1 files changed, 164 insertions, 0 deletions
diff --git a/ChocolArm64/ATranslatorCache.cs b/ChocolArm64/ATranslatorCache.cs
new file mode 100644
index 00000000..e34cc397
--- /dev/null
+++ b/ChocolArm64/ATranslatorCache.cs
@@ -0,0 +1,164 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Threading;
+
+namespace ChocolArm64
+{
+    class ATranslatorCache
+    {
+        private const int MaxTotalSize          = 2 * 1024 * 256;
+        private const int MaxTimeDelta          = 30000;
+        private const int MinCallCountForUpdate = 1000;
+
+        private class CacheBucket
+        {
+            public ATranslatedSub Subroutine { get; private set; }
+
+            public LinkedListNode<long> Node { get; private set; }
+
+            public int CallCount { get; set; }
+
+            public int Size { get; private set; }
+
+            public int Timestamp { get; private set; }
+
+            public CacheBucket(ATranslatedSub Subroutine, LinkedListNode<long> Node, int Size)
+            {
+                this.Subroutine = Subroutine;
+                this.Size       = Size;
+
+                UpdateNode(Node);
+            }
+
+            public void UpdateNode(LinkedListNode<long> Node)
+            {
+                this.Node = Node;
+
+                Timestamp = Environment.TickCount;
+            }
+        }
+
+        private ConcurrentDictionary<long, CacheBucket> Cache;
+
+        private LinkedList<long> SortedCache;
+
+        private int TotalSize;
+
+        public ATranslatorCache()
+        {
+            Cache = new ConcurrentDictionary<long, CacheBucket>();
+
+            SortedCache = new LinkedList<long>();
+        }
+
+        public void AddOrUpdate(long Position, ATranslatedSub Subroutine, int Size)
+        {
+            ClearCacheIfNeeded();
+
+            TotalSize += Size;
+
+            lock (SortedCache)
+            {
+                LinkedListNode<long> Node = SortedCache.AddLast(Position);
+
+                CacheBucket NewBucket = new CacheBucket(Subroutine, Node, Size);
+
+                Cache.AddOrUpdate(Position, NewBucket, (Key, Bucket) =>
+                {
+                    TotalSize -= Bucket.Size;
+
+                    SortedCache.Remove(Bucket.Node);
+
+                    return NewBucket;
+                });
+            }
+        }
+
+        public bool HasSubroutine(long Position)
+        {
+            return Cache.ContainsKey(Position);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool TryGetSubroutine(long Position, out ATranslatedSub Subroutine)
+        {
+            if (Cache.TryGetValue(Position, out CacheBucket Bucket))
+            {
+                if (Bucket.CallCount++ > MinCallCountForUpdate)
+                {
+                    if (Monitor.TryEnter(SortedCache))
+                    {
+                        try
+                        {
+                            Bucket.CallCount = 0;
+
+                            SortedCache.Remove(Bucket.Node);
+
+                            Bucket.UpdateNode(SortedCache.AddLast(Position));
+                        }
+                        finally
+                        {
+                            Monitor.Exit(SortedCache);
+                        }
+                    }
+                }
+
+                Subroutine = Bucket.Subroutine;
+
+                return true;
+            }
+
+            Subroutine = default(ATranslatedSub);
+
+            return false;
+        }
+
+        private void ClearCacheIfNeeded()
+        {
+            int Timestamp = Environment.TickCount;
+
+            while (TotalSize > MaxTotalSize)
+            {
+                lock (SortedCache)
+                {
+                    LinkedListNode<long> Node = SortedCache.First;
+
+                    if (Node == null)
+                    {
+                        break;
+                    }
+
+                    CacheBucket Bucket = Cache[Node.Value];
+
+                    int TimeDelta = RingDelta(Bucket.Timestamp, Timestamp);
+
+                    if ((uint)TimeDelta <= (uint)MaxTimeDelta)
+                    {
+                        break;
+                    }
+
+                    if (Cache.TryRemove(Node.Value, out Bucket))
+                    {
+                        TotalSize -= Bucket.Size;
+
+                        SortedCache.Remove(Bucket.Node);
+                    }
+                }
+            }
+        }
+
+        private static int RingDelta(int Old, int New)
+        {
+            if ((uint)New < (uint)Old)
+            {
+                return New + (~Old + 1);
+            }
+            else
+            {
+                return New - Old;
+            }
+        }
+    }
+}
+\ No newline at end of file