llvm-project/libcxx/include/__functional/bind_front.h

59 lines
1.9 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FUNCTIONAL_BIND_FRONT_H
#define _LIBCPP___FUNCTIONAL_BIND_FRONT_H
#include <__config>
#include <__functional/perfect_forward.h>
#include <__functional/invoke.h>
#include <type_traits>
#include <utility>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
struct __bind_front_op {
template <class ..._Args>
_LIBCPP_HIDE_FROM_ABI
constexpr auto operator()(_Args&& ...__args) const
noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
-> decltype( _VSTD::invoke(_VSTD::forward<_Args>(__args)...))
{ return _VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
};
template <class _Fn, class ..._BoundArgs>
struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> {
using __perfect_forward<__bind_front_op, _Fn, _BoundArgs...>::__perfect_forward;
};
template <class _Fn, class... _Args, class = _EnableIf<
_And<
is_constructible<decay_t<_Fn>, _Fn>,
is_move_constructible<decay_t<_Fn>>,
is_constructible<decay_t<_Args>, _Args>...,
is_move_constructible<decay_t<_Args>>...
>::value
>>
_LIBCPP_HIDE_FROM_ABI
constexpr auto bind_front(_Fn&& __f, _Args&&... __args) {
return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
}
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H