Init enter game

KcpSharp/Base/KcpPacketHeader.cs

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+using System.Buffers.Binary;
+using System.Diagnostics;
+
+namespace KianaBH.KcpSharp.Base;
+
+internal readonly struct KcpPacketHeader : IEquatable<KcpPacketHeader>
+{
+    public KcpPacketHeader(KcpCommand command, byte fragment, ushort windowSize, uint timestamp, uint serialNumber,
+        uint unacknowledged)
+    {
+        Command = command;
+        Fragment = fragment;
+        WindowSize = windowSize;
+        Timestamp = timestamp;
+        SerialNumber = serialNumber;
+        Unacknowledged = unacknowledged;
+    }
+
+    internal KcpPacketHeader(byte fragment)
+    {
+        Command = 0;
+        Fragment = fragment;
+        WindowSize = 0;
+        Timestamp = 0;
+        SerialNumber = 0;
+        Unacknowledged = 0;
+    }
+
+    public KcpCommand Command { get; }
+    public byte Fragment { get; }
+    public ushort WindowSize { get; }
+    public uint Timestamp { get; }
+    public uint SerialNumber { get; }
+    public uint Unacknowledged { get; }
+
+    public bool Equals(KcpPacketHeader other)
+    {
+        return Command == other.Command && Fragment == other.Fragment && WindowSize == other.WindowSize &&
+               Timestamp == other.Timestamp && SerialNumber == other.SerialNumber &&
+               Unacknowledged == other.Unacknowledged;
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is KcpPacketHeader other && Equals(other);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(Command, Fragment, WindowSize, Timestamp, SerialNumber, Unacknowledged);
+    }
+
+    public static KcpPacketHeader Parse(ReadOnlySpan<byte> buffer)
+    {
+        Debug.Assert(buffer.Length >= 16);
+        return new KcpPacketHeader(
+            (KcpCommand)buffer[0],
+            buffer[1],
+            BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(2)),
+            BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(4)),
+            BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(8)),
+            BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(12))
+        );
+    }
+
+    internal void EncodeHeader(ulong? conversationId, int payloadLength, Span<byte> destination, out int bytesWritten)
+    {
+        Debug.Assert(destination.Length >= 20);
+        if (conversationId.HasValue)
+        {
+            BinaryPrimitives.WriteUInt64BigEndian(destination, conversationId.GetValueOrDefault());
+            destination = destination.Slice(8);
+            bytesWritten = 28;
+        }
+        else
+        {
+            bytesWritten = 20;
+        }
+
+        Debug.Assert(destination.Length >= 20);
+        destination[1] = Fragment;
+        destination[0] = (byte)Command;
+        BinaryPrimitives.WriteUInt16LittleEndian(destination.Slice(2), WindowSize);
+        BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(4), Timestamp);
+        BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(8), SerialNumber);
+        BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(12), Unacknowledged);
+        BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(16), (uint)payloadLength);
+    }
+}