General Purpose library for Freestanding C++ and POSIX systems
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#pragma once
#include "gp/functional/bind_front.hpp"
#include "gp/algorithms/move.hpp"
#include "gp/containers/buffer.hpp"
#include "gp/functional/function.hpp"
#include <atomic>
#include <concepts>
namespace gp {
template<typename T>
class unique_ptr {
T* data;
gp::allocator& owner;
void dirty_clear() {
if(data) {
data->~T();
owner.deallocate(data);
}
}
public:
unique_ptr(T* _data, gp::allocator& _owner)
: data(_data)
, owner(_owner)
{}
template<typename ...U>
static unique_ptr make(gp::allocator& owner, U&&... args) {
auto ptr = owner.allocate(sizeof(T));
return unique_ptr(new(ptr) T(gp::forward<U>(args)...), owner);
}
template<typename U>
unique_ptr<U> cast() {
auto save = data;
data = nullptr;
return unique_ptr<U>(save, owner);
}
T* operator->() {
return data;
}
T& operator*() {
return *data;
}
operator bool() {
return data != nullptr;
}
unique_ptr(unique_ptr&) = delete;
unique_ptr(unique_ptr&& oth)
: data(oth.data)
, owner(oth.owner)
{
oth.data = nullptr;
}
unique_ptr& operator=(unique_ptr&) = delete;
unique_ptr& operator=(unique_ptr&& oth) {
dirty_clear();
data = oth.data;
owner = oth.owner;
}
~unique_ptr() {
dirty_clear();
}
};
template<typename T>
class shared_ptr {
T* data;
std::atomic_int* refcounter;
gp::allocator& owner;
shared_ptr(T* _data, gp::allocator& _owner)
: data(_data)
, refcounter((std::atomic_int*)owner.allocate(sizeof(std::atomic_int)))
, owner(_owner)
{
refcounter->store(1);
}
shared_ptr(T* _data, std::atomic_int* refctr, gp::allocator& _owner)
: data(_data)
, refcounter(refctr)
, owner(_owner)
{
refcounter->store(1);
}
void dirty_clear() {
if(!refcounter) return;
if(refcounter->fetch_sub(1, std::memory_order::acq_rel) == 0) {
if(data) {
data->~T();
owner.deallocate(refcounter);
owner.deallocate(data);
}
}
}
public:
template<typename ...U>
static shared_ptr make(gp::allocator& owner, U&&... args) {
auto ptr = owner.allocate(sizeof(T));
return shared_ptr(new(ptr) T(gp::forward<U>(args)...), owner);
}
template<typename U>
shared_ptr<U> cast() {
return shared_ptr<U>(data, refcounter, owner);
}
T* operator->() {
return data;
}
T& operator*() {
return *data;
}
operator bool() {
return data != nullptr;
}
shared_ptr(shared_ptr& oth) {
oth.refcounter->fetch_add(1, std::memory_order::acquire);
data = oth.data;
refcounter = oth.refcounter;
owner = oth.owner;
}
shared_ptr(shared_ptr&& oth)
: data(oth.data)
, owner(oth.owner)
{
oth.data = nullptr;
oth.refcounter = nullptr;
}
shared_ptr& operator=(shared_ptr& oth) {
dirty_clear();
(*oth.refcounter)++;
data = oth.data;
refcounter = oth.refcounter;
owner = oth.owner;
}
shared_ptr& operator=(shared_ptr&& oth) {
dirty_clear();
data = oth.data;
owner = oth.owner;
}
~shared_ptr() {
dirty_clear();
}
};
template<std::copyable T>
struct resource_traits {
using identifier = uint64_t;
static constexpr bool create_if_not_exist = false;
static T* create(const identifier&, gp::allocator&);
static T* retrieve(const identifier&, gp::allocator&);
static bool imprint(const identifier&, const T& value);
static bool annihilate(const identifier&);
};
template<std::copyable T>
requires std::copyable<typename resource_traits<T>::identifier>
class resource_ptr
{
typename resource_traits<T>::identifier _identifier;
gp::allocator& _alloc;
T* value = nullptr;
operator T&() {
if(!value) {
value = resource_traits<T>::retrieve(_identifier, _alloc);
}
if(value) return *value;
else if constexpr (resource_traits<T>::create_if_not_exist) {
value = resource_traits<T>::create(_identifier, _alloc);
if(value) return *value;
}
gp_config::assertion(false, "unavailable resource lead to crash");
}
gp::optional<T&> read() {
if(!value) {
value = resource_traits<T>::retrieve(_identifier, _alloc);
}
if(value) return *value;
else if constexpr (resource_traits<T>::create_if_not_exist) {
value = resource_traits<T>::create(_identifier, _alloc);
if(value) return *value;
}
return gp::nullopt;
}
gp::optional<T&> force_read() {
value = resource_traits<T>::retrieve(_identifier, _alloc);
if(value) return *value;
return gp::nullopt;
}
template<typename U>
requires std::is_base_of_v<T, U>
gp::optional<T&> operator=(U& new_value) {
if(resource_traits<T>::imprint(_identifier, new_value)) {
if(value) {
value->~T();
gp_config::assertion(_alloc.deallocate((void*)value), "deallocation failure during exchange");
}
value = _alloc.allocate(sizeof(U));
gp_config::assertion(value != nullptr, "could not allocate during resource transcription");
new(value) U(new_value);
return *value;
}
return gp::nullopt;
}
template<typename U>
requires std::is_base_of_v<T, U>
gp::optional<T&> operator=(const U& new_value) {
if(resource_traits<T>::imprint(_identifier, new_value)) {
if(value) {
value->~T();
gp_config::assertion(_alloc.deallocate((void*)value), "deallocation failure during exchange");
}
value = _alloc.allocate(sizeof(U));
gp_config::assertion(value != nullptr, "could not allocate during resource transcription");
new(value) U(new_value);
return *value;
}
return gp::nullopt;
}
template<>
gp::optional<T&> operator=<gp::nullopt_t>(const gp::nullopt_t) {
if(resource_traits<T>::annihilate(_identifier)) {
if(value) {
value->~T();
gp_config::assertion(_alloc.deallocate((void*)value), "deallocation failure during exchange");
}
value = nullptr;
}
return gp::nullopt;
}
};
}