libcxx/include/__algorithm/pstl_for_each.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___ALGORITHM_PSTL_FOR_EACH_H
  10 #define _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H
  11
  12 #include <__algorithm/for_each.h>
  13 #include <__algorithm/for_each_n.h>
  14 #include <__algorithm/pstl_backend.h>
  15 #include <__algorithm/pstl_frontend_dispatch.h>
  16 #include <__config>
  17 #include <__iterator/concepts.h>
  18 #include <__iterator/cpp17_iterator_concepts.h>
  19 #include <__type_traits/enable_if.h>
  20 #include <__type_traits/is_execution_policy.h>
  21 #include <__type_traits/remove_cvref.h>
  22 #include <__type_traits/void_t.h>
  23 #include <__utility/empty.h>
  24 #include <__utility/move.h>
  25 #include <optional>
  26
  27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28 #  pragma GCC system_header
  29 #endif
  30
  31 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  32
  33 _LIBCPP_BEGIN_NAMESPACE_STD
  34
  35 template <class _ExecutionPolicy,
  36           class _ForwardIterator,
  37           class _Function,
  38           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  39           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  40 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
  41 __for_each(_ExecutionPolicy&&, _ForwardIterator&& __first, _ForwardIterator&& __last, _Function&& __func) noexcept {
  42   using _Backend = typename __select_backend<_RawPolicy>::type;
  43   return std::__pstl_for_each<_RawPolicy>(_Backend{}, std::move(__first), std::move(__last), std::move(__func));
  44 }
  45
  46 template <class _ExecutionPolicy,
  47           class _ForwardIterator,
  48           class _Function,
  49           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  50           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  51 _LIBCPP_HIDE_FROM_ABI void
  52 for_each(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Function __func) {
  53   _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
  54   if (!std::__for_each(__policy, std::move(__first), std::move(__last), std::move(__func)))
  55     std::__throw_bad_alloc();
  56 }
  57
  58 template <class>
  59 void __pstl_for_each_n(); // declaration needed for the frontend dispatch below
  60
  61 template <class _ExecutionPolicy,
  62           class _ForwardIterator,
  63           class _Size,
  64           class _Function,
  65           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  66           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  67 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
  68 __for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _Size&& __size, _Function&& __func) noexcept {
  69   return std::__pstl_frontend_dispatch(
  70       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_for_each_n, _RawPolicy),
  71       [&](_ForwardIterator __g_first, _Size __g_size, _Function __g_func) -> optional<__empty> {
  72         if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
  73           std::for_each(__policy, std::move(__g_first), __g_first + __g_size, std::move(__g_func));
  74           return __empty{};
  75         } else {
  76           std::for_each_n(std::move(__g_first), __g_size, std::move(__g_func));
  77           return __empty{};
  78         }
  79       },
  80       std::move(__first),
  81       std::move(__size),
  82       std::move(__func));
  83 }
  84
  85 template <class _ExecutionPolicy,
  86           class _ForwardIterator,
  87           class _Size,
  88           class _Function,
  89           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  90           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  91 _LIBCPP_HIDE_FROM_ABI void
  92 for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) {
  93   _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
  94   auto __res = std::__for_each_n(__policy, std::move(__first), std::move(__size), std::move(__func));
  95   if (!__res)
  96     std::__throw_bad_alloc();
  97 }
  98
  99 _LIBCPP_END_NAMESPACE_STD
 100
 101 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 102
 103 #endif // _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H