feat: Adds a memory mirrored ring buffer for networking. (#1533)

## Breaking Changes

Incoming packet registration signature has changed to:
```cs
delegate* void OnReceiveCallback(NetState state, SpanReader reader, int packetLength);

IncomingPackets.Register(int packetID, int length, bool ingame, OnReceiveCallback onReceive);
```

For example, an incoming packet handler signature would now look like this:
```cs
public static void SomeIncomingPacket(NetState state, SpanReader reader, int packetLength)
{
    // Parse the data
}
```

## Summary

Updates the network Pipe class to use a mirrored memory technique. This technique involves mapping the same physical memory to two contiguous virtual memory spaces so the byte buffer appears duplicated. This allows writing to a double-sized array to wrap around without the need for the `CircularBuffer` classes.

In practice this allows us to use `Span<byte>` as if the buffer was a regular array.


### Bug Fixes

- [X] Fixes bad fixed length string parsing

.github/workflows/build-test.yml

@@ -80,7 +80,7 @@ jobs:
       - name: Setup .NET 7
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: 7.0.400
+          dotnet-version: 7.0.401
       - name: Build
         run: ./publish.sh Release
       - name: Test

Projects/Server.Tests/Tests/Network/Packets/Outgoing/AccountPacketTests.cs

@@ -84,8 +84,8 @@ public void TestChangeCharacter()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendChangeCharacter(account);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -97,8 +97,8 @@ public void TestClientVersionReq()
 
         ns.SendClientVersionRequest();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -109,8 +109,8 @@ public void TestDeleteResult()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendCharacterDeleteResult(DeleteResultType.BadRequest);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -121,8 +121,8 @@ public void TestPopupMessage()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendPopupMessage(PMMessage.LoginSyncError);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Theory, InlineData(ProtocolChanges.Version70610), InlineData(ProtocolChanges.Version6000)]
@@ -148,8 +148,8 @@ public void TestSupportedFeatures(ProtocolChanges protocolChanges)
         var expected = new SupportedFeatures(ns).Compile();
         ns.SendSupportedFeature();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -169,8 +169,8 @@ public void TestLoginConfirm()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendLoginConfirmation(m);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -181,8 +181,8 @@ public void TestLoginComplete()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendLoginComplete();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -206,8 +206,8 @@ public void TestCharacterListUpdate()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendCharacterListUpdate(account);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -240,8 +240,8 @@ public void TestCharacterList70130()
 
         ns.SendCharacterList();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -273,8 +273,8 @@ public void TestCharacterListOld()
 
         ns.SendCharacterList();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -286,8 +286,8 @@ public void TestAccountLoginRej()
         var ns = PacketTestUtilities.CreateTestNetState();
         ns.SendAccountLoginRejected(reason);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -305,8 +305,8 @@ public void TestAccountLoginAck()
 
         ns.SendAccountLoginAck();
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 
     [Fact]
@@ -321,7 +321,7 @@ public void TestPlayServerAck()
 
         ns.SendPlayServerAck(si, authId);
 
-        var result = ns.SendPipe.Reader.TryRead();
-        AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+        var result = ns.SendPipe.Reader.AvailableToRead();
+        AssertThat.Equal(result, expected);
     }
 }

Projects/Server.Tests/Tests/Network/Packets/Outgoing/CombatPacketTests.cs

@@ -17,8 +17,8 @@ public void TestSwing()
             var ns = PacketTestUtilities.CreateTestNetState();
             ns.SendSwing(attacker, defender);
 
-            var result = ns.SendPipe.Reader.TryRead();
-            AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+            var result = ns.SendPipe.Reader.AvailableToRead();
+            AssertThat.Equal(result, expected);
         }
 
         [Theory, InlineData(true), InlineData(false)]
@@ -29,8 +29,8 @@ public void TestSetWarMode(bool warmode)
             var ns = PacketTestUtilities.CreateTestNetState();
             ns.SendSetWarMode(warmode);
 
-            var result = ns.SendPipe.Reader.TryRead();
-            AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+            var result = ns.SendPipe.Reader.AvailableToRead();
+            AssertThat.Equal(result, expected);
         }
 
         [Fact]
@@ -43,8 +43,8 @@ public void TestChangeCombatant()
             var ns = PacketTestUtilities.CreateTestNetState();
             ns.SendChangeCombatant(serial);
 
-            var result = ns.SendPipe.Reader.TryRead();
-            AssertThat.Equal(result.Buffer[0].AsSpan(0), expected);
+            var result = ns.SendPipe.Reader.AvailableToRead();
+            AssertThat.Equal(result, expected);
         }
     }
 }