Add CircularBuffer data structure (#115)

Author: lucasteles

benchmarks/Backdash.Benchmarks.Ping/PingMessageHandler.cs

@@ -1,5 +1,5 @@
-using System.Diagnostics;
 using System.Net;
+using Backdash.Core;
 using Backdash.Network.Client;
 
 namespace Backdash.Benchmarks.Ping;
@@ -24,6 +24,6 @@ int bytesReceived
             _ => throw new ArgumentOutOfRangeException(nameof(message), message, null),
         };
 
-        Trace.Assert(sender.TrySendTo(from, reply));
+        ThrowIf.Assert(sender.TrySendTo(from, reply));
     }
 }

benchmarks/Backdash.Benchmarks/Cases/UdpClientBenchmark.cs

@@ -1,6 +1,6 @@
-using System.Diagnostics;
 using System.Net;
 using Backdash.Benchmarks.Network;
+using Backdash.Core;
 
 #pragma warning disable CS0649, AsyncFixer01, AsyncFixer02
 // ReSharper disable AccessToDisposedClosure
@@ -44,17 +44,17 @@ void OnProcessed(long count)
         IPEndPoint pongerEndpoint = new(IPAddress.Loopback, 9001);
         var pongerAddress = pongerEndpoint.Serialize();
 
-        Trace.Assert(pinger.TrySendTo(pongerAddress, PingMessage.Ping));
+        ThrowIf.Assert(pinger.TrySendTo(pongerAddress, PingMessage.Ping));
 
         await Task.WhenAll(
             pinger.Start(ct),
             ponger.Start(ct)
         ).ConfigureAwait(false);
 
         pingerHandler.OnProcessed -= OnProcessed;
-        Trace.Assert(pingerHandler.BadMessages is 0,
+        ThrowIf.Assert(pingerHandler.BadMessages is 0,
             $"** Pinger: {pingerHandler.BadMessages} bad messages");
-        Trace.Assert(pingerHandler.ProcessedCount >= numberOfSpins,
+        ThrowIf.Assert(pingerHandler.ProcessedCount >= numberOfSpins,
             $"** Pinger incomplete (Expected: >= {numberOfSpins}, Received: {pingerHandler.ProcessedCount})");
     }
 }

benchmarks/Backdash.Benchmarks/Network/Message.cs

@@ -1,5 +1,5 @@
-using System.Diagnostics;
 using System.Net;
+using Backdash.Core;
 using Backdash.Network.Client;
 
 #pragma warning disable CS9113 // Parameter is unread.
@@ -34,7 +34,7 @@ public void OnPeerMessage(in PingMessage message, SocketAddress from, int bytesR
             _ => throw new ArgumentOutOfRangeException(nameof(message), message, null),
         };
 
-        Trace.Assert(sender.TrySendTo(from, reply));
+        ThrowIf.Assert(sender.TrySendTo(from, reply));
         OnProcessed(processedCount);
 #if DEBUG
         Console.WriteLine(

src/Backdash/Backends/BackendServices.cs

@@ -26,6 +26,8 @@ sealed class BackendServices<TInput> where TInput : unmanaged
     public IDelayStrategy DelayStrategy { get; }
     public IInputListener<TInput>? InputListener { get; }
 
+    public EqualityComparer<TInput> InputComparer { get; }
+
     public BackendServices(NetcodeOptions options, SessionServices<TInput>? services)
     {
         ChecksumProvider = services?.ChecksumProvider ?? new Fletcher32ChecksumProvider();
@@ -35,6 +37,7 @@ public BackendServices(NetcodeOptions options, SessionServices<TInput>? services
         Random = new DefaultRandomNumberGenerator(services?.Random ?? System.Random.Shared);
         DelayStrategy = DelayStrategyFactory.Create(Random, options.Protocol.DelayStrategy);
         InputGenerator = services?.InputGenerator;
+        InputComparer = services?.InputComparer ?? EqualityComparer<TInput>.Default;
 
         InputSerializer = services?.InputSerializer ?? BinarySerializerFactory
             .FindOrThrow<TInput>(options.UseNetworkEndianness);

src/Backdash/Backends/LocalBackend.cs

@@ -37,7 +37,8 @@ public LocalBackend(NetcodeOptions options, BackendServices<TInput> services)
             addedPlayers,
             services.StateStore,
             services.ChecksumProvider,
-            new(Max.NumberOfPlayers)
+            new(Max.NumberOfPlayers),
+            services.InputComparer
         )
         {
             Callbacks = callbacks,
@@ -177,7 +178,7 @@ public void AdvanceFrame()
 
