From 6867fc5f06c59f01e743930aa69f36c5850fc5e3 Mon Sep 17 00:00:00 2001
From: Nekotekina <nekotekina@gmail.com>
Date: Wed, 23 Oct 2019 21:53:55 +0300
Subject: [PATCH] Revert "Simplify lf_queue<>"

This reverts commit 050e5b4aec533da248478bd5bf7abd0784e5d805.
---
 Utilities/lockless.h | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/Utilities/lockless.h b/Utilities/lockless.h
index 98b8e891af..62b9a08bdd 100644
--- a/Utilities/lockless.h
+++ b/Utilities/lockless.h
@@ -311,16 +311,22 @@ public:
 	}
 };
 
+class lf_queue_base
+{
+protected:
+	atomic_t<std::uintptr_t> m_head = 0;
+};
+
 // Linked list-based multi-producer queue (the consumer drains the whole queue at once)
 template <typename T>
-class lf_queue final
+class lf_queue : public lf_queue_base
 {
-	atomic_t<lf_queue_item<T>*> m_head;
+	using lf_queue_base::m_head;
 
 	// Extract all elements and reverse element order (FILO to FIFO)
 	lf_queue_item<T>* reverse() noexcept
 	{
-		if (auto* head = m_head.load() ? m_head.exchange(nullptr) : nullptr)
+		if (auto* head = m_head.load() ? reinterpret_cast<lf_queue_item<T>*>(m_head.exchange(0)) : nullptr)
 		{
 			if (auto* prev = head->m_link)
 			{
@@ -346,26 +352,26 @@ public:
 
 	~lf_queue()
 	{
-		delete m_head.load();
+		delete reinterpret_cast<lf_queue_item<T>*>(m_head.load());
 	}
 
 	void wait() noexcept
 	{
-		if (m_head == nullptr)
+		if (m_head == 0)
 		{
-			m_head.wait(nullptr);
+			m_head.wait(0);
 		}
 	}
 
 	template <typename... Args>
 	void push(Args&&... args)
 	{
-		auto _old = m_head.load();
-		auto item = new lf_queue_item<T>(_old, std::forward<Args>(args)...);
+		auto  _old = m_head.load();
+		auto* item = new lf_queue_item<T>(reinterpret_cast<lf_queue_item<T>*>(_old), std::forward<Args>(args)...);
 
-		while (!m_head.compare_exchange(_old, item))
+		while (!m_head.compare_exchange(_old, reinterpret_cast<std::uint64_t>(item)))
 		{
-			item->m_link = _old;
+			item->m_link = reinterpret_cast<lf_queue_item<T>*>(_old);
 		}
 
 		if (!_old)