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 constexpr auto operator()(_Args&&... __args) const 34 noexcept(noexcept(std::invoke(std::forward<_Args>(__args)...))) 35 -> decltype(std::invoke(std::forward<_Args>(__args)...)) { 36 return std::invoke(std::forward<_Args>(__args)...); 37 } 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> 46 requires is_constructible_v<decay_t<_Fn>, _Fn> && is_move_constructible_v<decay_t<_Fn>> && 47 (is_constructible_v<decay_t<_Args>, _Args> && ...) && (is_move_constructible_v<decay_t<_Args>> && ...) 48 _LIBCPP_HIDE_FROM_ABI constexpr auto bind_front(_Fn&& __f, _Args&&... __args) { 49 return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(std::forward<_Fn>(__f), std::forward<_Args>(__args)...); 50 } 51 52 #endif // _LIBCPP_STD_VER >= 20 53 54 _LIBCPP_END_NAMESPACE_STD 55 56 #endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H 57