| // -*- 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___FUNCTIONAL_BIND_BACK_H |
| #define _LIBCPP___FUNCTIONAL_BIND_BACK_H |
| |
| #include <__config> |
| #include <__functional/invoke.h> |
| #include <__functional/perfect_forward.h> |
| #include <__type_traits/decay.h> |
| #include <__utility/forward.h> |
| #include <__utility/integer_sequence.h> |
| #include <tuple> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER >= 20 |
| |
| template <size_t _NBound, class = make_index_sequence<_NBound>> |
| struct __bind_back_op; |
| |
| template <size_t _NBound, size_t... _Ip> |
| struct __bind_back_op<_NBound, index_sequence<_Ip...>> { |
| template <class _Fn, class _BoundArgs, class... _Args> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __f, _BoundArgs&& __bound_args, _Args&&... __args) const |
| noexcept(noexcept(std::invoke(std::forward<_Fn>(__f), |
| std::forward<_Args>(__args)..., |
| std::get<_Ip>(std::forward<_BoundArgs>(__bound_args))...))) |
| -> decltype(std::invoke(std::forward<_Fn>(__f), |
| std::forward<_Args>(__args)..., |
| std::get<_Ip>(std::forward<_BoundArgs>(__bound_args))...)) { |
| return std::invoke(std::forward<_Fn>(__f), |
| std::forward<_Args>(__args)..., |
| std::get<_Ip>(std::forward<_BoundArgs>(__bound_args))...); |
| } |
| }; |
| |
| template <class _Fn, class _BoundArgs> |
| struct __bind_back_t : __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs> { |
| using __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs>::__perfect_forward; |
| }; |
| |
| template <class _Fn, class... _Args> |
| requires is_constructible_v<decay_t<_Fn>, _Fn> && is_move_constructible_v<decay_t<_Fn>> && |
| (is_constructible_v<decay_t<_Args>, _Args> && ...) && (is_move_constructible_v<decay_t<_Args>> && ...) |
| _LIBCPP_HIDE_FROM_ABI constexpr auto __bind_back(_Fn&& __f, _Args&&... __args) noexcept( |
| noexcept(__bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>( |
| std::forward<_Fn>(__f), std::forward_as_tuple(std::forward<_Args>(__args)...)))) |
| -> decltype(__bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>( |
| std::forward<_Fn>(__f), std::forward_as_tuple(std::forward<_Args>(__args)...))) { |
| return __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>( |
| std::forward<_Fn>(__f), std::forward_as_tuple(std::forward<_Args>(__args)...)); |
| } |
| |
| # if _LIBCPP_STD_VER >= 23 |
| template <class _Fn, class... _Args> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto bind_back(_Fn&& __f, _Args&&... __args) { |
| static_assert(is_constructible_v<decay_t<_Fn>, _Fn>, "bind_back requires decay_t<F> to be constructible from F"); |
| static_assert(is_move_constructible_v<decay_t<_Fn>>, "bind_back requires decay_t<F> to be move constructible"); |
| static_assert((is_constructible_v<decay_t<_Args>, _Args> && ...), |
| "bind_back requires all decay_t<Args> to be constructible from respective Args"); |
| static_assert((is_move_constructible_v<decay_t<_Args>> && ...), |
| "bind_back requires all decay_t<Args> to be move constructible"); |
| return __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>( |
| std::forward<_Fn>(__f), std::forward_as_tuple(std::forward<_Args>(__args)...)); |
| } |
| # endif // _LIBCPP_STD_VER >= 23 |
| |
| #endif // _LIBCPP_STD_VER >= 20 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___FUNCTIONAL_BIND_BACK_H |