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 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  24
  25 _LIBCPP_BEGIN_NAMESPACE_STD
  26
  27 template <class>
  28 void __pstl_reduce();
  29
  30 template <class _ExecutionPolicy,
  31           class _ForwardIterator,
  32           class _Tp,
  33           class _BinaryOperation                              = plus<>,
  34           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  35           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  36 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_Tp>
  37 __reduce(_ExecutionPolicy&& __policy,
  38          _ForwardIterator&& __first,
  39          _ForwardIterator&& __last,
  40          _Tp&& __init,
  41          _BinaryOperation&& __op = {}) noexcept {
  42   return std::__pstl_frontend_dispatch(
  43       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_reduce, _RawPolicy),
  44       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _Tp __g_init, _BinaryOperation __g_op) {
  45         return std::__transform_reduce(
  46             __policy, std::move(__g_first), std::move(__g_last), std::move(__g_init), std::move(__g_op), __identity{});
  47       },
  48       std::move(__first),
  49       std::move(__last),
  50       std::move(__init),
  51       std::move(__op));
  52 }
  53
  54 template <class _ExecutionPolicy,
  55           class _ForwardIterator,
  56           class _Tp,
  57           class _BinaryOperation                              = plus<>,
  58           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  59           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  60 _LIBCPP_HIDE_FROM_ABI _Tp
  61 reduce(_ExecutionPolicy&& __policy,
  62        _ForwardIterator __first,
  63        _ForwardIterator __last,
  64        _Tp __init,
  65        _BinaryOperation __op = {}) {
  66   auto __res = std::__reduce(__policy, std::move(__first), std::move(__last), std::move(__init), std::move(__op));
  67   if (!__res)
  68     std::__throw_bad_alloc();
  69   return *std::move(__res);
  70 }
  71
  72 template <class _ExecutionPolicy,
  73           class _ForwardIterator,
  74           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  75           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  76 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_value_type<_ForwardIterator>>
  77 __reduce(_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last) noexcept {
  78   return std::__pstl_frontend_dispatch(
  79       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_reduce, _RawPolicy),
  80       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last) {
  81         return std::__reduce(
  82             __policy, std::move(__g_first), std::move(__g_last), __iter_value_type<_ForwardIterator>());
  83       },
  84       std::move(__first),
  85       std::move(__last));
  86 }
  87
  88 template <class _ExecutionPolicy,
  89           class _ForwardIterator,
  90           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  91           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  92 _LIBCPP_HIDE_FROM_ABI __iter_value_type<_ForwardIterator>
  93 reduce(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last) {
  94   auto __res = std::__reduce(__policy, std::move(__first), std::move(__last));
  95   if (!__res)
  96     std::__throw_bad_alloc();
  97   return *std::move(__res);
  98 }
  99
 100 _LIBCPP_END_NAMESPACE_STD
 101
 102 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 103
 104 #endif // _LIBCPP___NUMERIC_PSTL_REDUCE_H