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_FRONT_H 11 #define _LIBCPP___FUNCTIONAL_BIND_FRONT_H 12 13 #include <__config> 14 #include <__functional/invoke.h> 15 #include <__functional/perfect_forward.h> 16 #include <__type_traits/conjunction.h> 17 #include <__type_traits/decay.h> 18 #include <__type_traits/enable_if.h> 19 #include <__type_traits/is_constructible.h> 20 #include <__type_traits/is_move_constructible.h> 21 #include <__utility/forward.h> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 29 #if _LIBCPP_STD_VER >= 20 30 31 struct __bind_front_op { 32 template <class ..._Args> 33 _LIBCPP_HIDE_FROM_ABI 34 constexpr auto operator()(_Args&& ...__args) const 35 noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...))) 36 -> decltype( _VSTD::invoke(_VSTD::forward<_Args>(__args)...)) 37 { return _VSTD::invoke(_VSTD::forward<_Args>(__args)...); } 38 }; 39 40 template <class _Fn, class ..._BoundArgs> 41 struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> { 42 using __perfect_forward<__bind_front_op, _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_front(_Fn&& __f, _Args&&... __args) { 55 return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...); 56 } 57 58 #endif // _LIBCPP_STD_VER >= 20 59 60 _LIBCPP_END_NAMESPACE_STD 61 62 #endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H 63