libcxx/include/__numeric/pstl_reduce.h

   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___NUMERIC_PSTL_REDUCE_H
  10 #define _LIBCPP___NUMERIC_PSTL_REDUCE_H
  11
  12 #include <__algorithm/pstl_frontend_dispatch.h>
  13 #include <__config>
  14 #include <__functional/identity.h>
  15 #include <__iterator/iterator_traits.h>
  16 #include <__numeric/pstl_transform_reduce.h>
  17 #include <__type_traits/is_execution_policy.h>
  18
  19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  20 #  pragma GCC system_header
  21 #endif
  22
  23 _LIBCPP_PUSH_MACROS
  24 #include <__undef_macros>
  25
  26 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 template <class>
  31 void __pstl_reduce();
  32
  33 template <class _ExecutionPolicy,
  34           class _ForwardIterator,
  35           class _Tp,
  36           class _BinaryOperation                              = plus<>,
  37           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  38           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  39 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_Tp>
  40 __reduce(_ExecutionPolicy&& __policy,
  41          _ForwardIterator&& __first,
  42          _ForwardIterator&& __last,
  43          _Tp&& __init,
  44          _BinaryOperation&& __op = {}) noexcept {
  45   return std::__pstl_frontend_dispatch(
  46       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_reduce, _RawPolicy),
  47       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _Tp __g_init, _BinaryOperation __g_op) {
  48         return std::__transform_reduce(
  49             __policy, std::move(__g_first), std::move(__g_last), std::move(__g_init), std::move(__g_op), __identity{});
  50       },
  51       std::move(__first),
  52       std::move(__last),
  53       std::move(__init),
  54       std::move(__op));
  55 }
  56
  57 template <class _ExecutionPolicy,
  58           class _ForwardIterator,
  59           class _Tp,
  60           class _BinaryOperation                              = plus<>,
  61           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  62           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  63 _LIBCPP_HIDE_FROM_ABI _Tp
  64 reduce(_ExecutionPolicy&& __policy,
  65        _ForwardIterator __first,
  66        _ForwardIterator __last,
  67        _Tp __init,
  68        _BinaryOperation __op = {}) {
  69   auto __res = std::__reduce(__policy, std::move(__first), std::move(__last), std::move(__init), std::move(__op));
  70   if (!__res)
  71     std::__throw_bad_alloc();
  72   return *std::move(__res);
  73 }
  74
  75 template <class _ExecutionPolicy,
  76           class _ForwardIterator,
  77           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  78           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  79 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_value_type<_ForwardIterator>>
  80 __reduce(_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last) noexcept {
  81   return std::__pstl_frontend_dispatch(
  82       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_reduce, _RawPolicy),
  83       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last) {
  84         return std::__reduce(
  85             __policy, std::move(__g_first), std::move(__g_last), __iter_value_type<_ForwardIterator>());
  86       },
  87       std::move(__first),
  88       std::move(__last));
  89 }
  90
  91 template <class _ExecutionPolicy,
  92           class _ForwardIterator,
  93           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  94           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  95 _LIBCPP_HIDE_FROM_ABI __iter_value_type<_ForwardIterator>
  96 reduce(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last) {
  97   auto __res = std::__reduce(__policy, std::move(__first), std::move(__last));
  98   if (!__res)
  99     std::__throw_bad_alloc();
 100   return *std::move(__res);
 101 }
 102
 103 _LIBCPP_END_NAMESPACE_STD
 104
 105 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 106
 107 _LIBCPP_POP_MACROS
 108
 109 #endif // _LIBCPP___NUMERIC_PSTL_REDUCE_H