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fennec/include/fennec/lang/function.h
2025-12-19 20:58:19 -05:00

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// =====================================================================================================================
// fennec, a free and open source game engine
// Copyright © 2025 Medusa Slockbower
//
// This program 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 program 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 <https://www.gnu.org/licenses/>.
// =====================================================================================================================
///
/// \file function.h
/// \brief
///
///
/// \details
/// \author Medusa Slockbower
///
/// \copyright Copyright © 2025 Medusa Slockbower ([GPLv3](https://www.gnu.org/licenses/gpl-3.0.en.html))
///
///
#ifndef FENNEC_LANG_FUNCTION_H
#define FENNEC_LANG_FUNCTION_H
#include <fennec/lang/types.h>
#include <fennec/lang/assert.h>
#include <fennec/lang/utility.h>
#include <fennec/lang/detail/_function.h>
namespace fennec
{
///
/// \brief a class capable of holding a function or non-capturing lambda
template<typename> class function;
///
/// \brief a class capable of holding a function or non-capturing lambda
/// \tparam ReturnT The return type of the function
/// \tparam ArgsT The argument types of the function
template<typename ReturnT, typename...ArgsT>
class function<ReturnT(ArgsT...)> {
public:
///
/// \brief default constructor
constexpr function() noexcept
: call(nullptr) {
}
///
/// \brief destructor
constexpr ~function() = default;
///
/// \brief copy constructor
/// \param func the function to copy
constexpr function(const function& func) noexcept = default;
///
/// \brief move constructor
/// \param func the function to take ownership of
constexpr function(function&& func) noexcept = default;
///
/// \brief function constructor
/// \param func the function to capture
constexpr function(ReturnT (*func)(ArgsT...))
: call(func) {
}
///
/// \brief null constructor
constexpr function(nullptr_t) noexcept : function() {}
///
/// \brief copy assignment
/// \param func the function to copy
/// \returns a reference to self
constexpr function& operator=(const function& func) = default;
///
/// \brief move assignment
/// \param func the function to capture
/// \returns a reference to self
constexpr function& operator=(function&& func) = default;
///
/// \brief null assignment
/// \returns a reference to self
constexpr function& operator=(nullptr_t) {
call = nullptr;
return *this;
}
///
/// \brief function assignment
/// \param func the function to capture
/// \returns a reference to self
constexpr function& operator=(ReturnT (*func)(ArgsT...)) {
call = func;
return *this;
}
///
/// \brief implicit bool check
/// \returns \f$true\f$ if a function is captured, \f$false\f$ otherwise
constexpr operator bool() const noexcept {
return call != nullptr;
}
///
/// \brief function call operator
/// \param args the arguments to call the function with
/// \returns the result of the function call
ReturnT operator()(ArgsT...args) const noexcept {
assertf(call != nullptr, "Attempted to call a null function object!");
return call(fennec::forward<ArgsT>(args)...);
}
private:
ReturnT (*call)(ArgsT&&...) { nullptr };
};
}
#endif // FENNEC_LANG_FUNCTION_H