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156ab87500
See: * https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc/77319 * https://discourse.llvm.org/t/rfc-project-hand-in-hand-llvm-libc-libc-code-sharing/77701 We're dropping support for C++03 for Zig due to the first change; it would be insane to ship 1018 duplicate header files just for this outdated use case. As a result of the second change, I had to bring in a subset of the headers from llvm-libc since libc++ now depends on these. Hopefully we can continue to get away with not copying the entirety of llvm-libc.
106 lines
4.6 KiB
C++
Vendored
106 lines
4.6 KiB
C++
Vendored
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
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#define _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
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#include <__config>
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#include <__cstddef/size_t.h>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/invoke.h>
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#include <__type_traits/is_constructible.h>
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#include <__utility/declval.h>
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#include <__utility/forward.h>
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#include <__utility/integer_sequence.h>
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#include <__utility/move.h>
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#include <tuple>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER >= 17
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template <class _Op, class _Indices, class... _BoundArgs>
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struct __perfect_forward_impl;
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template <class _Op, size_t... _Idx, class... _BoundArgs>
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struct __perfect_forward_impl<_Op, index_sequence<_Idx...>, _BoundArgs...> {
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private:
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tuple<_BoundArgs...> __bound_args_;
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public:
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template <class... _Args, class = enable_if_t< is_constructible_v<tuple<_BoundArgs...>, _Args&&...> >>
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_LIBCPP_HIDE_FROM_ABI explicit constexpr __perfect_forward_impl(_Args&&... __bound_args)
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: __bound_args_(std::forward<_Args>(__bound_args)...) {}
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_LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl const&) = default;
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_LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl&&) = default;
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_LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl const&) = default;
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_LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl&&) = default;
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template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs&..., _Args...>>>
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_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) & noexcept(
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noexcept(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)))
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-> decltype(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)) {
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return _Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...);
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}
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template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs&..., _Args...>>>
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auto operator()(_Args&&...) & = delete;
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template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const&..., _Args...>>>
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_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const& noexcept(
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noexcept(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)))
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-> decltype(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)) {
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return _Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...);
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}
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template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs const&..., _Args...>>>
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auto operator()(_Args&&...) const& = delete;
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template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs..., _Args...>>>
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_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) && noexcept(
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noexcept(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)))
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-> decltype(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)) {
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return _Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...);
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}
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template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs..., _Args...>>>
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auto operator()(_Args&&...) && = delete;
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template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const..., _Args...>>>
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_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&& noexcept(
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noexcept(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)))
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-> decltype(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)) {
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return _Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...);
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}
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template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs const..., _Args...>>>
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auto operator()(_Args&&...) const&& = delete;
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};
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// __perfect_forward implements a perfect-forwarding call wrapper as explained in [func.require].
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template <class _Op, class... _Args>
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using __perfect_forward _LIBCPP_NODEBUG = __perfect_forward_impl<_Op, index_sequence_for<_Args...>, _Args...>;
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#endif // _LIBCPP_STD_VER >= 17
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
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