Init enter game

KcpSharp/Base/KcpSendReceiveBufferItemCache.cs

@@ -0,0 +1,68 @@
+#if NEED_LINKEDLIST_SHIM
+using LinkedListOfBufferItem = KcpSharp.NetstandardShim.LinkedList<KcpSharp.KcpSendReceiveBufferItem>;
+using LinkedListNodeOfBufferItem = KcpSharp.NetstandardShim.LinkedListNode<KcpSharp.KcpSendReceiveBufferItem>;
+#else
+using LinkedListNodeOfBufferItem =
+    System.Collections.Generic.LinkedListNode<KianaBH.KcpSharp.Base.KcpSendReceiveBufferItem>;
+using LinkedListOfBufferItem =
+    System.Collections.Generic.LinkedList<KianaBH.KcpSharp.Base.KcpSendReceiveBufferItem>;
+#endif
+
+namespace KianaBH.KcpSharp.Base;
+
+internal struct KcpSendReceiveBufferItemCache
+{
+    private LinkedListOfBufferItem _items;
+    private SpinLock _lock;
+
+    public static KcpSendReceiveBufferItemCache Create()
+    {
+        return new KcpSendReceiveBufferItemCache
+        {
+            _items = new LinkedListOfBufferItem(),
+            _lock = new SpinLock()
+        };
+    }
+
+    public LinkedListNodeOfBufferItem Allocate(in KcpSendReceiveBufferItem item)
+    {
+        var lockAcquired = false;
+        try
+        {
+            _lock.Enter(ref lockAcquired);
+
+            var node = _items.First;
+            if (node is null)
+            {
+                node = new LinkedListNodeOfBufferItem(item);
+            }
+            else
+            {
+                _items.Remove(node);
+                node.ValueRef = item;
+            }
+
+            return node;
+        }
+        finally
+        {
+            if (lockAcquired) _lock.Exit();
+        }
+    }
+
+    public void Return(LinkedListNodeOfBufferItem node)
+    {
+        var lockAcquired = false;
+        try
+        {
+            _lock.Enter(ref lockAcquired);
+
+            node.ValueRef = default;
+            _items.AddLast(node);
+        }
+        finally
+        {
+            if (lockAcquired) _lock.Exit();
+        }
+    }
+}