ardupilot/libraries/AP_HAL/utility/functor.h

91 lines
2.6 KiB
C++

/*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <type_traits>
#define FUNCTOR_TYPEDEF(name, rettype, ...) \
typedef Functor<rettype, ## __VA_ARGS__> name
#define FUNCTOR_DECLARE(name, rettype, ...) \
Functor<rettype, ## __VA_ARGS__> name
#define FUNCTOR_BIND(obj, func, rettype, ...) \
Functor<rettype, ## __VA_ARGS__>::bind<std::remove_reference<decltype(*obj)>::type, func>(obj)
#define FUNCTOR_BIND_MEMBER(func, rettype, ...) \
Functor<rettype, ## __VA_ARGS__>::bind<std::remove_reference<decltype(*this)>::type, func>(this)
template <class RetType, class... Args>
class Functor
{
public:
constexpr Functor(void *obj, RetType (*method)(void *obj, Args...))
: _obj(obj)
, _method(method)
{
}
// Allow to construct an empty Functor
constexpr Functor(decltype(nullptr))
: Functor(nullptr, nullptr) { }
constexpr Functor()
: Functor(nullptr, nullptr) { }
// Call the method on the obj this Functor is bound to
RetType operator()(Args... args) const
{
return _method(_obj, args...);
}
// Compare if the two Functors are calling the same method in the same
// object
inline bool operator==(const Functor<RetType, Args...>& rhs)
{
return _obj == rhs._obj && _method == rhs._method;
}
inline bool operator!=(const Functor<RetType, Args...>& rhs)
{
return _obj != rhs._obj || _method != rhs._method;
}
// Allow to check if there's a method set in the Functor
explicit operator bool() const
{
return _method != nullptr;
}
template<class T, RetType (T::*method)(Args...)>
static constexpr Functor bind(T *obj)
{
return { obj, method_wrapper<T, method> };
}
private:
void *_obj;
RetType (*_method)(void *obj, Args...);
template<class T, RetType (T::*method)(Args...)>
static RetType method_wrapper(void *obj, Args... args)
{
T *t = static_cast<T*>(obj);
return (t->*method)(args...);
}
};