ChocolArm64/ATranslatorCache.cs

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C#
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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Threading;
namespace ChocolArm64
{
class ATranslatorCache
{
//Maximum size of the cache, in bytes, measured in ARM code size.
private const int MaxTotalSize = 4 * 1024 * 256;
//Minimum time required in milliseconds for a method to be eligible for deletion.
private const int MinTimeDelta = 2 * 60000;
//Minimum number of calls required to update the timestamp.
private const int MinCallCountForUpdate = 250;
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 long 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 = GetTimestamp();
}
}
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()
{
long Timestamp = GetTimestamp();
while (TotalSize > MaxTotalSize)
{
lock (SortedCache)
{
LinkedListNode<long> Node = SortedCache.First;
if (Node == null)
{
break;
}
CacheBucket Bucket = Cache[Node.Value];
long TimeDelta = Bucket.Timestamp - Timestamp;
if (TimeDelta <= MinTimeDelta)
{
break;
}
if (Cache.TryRemove(Node.Value, out Bucket))
{
TotalSize -= Bucket.Size;
SortedCache.Remove(Bucket.Node);
}
}
}
}
private static long GetTimestamp()
{
long timestamp = Stopwatch.GetTimestamp();
return timestamp / (Stopwatch.Frequency / 1000);
}
}
}