     public void SetFrameDelay(PlayerHandle player, int delayInFrames)
     {
-        ThrowHelpers.ThrowIfArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
+        ThrowIf.ArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
         ArgumentOutOfRangeException.ThrowIfNegative(delayInFrames);
         synchronizer.SetFrameDelay(player, delayInFrames);
     }

src/Backdash/Backends/RemoteBackend.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using Backdash.Core;
@@ -36,6 +35,8 @@ sealed class RemoteBackend<TInput> : INetcodeSession<TInput>, IProtocolNetworkEv
     readonly HashSet<PlayerHandle> addedSpectators = [];
     readonly IInputListener<TInput>? inputListener;
     public IDeterministicRandom Random { get; }
+    readonly EqualityComparer<TInput> inputComparer;
+    readonly EqualityComparer<ConfirmedInputs<TInput>> inputGroupComparer;
 
     bool isSynchronizing = true;
     int nextRecommendedInterval;
@@ -59,7 +60,7 @@ BackendServices<TInput> services
         ArgumentNullException.ThrowIfNull(options);
         ArgumentOutOfRangeException.ThrowIfNegativeOrZero(port);
         ArgumentOutOfRangeException.ThrowIfNegativeOrZero(options.FramesPerSecond);
-        ThrowHelpers.ThrowIfArgumentOutOfBounds(options.SpectatorOffset, min: Max.NumberOfPlayers);
+        ThrowIf.ArgumentOutOfBounds(options.SpectatorOffset, min: Max.NumberOfPlayers);
 
         this.options = options;
         inputSerializer = services.InputSerializer;
@@ -68,6 +69,8 @@ BackendServices<TInput> services
         inputListener = services.InputListener;
         Random = services.DeterministicRandom;
         syncNumber = services.Random.MagicNumber();
+        inputComparer = services.InputComparer;
+        inputGroupComparer = ConfirmedInputComparer<TInput>.Create(services.InputComparer);
 
         peerInputEventQueue = new();
         peerCombinedInputsEventPublisher = new ProtocolCombinedInputsEventPublisher<TInput>(peerInputEventQueue);
@@ -84,7 +87,8 @@ BackendServices<TInput> services
             addedPlayers,
             services.StateStore,
             services.ChecksumProvider,
-            localConnections
+            localConnections,
+            inputComparer
         )
         {
             Callbacks = callbacks,
@@ -253,7 +257,7 @@ public void SetHandler(INetcodeSessionHandler handler)
 
     public void SetFrameDelay(PlayerHandle player, int delayInFrames)
     {
-        ThrowHelpers.ThrowIfArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
+        ThrowIf.ArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
         ArgumentOutOfRangeException.ThrowIfNegative(delayInFrames);
         synchronizer.SetFrameDelay(player, delayInFrames);
     }
@@ -295,7 +299,7 @@ ResultCode AddRemotePlayer(RemotePlayer player)
         var endpoint = player.EndPoint;
         var protocol = peerConnectionFactory.Create(
             new(player.Handle, endpoint, localConnections, syncNumber),
-            inputSerializer, peerInputEventQueue
+            inputSerializer, peerInputEventQueue, inputComparer
         );
 
         peerObservers.Add(protocol.GetUdpObserver());
@@ -334,7 +338,8 @@ ResultCode AddSpectator(Spectator spectator)
         var protocol = peerConnectionFactory.Create(
             new(spectatorHandle, spectator.EndPoint, localConnections, syncNumber),
             inputGroupSerializer,
-            peerCombinedInputsEventPublisher
+            peerCombinedInputsEventPublisher,
+            inputGroupComparer
         );
         peerObservers.Add(protocol.GetUdpObserver());
         spectators.Add(protocol);
@@ -432,7 +437,7 @@ void ConsumeProtocolInputEvents()
             var currentRemoteFrame = localConnections[player].LastFrame;
             var newRemoteFrame = eventInput.Frame;
 
-            Trace.Assert(currentRemoteFrame.IsNull || newRemoteFrame == currentRemoteFrame.Next());
+            ThrowIf.Assert(currentRemoteFrame.IsNull || newRemoteFrame == currentRemoteFrame.Next());
             synchronizer.AddRemoteInput(in player, eventInput);
             // Notify the other endpoints which frame we received from a peer
             logger.Write(LogLevel.Trace, $"setting remote connect status frame {player} to {eventInput.Frame}");
@@ -490,7 +495,7 @@ void DoSync()
             eps[i]?.SetLocalFrameNumber(currentFrame, options.FramesPerSecond);
 
         var minConfirmedFrame = NumberOfPlayers <= 2 ? MinimumFrame2Players() : MinimumFrameNPlayers();
-        Trace.Assert(minConfirmedFrame != Frame.MaxValue);
+        ThrowIf.Assert(minConfirmedFrame != Frame.MaxValue);
         logger.Write(LogLevel.Trace, $"last confirmed frame in p2p backend is {minConfirmedFrame}");
 
