From a359686171630c8efe9d64c13a8ce99a8e778ef3 Mon Sep 17 00:00:00 2001
From: wreng <mr-wrench@yandex.ru>
Date: Fri, 16 Feb 2024 20:13:10 +0300
Subject: [PATCH] Replaced list with cyclic buffer

---
 src/DotRecast.Core/Buffers/RcCyclicBuffer.cs  | 48 +++++++++++++++++++
 .../DtCrowdTelemetry.cs                       | 19 +++++---
 2 files changed, 61 insertions(+), 6 deletions(-)
 create mode 100644 src/DotRecast.Core/Buffers/RcCyclicBuffer.cs

diff --git a/src/DotRecast.Core/Buffers/RcCyclicBuffer.cs b/src/DotRecast.Core/Buffers/RcCyclicBuffer.cs
new file mode 100644
index 0000000..0dc6ffd
--- /dev/null
+++ b/src/DotRecast.Core/Buffers/RcCyclicBuffer.cs
@@ -0,0 +1,48 @@
+using System;
+
+namespace DotRecast.Core.Buffers
+{
+    public class RcCyclicBuffer<T>
+    {
+        public int MinIndex { get; private set; }
+        public int MaxIndex { get; private set; }
+        public int Count => MaxIndex - MinIndex + 1;
+        public readonly int Size;
+        
+        public T this[int index] => Get(index);
+
+        private readonly T[] _buffer;
+
+        public RcCyclicBuffer(in int size)
+        {
+            _buffer = new T[size];
+            Size = size;
+            MinIndex = 0;
+            MaxIndex = -1;
+        }
+
+        public void Add(in T item)
+        {
+            MaxIndex++;
+            var index = MaxIndex % Size;
+
+            if (MaxIndex >= Size)
+                MinIndex = MaxIndex - Size + 1;
+
+            _buffer[index] = item;
+        }
+
+        public T Get(in int index)
+        {
+            if (index < MinIndex || index > MaxIndex)
+                throw new ArgumentOutOfRangeException();
+
+            return _buffer[index % Size];
+        }
+
+        public Span<T> AsSpan()
+        {
+            return _buffer.AsSpan(0, Count);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/DotRecast.Detour.Crowd/DtCrowdTelemetry.cs b/src/DotRecast.Detour.Crowd/DtCrowdTelemetry.cs
index aadfb79..dbc3086 100644
--- a/src/DotRecast.Detour.Crowd/DtCrowdTelemetry.cs
+++ b/src/DotRecast.Detour.Crowd/DtCrowdTelemetry.cs
@@ -23,6 +23,7 @@ using System.Diagnostics;
 using System.Linq;
 using System.Reflection.Emit;
 using DotRecast.Core;
+using DotRecast.Core.Buffers;
 using DotRecast.Core.Numerics;
 
 namespace DotRecast.Detour.Crowd
@@ -34,7 +35,7 @@ namespace DotRecast.Detour.Crowd
         private float _maxTimeToFindPath;
 
         private readonly Dictionary<DtCrowdTimerLabel, long> _executionTimings = new Dictionary<DtCrowdTimerLabel, long>();
-        private readonly Dictionary<DtCrowdTimerLabel, List<long>> _executionTimingSamples = new Dictionary<DtCrowdTimerLabel, List<long>>();
+        private readonly Dictionary<DtCrowdTimerLabel, RcCyclicBuffer<long>> _executionTimingSamples = new Dictionary<DtCrowdTimerLabel, RcCyclicBuffer<long>>();
 
         public float MaxTimeToEnqueueRequest()
         {
@@ -87,17 +88,23 @@ namespace DotRecast.Detour.Crowd
             long duration = RcFrequency.Ticks - _executionTimings[name];
             if (!_executionTimingSamples.TryGetValue(name, out var s))
             {
-                s = new List<long>();
+                s = new RcCyclicBuffer<long>(TIMING_SAMPLES);
                 _executionTimingSamples.Add(name, s);
             }
 
-            if (s.Count == TIMING_SAMPLES)
+            s.Add(duration);
+            _executionTimings[name] = CalculateAverage(s.AsSpan());
+        }
+
+        private static long CalculateAverage(Span<long> buffer)
+        {
+            long sum = 0L;
+            foreach (var item in buffer)
             {
-                s.RemoveAt(0);
+                sum += item;
             }
 
-            s.Add(duration);
-            _executionTimings[name] = (long)s.Average();
+            return sum / buffer.Length;
         }
     }
 }
\ No newline at end of file