90 lines · c
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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___PSTL_CPU_ALGOS_MERGE_H10#define _LIBCPP___PSTL_CPU_ALGOS_MERGE_H11 12#include <__algorithm/merge.h>13#include <__assert>14#include <__config>15#include <__iterator/concepts.h>16#include <__pstl/backend_fwd.h>17#include <__pstl/cpu_algos/cpu_traits.h>18#include <__type_traits/is_execution_policy.h>19#include <__utility/move.h>20#include <optional>21 22#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)23# pragma GCC system_header24#endif25 26_LIBCPP_PUSH_MACROS27#include <__undef_macros>28 29#if _LIBCPP_STD_VER >= 1730 31_LIBCPP_BEGIN_NAMESPACE_STD32namespace __pstl {33 34template <class _Backend, class _RawExecutionPolicy>35struct __cpu_parallel_merge {36 template <class _Policy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardOutIterator, class _Comp>37 _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator> operator()(38 _Policy&& __policy,39 _ForwardIterator1 __first1,40 _ForwardIterator1 __last1,41 _ForwardIterator2 __first2,42 _ForwardIterator2 __last2,43 _ForwardOutIterator __result,44 _Comp __comp) const noexcept {45 if constexpr (__is_parallel_execution_policy_v<_RawExecutionPolicy> &&46 __has_random_access_iterator_category_or_concept<_ForwardIterator1>::value &&47 __has_random_access_iterator_category_or_concept<_ForwardIterator2>::value &&48 __has_random_access_iterator_category_or_concept<_ForwardOutIterator>::value) {49 auto __res = __cpu_traits<_Backend>::__merge(50 __first1,51 __last1,52 __first2,53 __last2,54 __result,55 __comp,56 [&__policy](_ForwardIterator1 __g_first1,57 _ForwardIterator1 __g_last1,58 _ForwardIterator2 __g_first2,59 _ForwardIterator2 __g_last2,60 _ForwardOutIterator __g_result,61 _Comp __g_comp) {62 using _MergeUnseq = __pstl::__merge<_Backend, __remove_parallel_policy_t<_RawExecutionPolicy>>;63 [[maybe_unused]] auto __g_res = _MergeUnseq()(64 std::__remove_parallel_policy(__policy),65 std::move(__g_first1),66 std::move(__g_last1),67 std::move(__g_first2),68 std::move(__g_last2),69 std::move(__g_result),70 std::move(__g_comp));71 _LIBCPP_ASSERT_INTERNAL(__g_res, "unsed/sed should never try to allocate!");72 });73 if (!__res)74 return nullopt;75 return __result + (__last1 - __first1) + (__last2 - __first2);76 } else {77 return std::merge(__first1, __last1, __first2, __last2, __result, __comp);78 }79 }80};81 82} // namespace __pstl83_LIBCPP_END_NAMESPACE_STD84 85#endif // _LIBCPP_STD_VER >= 1786 87_LIBCPP_POP_MACROS88 89#endif // _LIBCPP___PSTL_CPU_ALGOS_MERGE_H90