Initial commit

src/MasterMemory/IntIntValueTupleFormatter.cs

@@ -0,0 +1,30 @@
+using MessagePack;
+using MessagePack.Formatters;
+
+namespace MariesWonderland.MasterMemory;
+
+/// <summary>
+/// MessagePack formatter for <c>(int, int)</c> value tuples stored as 2-element arrays
+/// in the master database binary header.
+/// </summary>
+internal sealed class IntIntValueTupleFormatter : IMessagePackFormatter<(int, int)>
+{
+    public void Serialize(ref MessagePackWriter writer, (int, int) value, MessagePackSerializerOptions options)
+    {
+        writer.WriteArrayHeader(2);
+        writer.WriteInt32(value.Item1);
+        writer.WriteInt32(value.Item2);
+    }
+
+    public (int, int) Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options)
+    {
+        if (reader.IsNil)
+            throw new InvalidOperationException("Header tuple entry is nil.");
+
+        var count = reader.ReadArrayHeader();
+        if (count != 2)
+            throw new InvalidOperationException($"Expected 2-element tuple, got {count}.");
+
+        return (reader.ReadInt32(), reader.ReadInt32());
+    }
+}