From b05e710bfee12e3c81a44582a228572707391b76 Mon Sep 17 00:00:00 2001
From: Ludovic 'Archivist' Lagouardette <ludovic@nekoit.xyz>
Date: Wed, 31 Mar 2021 17:02:23 +0200
Subject: [PATCH] Better pointers

---
 include/gp/memory.hpp   |   2 +
 include/gp/pointers.hpp | 225 ++++++++++++++++------------------------
 2 files changed, 89 insertions(+), 138 deletions(-)

diff --git a/include/gp/memory.hpp b/include/gp/memory.hpp
index db28980..1a9b13b 100644
--- a/include/gp/memory.hpp
+++ b/include/gp/memory.hpp
@@ -2,6 +2,8 @@
 
 #include "gp_config.hpp"
 
+#include "gp/algorithm/move.hpp"
+#include "gp/allocator/allocator.hpp"
 #include "gp/exception.hpp"
 
 #include <type_traits>
diff --git a/include/gp/pointers.hpp b/include/gp/pointers.hpp
index 38afae1..73dd08a 100644
--- a/include/gp/pointers.hpp
+++ b/include/gp/pointers.hpp
@@ -5,183 +5,132 @@
 #include "gp/buffer.hpp"
 #include "gp/function.hpp"
 
-template<typename T, typename allocator_t = void>
-class unique_ptr;
+
 
 template<typename T>
-class unique_ptr<T, void> {
-	T* ptr;
-	gp::function<bool(T*)> deallocator;
-public:
-	unique_ptr()
-	: ptr{nullptr}
-	{}
+class unique_ptr {
+	T* data;
+	gp::allocator const& owner;
 
-	template<typename deal>
-	unique_ptr(T* _ptr, deal func)
-	: ptr{_ptr}
-	, deallocator{func}
+	unique_ptr(T* _data, gp::allocator const& _owner)
+	: data(data)
+	, owner(_owner)
 	{}
 
-	unique_ptr(unique_ptr&) = delete;
-	
-	unique_ptr(unique_ptr&& oth)
-	: ptr{oth.ptr}
-	, deallocator{oth.deallocator}
-	{
-		oth.ptr = nullptr;
-	}
-
-	void operator=(unique_ptr&) = delete;
-
-	void operator=(unique_ptr&& oth) {
-		ptr = oth.ptr;
-		deallocator = oth.deallocator;
-		oth.ptr = nullptr;
-	}
-
-	operator bool() {
-		return ptr != nullptr;
-	}
-
-	T* operator->() {
-		return ptr;
-	}
-
-	T* operator*() {
-		return ptr;
-	}
-
-	~unique_ptr() {
-		if(ptr) {
-			ptr->~T();
-			gp_config::assertion(deallocator(ptr), "freeing unique_ptr failed");
+	void dirty_clear() {
+		if(data) {
+			data->~T();
+			owner.deallocate(data);
 		}
 	}
-};
-
-template<typename T, typename allocator>
-class unique_ptr<T, gp::reference_wrapper<allocator>>{
-	T* ptr;
-	gp::reference_wrapper<allocator> ref;
 public:
-	unique_ptr()
-	: ptr{nullptr}
-	{}
+	template<typename ...U>
+	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 ...Args>
-	unique_ptr(Args ...args, allocator& _ref)
-	: ref{_ref} {
-		auto p = ref.get().allocate(sizeof(T));
-		if(p)
-		{
-			ptr = new(p) T(args...);
-		} else {
-			ptr = nullptr;
-		}
+	T& operator->() {
+		return *data;
 	}
 
-	unique_ptr(T* _ptr, allocator& _ref)
-	: ptr{_ptr}
-	, ref{_ref}
-	{}
+	T& operator*() {
+		return *data;
+	}
 
 	unique_ptr(unique_ptr&) = delete;
-	
+
 	unique_ptr(unique_ptr&& oth)
-	: ptr{oth.ptr}
-	, ref{oth.ref}
+	: data(oth.data)
+	, owner(oth.owner)
 	{
-		oth.ptr = nullptr;
-	}
-
-	void operator=(unique_ptr&) = delete;
-
-	void operator=(unique_ptr&& oth) {
-		ptr = oth.ptr;
-		ref = oth.ref; 
-		oth.ptr = nullptr;
+		oth.data = nullptr;
 	}
 
