libcxx/include/__algorithm/pstl_copy.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_COPY_H
  10 #define _LIBCPP___ALGORITHM_PSTL_COPY_H
  11
  12 #include <__algorithm/copy_n.h>
  13 #include <__algorithm/pstl_backend.h>
  14 #include <__algorithm/pstl_frontend_dispatch.h>
  15 #include <__algorithm/pstl_transform.h>
  16 #include <__config>
  17 #include <__functional/identity.h>
  18 #include <__iterator/concepts.h>
  19 #include <__type_traits/enable_if.h>
  20 #include <__type_traits/is_constant_evaluated.h>
  21 #include <__type_traits/is_execution_policy.h>
  22 #include <__type_traits/is_trivially_copyable.h>
  23 #include <__type_traits/remove_cvref.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 // TODO: Use the std::copy/move shenanigans to forward to std::memmove
  36
  37 template <class>
  38 void __pstl_copy();
  39
  40 template <class _ExecutionPolicy,
  41           class _ForwardIterator,
  42           class _ForwardOutIterator,
  43           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  44           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  45 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
  46 __copy(_ExecutionPolicy&& __policy,
  47        _ForwardIterator&& __first,
  48        _ForwardIterator&& __last,
  49        _ForwardOutIterator&& __result) noexcept {
  50   return std::__pstl_frontend_dispatch(
  51       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_copy, _RawPolicy),
  52       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _ForwardOutIterator __g_result) {
  53         return std::__transform(__policy, __g_first, __g_last, __g_result, __identity());
  54       },
  55       std::move(__first),
  56       std::move(__last),
  57       std::move(__result));
  58 }
  59
  60 template <class _ExecutionPolicy,
  61           class _ForwardIterator,
  62           class _ForwardOutIterator,
  63           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  64           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  65 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
  66 copy(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
  67   auto __res = std::__copy(__policy, std::move(__first), std::move(__last), std::move(__result));
  68   if (!__res)
  69     std::__throw_bad_alloc();
  70   return *std::move(__res);
  71 }
  72
  73 template <class>
  74 void __pstl_copy_n();
  75
  76 template <class _ExecutionPolicy,
  77           class _ForwardIterator,
  78           class _ForwardOutIterator,
  79           class _Size,
  80           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
  81           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
  82 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator> __copy_n(
  83     _ExecutionPolicy&& __policy, _ForwardIterator&& __first, _Size&& __n, _ForwardOutIterator&& __result) noexcept {
  84   return std::__pstl_frontend_dispatch(
  85       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_copy_n, _RawPolicy),
  86       [&__policy](
  87           _ForwardIterator __g_first, _Size __g_n, _ForwardOutIterator __g_result) -> optional<_ForwardIterator> {
  88         if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value)
  89           return std::__copy(__policy, std::move(__g_first), std::move(__g_first + __g_n), std::move(__g_result));
  90         else
  91           return std::copy_n(__g_first, __g_n, __g_result);
  92       },
  93       std::move(__first),
  94       std::move(__n),
  95       std::move(__result));
  96 }
  97
  98 template <class _ExecutionPolicy,
  99           class _ForwardIterator,
 100           class _ForwardOutIterator,
 101           class _Size,
 102           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
 103           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 104 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
 105 copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
 106   auto __res = std::__copy_n(__policy, std::move(__first), std::move(__n), std::move(__result));
 107   if (!__res)
 108     std::__throw_bad_alloc();
 109   return *std::move(__res);
 110 }
 111
 112 _LIBCPP_END_NAMESPACE_STD
 113
 114 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 115
 116 #endif // _LIBCPP___ALGORITHM_PSTL_COPY_H