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_PSTL_COUNT_H
10 #define _LIBCPP___ALGORITHM_PSTL_COUNT_H
11 
12 #include <__algorithm/count.h>
13 #include <__algorithm/for_each.h>
14 #include <__algorithm/pstl_backend.h>
15 #include <__algorithm/pstl_for_each.h>
16 #include <__algorithm/pstl_frontend_dispatch.h>
17 #include <__atomic/atomic.h>
18 #include <__config>
19 #include <__functional/operations.h>
20 #include <__iterator/iterator_traits.h>
21 #include <__numeric/pstl_transform_reduce.h>
22 #include <__type_traits/enable_if.h>
23 #include <__type_traits/is_execution_policy.h>
24 #include <__type_traits/remove_cvref.h>
25 #include <__utility/move.h>
26 #include <optional>
27 
28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
29 #  pragma GCC system_header
30 #endif
31 
32 _LIBCPP_PUSH_MACROS
33 #include <__undef_macros>
34 
35 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
36 
37 _LIBCPP_BEGIN_NAMESPACE_STD
38 
39 template <class>
40 void __pstl_count_if(); // declaration needed for the frontend dispatch below
41 
42 template <class _ExecutionPolicy,
43           class _ForwardIterator,
44           class _Predicate,
45           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
46           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
47 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>> __count_if(
48     _ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last, _Predicate&& __pred) noexcept {
49   using __diff_t = __iter_diff_t<_ForwardIterator>;
50   return std::__pstl_frontend_dispatch(
51       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_count_if, _RawPolicy),
52       [&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Predicate __g_pred) -> optional<__diff_t> {
53         return std::__transform_reduce(
54             __policy,
55             std::move(__g_first),
56             std::move(__g_last),
57             __diff_t(),
58             std::plus{},
59             [&](__iter_reference<_ForwardIterator> __element) -> bool { return __g_pred(__element); });
60       },
61       std::move(__first),
62       std::move(__last),
63       std::move(__pred));
64 }
65 
66 template <class _ExecutionPolicy,
67           class _ForwardIterator,
68           class _Predicate,
69           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
70           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
71 _LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
72 count_if(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
73   auto __res = std::__count_if(__policy, std::move(__first), std::move(__last), std::move(__pred));
74   if (!__res)
75     std::__throw_bad_alloc();
76   return *std::move(__res);
77 }
78 
79 template <class>
80 void __pstl_count(); // declaration needed for the frontend dispatch below
81 
82 template <class _ExecutionPolicy,
83           class _ForwardIterator,
84           class _Tp,
85           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
86           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
87 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>>
88 __count(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
89   return std::__pstl_frontend_dispatch(
90       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_count, _RawPolicy),
91       [&](_ForwardIterator __g_first, _ForwardIterator __g_last, const _Tp& __g_value)
92           -> optional<__iter_diff_t<_ForwardIterator>> {
93         return std::count_if(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __v) {
94           return __v == __g_value;
95         });
96       },
97       std::move(__first),
98       std::move(__last),
99       __value);
100 }
101 
102 template <class _ExecutionPolicy,
103           class _ForwardIterator,
104           class _Tp,
105           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
106           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
107 _LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
108 count(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
109   auto __res = std::__count(__policy, std::move(__first), std::move(__last), __value);
110   if (!__res)
111     std::__throw_bad_alloc();
112   return *__res;
113 }
114 
115 _LIBCPP_END_NAMESPACE_STD
116 
117 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
118 
119 _LIBCPP_POP_MACROS
120 
121 #endif // _LIBCPP___ALGORITHM_PSTL_COUNT_H
122