xref: /openbsd-src/gnu/llvm/libcxx/include/__functional/bind_back.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert // -*- C++ -*-
2*4bdff4beSrobert //===----------------------------------------------------------------------===//
3*4bdff4beSrobert //
4*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
6*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7*4bdff4beSrobert //
8*4bdff4beSrobert //===----------------------------------------------------------------------===//
9*4bdff4beSrobert 
10*4bdff4beSrobert #ifndef _LIBCPP___FUNCTIONAL_BIND_BACK_H
11*4bdff4beSrobert #define _LIBCPP___FUNCTIONAL_BIND_BACK_H
12*4bdff4beSrobert 
13*4bdff4beSrobert #include <__config>
14*4bdff4beSrobert #include <__functional/invoke.h>
15*4bdff4beSrobert #include <__functional/perfect_forward.h>
16*4bdff4beSrobert #include <__utility/forward.h>
17*4bdff4beSrobert #include <__utility/integer_sequence.h>
18*4bdff4beSrobert #include <tuple>
19*4bdff4beSrobert #include <type_traits>
20*4bdff4beSrobert 
21*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22*4bdff4beSrobert #  pragma GCC system_header
23*4bdff4beSrobert #endif
24*4bdff4beSrobert 
25*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
26*4bdff4beSrobert 
27*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
28*4bdff4beSrobert 
29*4bdff4beSrobert template <size_t _NBound, class = make_index_sequence<_NBound>>
30*4bdff4beSrobert struct __bind_back_op;
31*4bdff4beSrobert 
32*4bdff4beSrobert template <size_t _NBound, size_t ..._Ip>
33*4bdff4beSrobert struct __bind_back_op<_NBound, index_sequence<_Ip...>> {
34*4bdff4beSrobert     template <class _Fn, class _BoundArgs, class... _Args>
35*4bdff4beSrobert     _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Fn&& __f, _BoundArgs&& __bound_args, _Args&&... __args) const
36*4bdff4beSrobert         noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...)))
37*4bdff4beSrobert         -> decltype(      _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...))
38*4bdff4beSrobert         { return          _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_BoundArgs>(__bound_args))...); }
39*4bdff4beSrobert };
40*4bdff4beSrobert 
41*4bdff4beSrobert template <class _Fn, class _BoundArgs>
42*4bdff4beSrobert struct __bind_back_t : __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs> {
43*4bdff4beSrobert     using __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs>::__perfect_forward;
44*4bdff4beSrobert };
45*4bdff4beSrobert 
46*4bdff4beSrobert template <class _Fn, class ..._Args, class = enable_if_t<
47*4bdff4beSrobert     _And<
48*4bdff4beSrobert         is_constructible<decay_t<_Fn>, _Fn>,
49*4bdff4beSrobert         is_move_constructible<decay_t<_Fn>>,
50*4bdff4beSrobert         is_constructible<decay_t<_Args>, _Args>...,
51*4bdff4beSrobert         is_move_constructible<decay_t<_Args>>...
52*4bdff4beSrobert     >::value
53*4bdff4beSrobert >>
54*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI
55*4bdff4beSrobert constexpr auto __bind_back(_Fn&& __f, _Args&&... __args)
56*4bdff4beSrobert     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*4bdff4beSrobert     -> decltype(      __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)))
58*4bdff4beSrobert     { return          __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)); }
59*4bdff4beSrobert 
60*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17
61*4bdff4beSrobert 
62*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
63*4bdff4beSrobert 
64*4bdff4beSrobert #endif // _LIBCPP___FUNCTIONAL_BIND_BACK_H
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