Nikolas Klauser ebc05b93a1 [libc++][PSTL] Implement <execution> contents
Reviewed By: ldionne, #libc

Spies: libcxx-commits, arichardson

Differential Revision: https://reviews.llvm.org/D141888
2023-04-29 20:41:38 -07:00

116 lines
3.6 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_EXECUTION
#define _LIBCPP_EXECUTION
/*
namespace std::execution {
struct sequenced_policy;
struct parallel_policy;
struct parallel_unsequenced_policy;
struct unsequenced_policy; // since C++20
inline constexpr sequenced_policy seq = implementation-defined;
inline constexpr parallel_policy par = implementation-defined;
inline constexpr parallel_unsequenced_policy par_unseq = implementation-defined;
inline constexpr unsequenced_policy unseq = implementation-defined; // since C++20
}
namespace std {
template <class T>
struct is_execution_policy;
template <class T>
inline constexpr bool is_execution_policy_v;
}
*/
#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <__type_traits/integral_constant.h>
#include <version>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_STD
namespace execution {
struct __disable_user_instantiations_tag {
explicit __disable_user_instantiations_tag() = default;
};
struct sequenced_policy {
constexpr explicit sequenced_policy(__disable_user_instantiations_tag) {}
sequenced_policy(const sequenced_policy&) = delete;
sequenced_policy& operator=(const sequenced_policy&) = delete;
};
inline constexpr sequenced_policy seq{__disable_user_instantiations_tag{}};
struct parallel_policy {
constexpr explicit parallel_policy(__disable_user_instantiations_tag) {}
parallel_policy(const parallel_policy&) = delete;
parallel_policy& operator=(const parallel_policy&) = delete;
};
inline constexpr parallel_policy par{__disable_user_instantiations_tag{}};
struct parallel_unsequenced_policy {
constexpr explicit parallel_unsequenced_policy(__disable_user_instantiations_tag) {}
parallel_unsequenced_policy(const parallel_unsequenced_policy&) = delete;
parallel_unsequenced_policy& operator=(const parallel_unsequenced_policy&) = delete;
};
inline constexpr parallel_unsequenced_policy par_unseq{__disable_user_instantiations_tag{}};
# if _LIBCPP_STD_VER >= 20
struct unsequenced_policy {
constexpr explicit unsequenced_policy(__disable_user_instantiations_tag) {}
unsequenced_policy(const unsequenced_policy&) = delete;
unsequenced_policy& operator=(const unsequenced_policy&) = delete;
};
inline constexpr unsequenced_policy unseq{__disable_user_instantiations_tag{}};
# endif // _LIBCPP_STD_VER >= 20
} // namespace execution
template <class>
inline constexpr bool is_execution_policy_v = false;
template <>
inline constexpr bool is_execution_policy_v<execution::sequenced_policy> = true;
template <>
inline constexpr bool is_execution_policy_v<execution::parallel_policy> = true;
template <>
inline constexpr bool is_execution_policy_v<execution::parallel_unsequenced_policy> = true;
# if _LIBCPP_STD_VER >= 20
template <>
inline constexpr bool is_execution_policy_v<execution::unsequenced_policy> = true;
# endif
template <class _Tp>
struct is_execution_policy : bool_constant<is_execution_policy_v<_Tp>> {};
_LIBCPP_END_NAMESPACE_STD
#endif // defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
#endif // _LIBCPP_EXECUTION