-	operator bool() {
-		return ptr != nullptr;
-	}
-
-	T* operator->() {
-		return ptr;
-	}
+	unique_ptr& operator=(unique_ptr&) = delete;
 
-	T* operator*() {
-		return ptr;
+	unique_ptr& operator=(unique_ptr&& oth) {
+		dirty_clear();
+		data = oth.data;
+		owner = oth.owner;
 	}
 
 	~unique_ptr() {
-		if(ptr) {
-			ptr->~T();
-			gp_config::assertion(ref.get().deallocate(ptr), "freeing unique_ptr failed");
-		}
+		dirty_clear();
 	}
 };
 
-template<typename T, typename allocator>
-class unique_ptr{
-	T* ptr;
-	allocator alloc;
-public:
-	unique_ptr()
-	: ptr{nullptr}
-	{}
-
-	unique_ptr(T* _ptr, allocator _alloc = allocator{})
-	: ptr{_ptr}
-	, alloc{_alloc}
+template<typename T>
+class shared_ptr {
+	T* data;
+	std::atomic_int* refcounter;
+	gp::allocator const& owner;
+
+	shared_ptr(T* _data, gp::allocator const& _owner)
+	: data(data)
+	, owner(_owner)
 	{}
 
-	template<typename ...Args>
-	unique_ptr(Args ...args, allocator _alloc = allocator{})
-	: alloc{_alloc} {
-		auto p = alloc.allocate(sizeof(T));
-		if(p)
-		{
-			ptr = new(p) T(args...);
-		} else {
-			ptr = nullptr;
+	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>
+	shared_ptr make(gp::allocator& owner, U&&... args) {
+		auto ptr = owner.allocate(sizeof(T));
+		auto shared_atomic = owner.allocate(sizeof(std::atomic_int));
+		refcounter = new(shared_atomic) std::atomic_int();
+		refcounter->store(1);
+		return shared_ptr(new(ptr) T(gp::forward<U>(args)...), owner);
+	}
 
-	unique_ptr(unique_ptr&) = delete;
-	
-	unique_ptr(unique_ptr&& oth)
-	: ptr{oth.ptr}
-	, alloc{oth.alloc}
-	{
-		oth.ptr = nullptr;
+	T& operator->() {
+		return *data;
 	}
 
-	void operator=(unique_ptr&) = delete;
+	T& operator*() {
+		return *data;
+	}
 
-	void operator=(unique_ptr&& oth) {
-		ptr = oth.ptr;
-		alloc = oth.alloc; 
-		oth.ptr = nullptr;
+	shared_ptr(shared_ptr& oth) {
+		oth.refcounter->fetch_add(1, std::memory_order::acquire);
+		
+		data = oth.data;
+		refcounter = oth.refcounter;
+		owner = oth.owner;		
 	}
 
-	operator bool() {
-		return ptr != nullptr;
+	shared_ptr(shared_ptr&& oth)
+	: data(oth.data)
+	, owner(oth.owner)
+	{
+		oth.data = nullptr;
+		oth.refcounter = nullptr;
 	}
 
-	T* operator->() {
-		return ptr;
+	shared_ptr& operator=(shared_ptr& oth) {
+		dirty_clear();
+		(*oth.refcounter)++;
+		
+		data = oth.data;
+		refcounter = oth.refcounter;
+		owner = oth.owner;	
 	}
 
-	T* operator*() {
-		return ptr;
+	shared_ptr& operator=(shared_ptr&& oth) {
+		dirty_clear();
+		data = oth.data;
+		owner = oth.owner;
 	}
 
-	~unique_ptr() {
-		if(ptr) {
-			ptr->~T();
-			gp_config::assertion(alloc.deallocate(ptr), "freeing unique_ptr failed");
-		}
+	~shared_ptr() {
+		dirty_clear();
 	}
 };
\ No newline at end of file