1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 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 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___FUNCTIONAL_BIND_BACK_H 11 #define _LIBCPP___FUNCTIONAL_BIND_BACK_H 12 13 #include <__config> 14 #include <__functional/invoke.h> 15 #include <__functional/perfect_forward.h> 16 #include <__utility/forward.h> 17 #include <__utility/integer_sequence.h> 18 #include <tuple> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 #if _LIBCPP_STD_VER >= 20 27 28 template <size_t _NBound, class = make_index_sequence<_NBound>> 29 struct __bind_back_op; 30 31 template <size_t _NBound, size_t ..._Ip> 32 struct __bind_back_op<_NBound, index_sequence<_Ip...>> { 33 template <class _Fn, class _BoundArgs, class... _Args> 34 _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __f, _BoundArgs&& __bound_args, _Args&&... __args) const 35 noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...))) 36 -> decltype( _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...)) 37 { return _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...); } 38 }; 39 40 template <class _Fn, class _BoundArgs> 41 struct __bind_back_t : __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs> { 42 using __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs>::__perfect_forward; 43 }; 44 45 template <class _Fn, class ..._Args, class = enable_if_t< 46 _And< 47 is_constructible<decay_t<_Fn>, _Fn>, 48 is_move_constructible<decay_t<_Fn>>, 49 is_constructible<decay_t<_Args>, _Args>..., 50 is_move_constructible<decay_t<_Args>>... 51 >::value 52 >> 53 _LIBCPP_HIDE_FROM_ABI 54 constexpr auto __bind_back(_Fn&& __f, _Args&&... __args) 55 noexcept(noexcept(__bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)))) 56 -> decltype( __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...))) 57 { return __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)); } 58 59 #endif // _LIBCPP_STD_VER >= 20 60 61 _LIBCPP_END_NAMESPACE_STD 62 63 #endif // _LIBCPP___FUNCTIONAL_BIND_BACK_H 64