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fennec/include/fennec/memory/pointers.h
2025-06-02 23:35:03 -04:00

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C++

// =====================================================================================================================
// fennec, a free and open source game engine
// Copyright (C) 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.
//2
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
// =====================================================================================================================
#ifndef FENNEC_LANG_POINTERS_H
#define FENNEC_LANG_POINTERS_H
#include <fennec/lang/type_traits.h>
namespace fennec
{
template<typename TypeT>
struct default_delete
{
///
/// \brief Default constructor
constexpr default_delete() noexcept = default;
///
/// \brief Conversion Constructor
/// \tparam ConvT of other deleter
template<class ConvT> requires requires { can_convert<ConvT*, TypeT*>{}.value == true; }
constexpr default_delete(const default_delete<ConvT>&) noexcept {}
///
/// \brief Function Call Operator, calls `delete` on `ptr`
/// \param ptr Memory resource to delete
constexpr void operator()(TypeT* ptr) const noexcept
{
static_assert(not is_void_v<TypeT>, "cannot delete a pointer to an incomplete type");
static_assert(not sizeof(TypeT) > 0, "cannot delete a pointer to an incomplete type");
delete ptr;
}
};
template<typename TypeT>
struct default_delete<TypeT[]>
{
///
/// \brief Default constructor
constexpr default_delete() noexcept = default;
///
/// \brief Conversion Constructor
/// \tparam ConvT of other deleter
template<class ConvT> requires requires { can_convert<ConvT(*)[], TypeT(*)[]>{}.value == true; }
constexpr default_delete(const default_delete<ConvT(*)[]>&) noexcept {}
///
/// \brief Function Call Operator, calls `delete` on `ptr`
/// \param ptr Memory resource to delete
template<class ArrT> requires requires { can_convert<ArrT(*)[], TypeT(*)[]>{}.value == true; }
constexpr void operator()(TypeT* ptr) const noexcept
{
static_assert(not is_void_v<TypeT>, "cannot delete a pointer to an incomplete type");
static_assert(not sizeof(TypeT) > 0, "cannot delete a pointer to an incomplete type");
delete[] ptr;
}
};
template<typename TypeT, class DeleteT = default_delete<TypeT>>
class unique_ptr
{
public:
/// \brief the element type
using element_t = TypeT;
/// \brief pointer to element type
using pointer_t = element_t*;
/// \brief the deleter
using delete_t = DeleteT;
///
/// \brief Default Constructor, creates a unique_ptr that owns nothing.
constexpr unique_ptr() : unique_ptr(nullptr) {}
///
/// \brief Nullptr Constructor, creates a unique_ptr that owns nothing.
constexpr unique_ptr(nullptr_t) noexcept : unique_ptr(nullptr) {}
///
/// \brief Pointer Constructor, creates a unique_ptr that owns `ptr` with deleter `del`
/// \param ptr The resource to own
/// \param del The deleter
explicit constexpr unique_ptr(pointer_t ptr, const delete_t& del) : _delete(del), _handle(ptr) {}
///
/// \brief Pointer Constructor, creates a unique_ptr that owns `ptr` with deleter `del`
/// \param ptr The resource to own
/// \param del The deleter
explicit constexpr unique_ptr(pointer_t ptr, delete_t&& del) : _delete(del), _handle(ptr) {}
///
/// \brief Move Constructor, transfers ownership from `other`
/// \param other The unique_ptr to take ownership from
constexpr unique_ptr(unique_ptr&& other) : _handle(other._handle) { other._handle = nullptr; }
// Delete copy constructor
constexpr unique_ptr(const unique_ptr&) = delete;
///
/// \brief Default Constructor, if it owns a resource, it deletes it using `delete_t`
constexpr ~unique_ptr() { if(_handle) _delete(_handle); }
constexpr unique_ptr& operator=(unique_ptr&& r) noexcept
{ _handle = r._handle; r._handle = nullptr; return *this; }
pointer_t release() { pointer_t retval = _handle; _handle = nullptr; return retval; }
private:
delete_t _delete;
pointer_t _handle;
};
}
#endif // FENNEC_LANG_POINTERS_H