/concepts.h>
17 #include <__iterator/incrementable_traits.h>
18 #include <__iterator/iterator_traits.h>
19 #include <__iterator/projected.h>
20 #include <__ranges/access.h>
21 #include <__ranges/concepts.h>
22 #include <__utility/move.h>
23 
24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25 #  pragma GCC system_header
26 #endif
27 
28 #if _LIBCPP_STD_VER >= 20
29 
30 _LIBCPP_BEGIN_NAMESPACE_STD
31 
32 namespace ranges {
33 namespace __count {
34 struct __fn {
35   template <input_iterator _Iter, sentinel_for<_Iter> _Sent, class _Type, class _Proj = identity>
36     requires indirect_binary_predicate<ranges::equal_to, projected<_Iter, _Proj>, const _Type*>
37   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
38   operator()(_Iter __first, _Sent __last, const _Type& __value, _Proj __proj = {}) const {
39     auto __pred = [&](auto&& __e) { return __e == __value; };
40     return ranges::__count_if_impl(std::move(__first), std::move(__last), __pred, __proj);
41   }
42 
43   template <input_range _Range, class _Type, class _Proj = identity>
44     requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Range>, _Proj>, const _Type*>
45   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr range_difference_t<_Range>
46   operator()(_Range&& __r, const _Type& __value, _Proj __proj = {}) const {
47     auto __pred = [&](auto&& __e) { return __e == __value; };
48     return ranges::__count_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
49   }
50 };
51 } // namespace __count
52 
53 inline namespace __cpo {
54 inline constexpr auto count = __count::__fn{};
55 } // namespace __cpo
56 } // namespace ranges
57 
58 _LIBCPP_END_NAMESPACE_STD
59 
60 #endif // _LIBCPP_STD_VER >= 20
61 
62 #endif // _LIBCPP___ALGORITHM_RANGES_COUNT_H
63