From 5b6427dde0bb8e3b466793243bbfc185f4739ac6 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Mon, 14 Mar 2022 14:13:54 +0100
Subject: refactor: implement & use shared ptr

---
 src/common/memory/shared_ptr.hpp |  44 +++++++++++
 src/common/memory/shared_ptr.tpp | 153 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 197 insertions(+)
 create mode 100644 src/common/memory/shared_ptr.hpp
 create mode 100644 src/common/memory/shared_ptr.tpp

(limited to 'src/common')

diff --git a/src/common/memory/shared_ptr.hpp b/src/common/memory/shared_ptr.hpp
new file mode 100644
index 0000000..7e8a910
--- /dev/null
+++ b/src/common/memory/shared_ptr.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <stddef.h>
+
+namespace common
+{
+template <class Target>
+class SharedPtr
+{
+public:
+	SharedPtr() noexcept;
+	SharedPtr(nullptr_t) noexcept; // NOLINT(google-explicit-constructor)
+
+	explicit SharedPtr(Target *target) noexcept;
+
+	SharedPtr(const SharedPtr &shared_ptr) noexcept;
+
+	SharedPtr(SharedPtr &&shared_ptr) noexcept;
+
+	~SharedPtr() noexcept;
+
+	[[nodiscard]] unsigned int reference_cnt() const noexcept;
+
+	[[nodiscard]] bool is_disposable() const noexcept;
+
+	SharedPtr &operator=(const SharedPtr &rhs) noexcept;
+
+	SharedPtr &operator=(SharedPtr &&rhs) noexcept;
+
+	Target &operator*() const noexcept;
+	Target *operator->() const noexcept;
+
+private:
+	Target *_target = nullptr;
+
+	unsigned int *_reference_cnt;
+};
+
+template <typename Target, typename... Args>
+SharedPtr<Target> make_shared(Args &&...args) noexcept;
+
+} // namespace common
+
+#include "shared_ptr.tpp"
diff --git a/src/common/memory/shared_ptr.tpp b/src/common/memory/shared_ptr.tpp
new file mode 100644
index 0000000..d9b57c3
--- /dev/null
+++ b/src/common/memory/shared_ptr.tpp
@@ -0,0 +1,153 @@
+#pragma once
+
+#include "shared_ptr.hpp"
+
+#include "common/memory.hpp"
+
+#include <stdlib.h>
+
+namespace common
+{
+
+template <class Target>
+SharedPtr<Target>::SharedPtr() noexcept
+	: _reference_cnt(malloc_s<unsigned int>(sizeof(unsigned int)))
+{
+	(*_reference_cnt) = 0;
+}
+
+template <class Target>
+SharedPtr<Target>::SharedPtr(nullptr_t) noexcept
+	: _reference_cnt(malloc_s<unsigned int>(sizeof(unsigned int)))
+{
+	(*_reference_cnt) = 0;
+}
+
+template <class Target>
+SharedPtr<Target>::SharedPtr(Target *target) noexcept
+	: _target(target), _reference_cnt(malloc_s<unsigned int>(sizeof(unsigned int)))
+{
+	(*_reference_cnt) = 0;
+}
+
+/**
+ * Copy constructor
+ */
+template <class Target>
+SharedPtr<Target>::SharedPtr(const SharedPtr &shared_ptr) noexcept
+	: _target(shared_ptr._target), _reference_cnt(shared_ptr._reference_cnt)
+{
+	(*_reference_cnt)++;
+}
+
+/**
+ * Move constructor
+ */
+template <class Target>
+SharedPtr<Target>::SharedPtr(SharedPtr &&shared_ptr) noexcept
+	: _target(shared_ptr._target), _reference_cnt(shared_ptr._reference_cnt)
+{
+	shared_ptr._target = nullptr;
+}
+
+template <class Target>
+SharedPtr<Target>::~SharedPtr() noexcept
+{
+	if ((*_reference_cnt) != 0U)
+	{
+		(*_reference_cnt)--;
+	}
+
+	if ((*_reference_cnt) == 0U)
+	{
+		delete _target;
+		free(_reference_cnt);
+		_reference_cnt = nullptr;
+	}
+}
+
+template <class Target>
+unsigned int SharedPtr<Target>::reference_cnt() const noexcept
+{
+	if (_reference_cnt == nullptr)
+	{
+		return 0;
+	}
+
+	return *_reference_cnt;
+}
+
+template <class Target>
+bool SharedPtr<Target>::is_disposable() const noexcept
+{
+	return _reference_cnt == nullptr || (*_reference_cnt) == 0U;
+}
+
+/**
+ * Copy assignment operator
+ */
+template <class Target>
+SharedPtr<Target> &SharedPtr<Target>::operator=(const SharedPtr &rhs) noexcept
+{
+	if (&rhs != this)
+	{
+		if (is_disposable())
+		{
+			delete _target;
+			free(_reference_cnt);
+		}
+
+		_target = nullptr;
+		_target = rhs._target;
+
+		_reference_cnt = nullptr;
+		_reference_cnt = rhs._reference_cnt;
+		(*_reference_cnt)++;
+	}
+
+	return *this;
+}
+
+/**
+ * Move assignment operator
+ */
+template <class Target>
+SharedPtr<Target> &SharedPtr<Target>::operator=(SharedPtr &&rhs) noexcept
+{
+	if (&rhs != this)
+	{
+		if (is_disposable())
+		{
+			delete _target;
+			free(_reference_cnt);
+		}
+
+		_target = rhs._target;
+		rhs._target = nullptr;
+
+		_reference_cnt = rhs._reference_cnt;
+		rhs._reference_cnt = nullptr;
+	}
+
+	return *this;
+}
+
+template <class Target>
+Target &SharedPtr<Target>::operator*() const noexcept
+{
+	return *(_target);
+}
+
+template <class Target>
+Target *SharedPtr<Target>::operator->() const noexcept
+{
+	return _target;
+}
+
+template <class Target, typename... Args>
+SharedPtr<Target> make_shared(Args &&...args) noexcept
+{
+	return SharedPtr<Target>(new Target(args...));
+}
+
+} // namespace common
-- 
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