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_COMPOSE_H 11*4bdff4beSrobert #define _LIBCPP___FUNCTIONAL_COMPOSE_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 <type_traits> 18*4bdff4beSrobert 19*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20*4bdff4beSrobert # pragma GCC system_header 21*4bdff4beSrobert #endif 22*4bdff4beSrobert 23*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD 24*4bdff4beSrobert 25*4bdff4beSrobert #if _LIBCPP_STD_VER > 17 26*4bdff4beSrobert 27*4bdff4beSrobert struct __compose_op { 28*4bdff4beSrobert template<class _Fn1, class _Fn2, class ..._Args> 29*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI 30*4bdff4beSrobert constexpr auto operator()(_Fn1&& __f1, _Fn2&& __f2, _Args&&... __args) const 31*4bdff4beSrobert noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)))) 32*4bdff4beSrobert -> decltype( _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...))) 33*4bdff4beSrobert { return _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)); } 34*4bdff4beSrobert }; 35*4bdff4beSrobert 36*4bdff4beSrobert template <class _Fn1, class _Fn2> 37*4bdff4beSrobert struct __compose_t : __perfect_forward<__compose_op, _Fn1, _Fn2> { 38*4bdff4beSrobert using __perfect_forward<__compose_op, _Fn1, _Fn2>::__perfect_forward; 39*4bdff4beSrobert }; 40*4bdff4beSrobert 41*4bdff4beSrobert template <class _Fn1, class _Fn2> 42*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI 43*4bdff4beSrobert constexpr auto __compose(_Fn1&& __f1, _Fn2&& __f2) 44*4bdff4beSrobert noexcept(noexcept(__compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)))) 45*4bdff4beSrobert -> decltype( __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2))) 46*4bdff4beSrobert { return __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)); } 47*4bdff4beSrobert 48*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17 49*4bdff4beSrobert 50*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD 51*4bdff4beSrobert 52*4bdff4beSrobert #endif // _LIBCPP___FUNCTIONAL_COMPOSE_H 53