2 //===----------------------------------------------------------------------===//
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8 //===----------------------------------------------------------------------===//
10 #ifndef _LIBCPP___FUNCTIONAL_BIND_BACK_H
11 #define _LIBCPP___FUNCTIONAL_BIND_BACK_H
14 #include <__functional/invoke.h>
15 #include <__functional/perfect_forward.h>
16 #include <__type_traits/decay.h>
17 #include <__utility/forward.h>
18 #include <__utility/integer_sequence.h>
21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22 # pragma GCC system_header
25 _LIBCPP_BEGIN_NAMESPACE_STD
27 #if _LIBCPP_STD_VER >= 20
29 template <size_t _NBound, class = make_index_sequence<_NBound>>
30 struct __bind_back_op;
32 template <size_t _NBound, size_t ..._Ip>
33 struct __bind_back_op<_NBound, index_sequence<_Ip...>> {
34 template <class _Fn, class _BoundArgs, class... _Args>
35 _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __f, _BoundArgs&& __bound_args, _Args&&... __args) const
36 noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...)))
37 -> decltype( _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...))
38 { return _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...); }
41 template <class _Fn, class _BoundArgs>
42 struct __bind_back_t : __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs> {
43 using __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs>::__perfect_forward;
46 template <class _Fn, class ..._Args, class = enable_if_t<
48 is_constructible<decay_t<_Fn>, _Fn>,
49 is_move_constructible<decay_t<_Fn>>,
50 is_constructible<decay_t<_Args>, _Args>...,
51 is_move_constructible<decay_t<_Args>>...
55 constexpr auto __bind_back(_Fn&& __f, _Args&&... __args)
56 noexcept(noexcept(__bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...))))
57 -> decltype( __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)))
58 { return __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)); }
60 #endif // _LIBCPP_STD_VER >= 20
62 _LIBCPP_END_NAMESPACE_STD
64 #endif // _LIBCPP___FUNCTIONAL_BIND_BACK_H