         if (minConfirmedFrame >= Frame.Zero)
@@ -697,7 +702,7 @@ void DisconnectPlayerQueue(in PlayerHandle player, in Frame syncTo)
             $"Changing player {player} local connect status for last frame from {connStatus.LastFrame} to {syncTo} on disconnect request (current: {frameCount})");
         connStatus.Disconnected = true;
         connStatus.LastFrame = syncTo;
-        if (syncTo < frameCount && syncTo.IsNotNull)
+        if (syncTo < frameCount && !syncTo.IsNull)
         {
             logger.Write(LogLevel.Information,
                 $"adjusting simulation to account for the fact that {player} disconnected on frame {syncTo}");

src/Backdash/Backends/ReplayBackend.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using Backdash.Core;
 using Backdash.Data;
 using Backdash.Network;
@@ -140,7 +139,7 @@ public ResultCode SynchronizeInputs()
         if (confirmed.Count is 0 && CurrentFrame == Frame.Zero)
             return ResultCode.NotSynchronized;
 
-        Trace.Assert(confirmed.Count > 0);
+        ThrowIf.Assert(confirmed.Count > 0);
         NumberOfPlayers = confirmed.Count;
 
         if (syncInputBuffer.Length != NumberOfPlayers)
@@ -185,7 +184,7 @@ public void LoadFrame(in Frame frame)
 
         try
         {
-            var savedFrame = stateStore.Load(frame);
+            var savedFrame = stateStore.Load(in frame);
             logger.Write(LogLevel.Trace,
                 $"Loading replay frame {savedFrame.Frame} (checksum: {savedFrame.Checksum})");
             var offset = 0;

src/Backdash/Backends/SpectatorBackend.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Net;
 using Backdash.Core;
 using Backdash.Data;
@@ -78,7 +77,8 @@ public SpectatorBackend(int port,
         ProtocolState protocolState =
             new(new(PlayerType.Remote, 0), hostEndpoint, localConnections, magicNumber);
 
-        host = peerConnectionFactory.Create(protocolState, inputGroupSerializer, this);
+        var inputGroupComparer = ConfirmedInputComparer<TInput>.Create(services.InputComparer);
+        host = peerConnectionFactory.Create(protocolState, inputGroupSerializer, this, inputGroupComparer);
         peerObservers.Add(host.GetUdpObserver());
         host.Synchronize();
         isSynchronizing = true;
@@ -227,7 +227,7 @@ public ResultCode SynchronizeInputs()
             return ResultCode.InputDropped;
         }
 
-        Trace.Assert(input.Data.Count > 0);
+        ThrowIf.Assert(input.Data.Count > 0);
         NumberOfPlayers = input.Data.Count;
 
         if (syncInputBuffer.Length != NumberOfPlayers)

src/Backdash/Backends/SyncTestBackend.cs

@@ -64,7 +64,8 @@ public SyncTestBackend(NetcodeOptions options,
             addedPlayers,
             services.StateStore,
             services.ChecksumProvider,
-            new(Max.NumberOfPlayers)
+            new(Max.NumberOfPlayers),
+            services.InputComparer
         )
         {
             Callbacks = callbacks,
@@ -299,7 +300,7 @@ void LogText(LogLevel level, string text)
 
     public void SetFrameDelay(PlayerHandle player, int delayInFrames)
     {
-        ThrowHelpers.ThrowIfArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
+        ThrowIf.ArgumentOutOfBounds(player.InternalQueue, 0, addedPlayers.Count);
         ArgumentOutOfRangeException.ThrowIfNegative(delayInFrames);
         synchronizer.SetFrameDelay(player, delayInFrames);
     }

src/Backdash/Core/Default.cs

@@ -41,11 +41,11 @@ static class Default
     ///<value>Defaults to <c>32_768</c></value>
     public const int MaxSeqDistance = 1 << 15;
 
-    ///<value>Defaults to <c>500</c> milliseconds</value>
-    public const int ConsistencyCheckInterval = 500;
+    ///<value>Defaults to <c>3_000</c> milliseconds</value>
+    public const int ConsistencyCheckInterval = 3_000;
 
-    ///<value>Defaults to <c>6_000</c> milliseconds</value>
-    public const int ConsistencyCheckTimeout = 6_000;
+    ///<value>Defaults to <c>10_000</c> milliseconds</value>
+    public const int ConsistencyCheckTimeout = 10_000;
 
     ///<value>Defaults to <c>8</c></value>
     public const int ConsistencyCheckOffset = 8;