libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.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_BACKENDS_CPU_BACKENDS_THREAD_H
  10 #define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
  11
  12 #include <__assert>
  13 #include <__config>
  14 #include <__utility/empty.h>
  15 #include <__utility/move.h>
  16 #include <cstddef>
  17 #include <optional>
  18
  19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  20 #  pragma GCC system_header
  21 #endif
  22
  23 _LIBCPP_PUSH_MACROS
  24 #include <__undef_macros>
  25
  26 #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
  27
  28 // This backend implementation is for testing purposes only and not meant for production use. This will be replaced
  29 // by a proper implementation once the PSTL implementation is somewhat stable.
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 namespace __par_backend {
  34 inline namespace __thread_cpu_backend {
  35
  36 template <class _RandomAccessIterator, class _Fp>
  37 _LIBCPP_HIDE_FROM_ABI optional<__empty>
  38 __parallel_for(_RandomAccessIterator __first, _RandomAccessIterator __last, _Fp __f) {
  39   __f(__first, __last);
  40   return __empty{};
  41 }
  42
  43 template <class _Index, class _UnaryOp, class _Tp, class _BinaryOp, class _Reduce>
  44 _LIBCPP_HIDE_FROM_ABI optional<_Tp>
  45 __parallel_transform_reduce(_Index __first, _Index __last, _UnaryOp, _Tp __init, _BinaryOp, _Reduce __reduce) {
  46   return __reduce(std::move(__first), std::move(__last), std::move(__init));
  47 }
  48
  49 template <class _RandomAccessIterator, class _Compare, class _LeafSort>
  50 _LIBCPP_HIDE_FROM_ABI optional<__empty> __parallel_stable_sort(
  51     _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp, _LeafSort __leaf_sort) {
  52   __leaf_sort(__first, __last, __comp);
  53   return __empty{};
  54 }
  55
  56 _LIBCPP_HIDE_FROM_ABI inline void __cancel_execution() {}
  57
  58 template <class _RandomAccessIterator1,
  59           class _RandomAccessIterator2,
  60           class _RandomAccessIterator3,
  61           class _Compare,
  62           class _LeafMerge>
  63 _LIBCPP_HIDE_FROM_ABI optional<__empty> __parallel_merge(
  64     _RandomAccessIterator1 __first1,
  65     _RandomAccessIterator1 __last1,
  66     _RandomAccessIterator2 __first2,
  67     _RandomAccessIterator2 __last2,
  68     _RandomAccessIterator3 __outit,
  69     _Compare __comp,
  70     _LeafMerge __leaf_merge) {
  71   __leaf_merge(__first1, __last1, __first2, __last2, __outit, __comp);
  72   return __empty{};
  73 }
  74
  75 } // namespace __thread_cpu_backend
  76 } // namespace __par_backend
  77
  78 _LIBCPP_END_NAMESPACE_STD
  79
  80 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && && _LIBCPP_STD_VER >= 17
  81
  82 _LIBCPP_POP_MACROS
  83
  84 #endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H