libcxx/include/__algorithm/pstl_move.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_MOVE_H
  10 #define _LIBCPP___ALGORITHM_PSTL_MOVE_H
  11
  12 #include <__algorithm/copy_n.h>
  13 #include <__algorithm/pstl_frontend_dispatch.h>
  14 #include <__algorithm/pstl_transform.h>
  15 #include <__config>
  16 #include <__functional/identity.h>
  17 #include <__iterator/iterator_traits.h>
  18 #include <__type_traits/enable_if.h>
  19 #include <__type_traits/is_constant_evaluated.h>
  20 #include <__type_traits/is_execution_policy.h>
  21 #include <__type_traits/is_trivially_copyable.h>
  22 #include <__type_traits/remove_cvref.h>
  23 #include <optional>
  24
  25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  26 #  pragma GCC system_header
  27 #endif
  28
  29 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 // TODO: Use the std::copy/move shenanigans to forward to std::memmove
  34 //       Investigate whether we want to still forward to std::transform(policy)
  35 //       in that case for the execution::par part, or whether we actually want
  36 //       to run everything serially in that case.
  37
  38 template <class>
  39 void __pstl_move();
  40
  41 template <class _ExecutionPolicy,
  42           class _ForwardIterator,
  43           class _ForwardOutIterator,
  44           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  45           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  46 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
  47 __move(_ExecutionPolicy&& __policy,
  48        _ForwardIterator&& __first,
  49        _ForwardIterator&& __last,
  50        _ForwardOutIterator&& __result) noexcept {
  51   return std::__pstl_frontend_dispatch(
  52       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_move, _RawPolicy),
  53       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _ForwardOutIterator __g_result) {
  54         return std::__transform(__policy, __g_first, __g_last, __g_result, [](auto&& __v) { return std::move(__v); });
  55       },
  56       std::move(__first),
  57       std::move(__last),
  58       std::move(__result));
  59 }
  60
  61 template <class _ExecutionPolicy,
  62           class _ForwardIterator,
  63           class _ForwardOutIterator,
  64           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  65           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  66 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
  67 move(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
  68   auto __res = std::__move(__policy, std::move(__first), std::move(__last), std::move(__result));
  69   if (!__res)
  70     std::__throw_bad_alloc();
  71   return *__res;
  72 }
  73
  74 _LIBCPP_END_NAMESPACE_STD
  75
  76 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  77
  78 #endif // _LIBCPP___ALGORITHM_PSTL_MOVE_H