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 <__utility/forward.h> 17 #include <type_traits> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 #if _LIBCPP_STD_VER > 17 26 27 struct __bind_front_op { 28 template <class ..._Args> 29 _LIBCPP_HIDE_FROM_ABI 30 constexpr auto operator()(_Args&& ...__args) const 31 noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...))) 32 -> decltype( _VSTD::invoke(_VSTD::forward<_Args>(__args)...)) 33 { return _VSTD::invoke(_VSTD::forward<_Args>(__args)...); } 34 }; 35 36 template <class _Fn, class ..._BoundArgs> 37 struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> { 38 using __perfect_forward<__bind_front_op, _Fn, _BoundArgs...>::__perfect_forward; 39 }; 40 41 template <class _Fn, class... _Args, class = enable_if_t< 42 _And< 43 is_constructible<decay_t<_Fn>, _Fn>, 44 is_move_constructible<decay_t<_Fn>>, 45 is_constructible<decay_t<_Args>, _Args>..., 46 is_move_constructible<decay_t<_Args>>... 47 >::value 48 >> 49 _LIBCPP_HIDE_FROM_ABI 50 constexpr auto bind_front(_Fn&& __f, _Args&&... __args) { 51 return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...); 52 } 53 54 #endif // _LIBCPP_STD_VER > 17 55 56 _LIBCPP_END_NAMESPACE_STD 57 58 #endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H 59