Initial commit

src/MasterMemory/HeaderFormatterResolver.cs

@@ -0,0 +1,37 @@
+using MessagePack;
+using MessagePack.Formatters;
+
+namespace MariesWonderland.MasterMemory;
+
+/// <summary>
+/// MessagePack resolver used exclusively to deserialize the binary database header
+/// (<c>Dictionary&lt;string, (int, int)&gt;</c> mapping table names to data offsets).
+/// </summary>
+internal sealed class HeaderFormatterResolver : IFormatterResolver
+{
+    public static readonly IFormatterResolver Instance = new HeaderFormatterResolver();
+
+    /// <summary>Pre-configured options using this resolver (no compression for header).</summary>
+    public static readonly MessagePackSerializerOptions StandardOptions =
+        MessagePackSerializerOptions.Standard.WithResolver(Instance);
+
+    private HeaderFormatterResolver() { }
+
+    /// <inheritdoc/>
+    public IMessagePackFormatter<T>? GetFormatter<T>()
+    {
+        if (typeof(T) == typeof(Dictionary<string, (int, int)>))
+            return (IMessagePackFormatter<T>)(object)new DictionaryFormatter<string, (int, int)>();
+
+        if (typeof(T) == typeof(string))
+            return (IMessagePackFormatter<T>)(object)NullableStringFormatter.Instance;
+
+        if (typeof(T) == typeof((int, int)))
+            return (IMessagePackFormatter<T>)(object)new IntIntValueTupleFormatter();
+
+        if (typeof(T) == typeof(int))
+            return (IMessagePackFormatter<T>)(object)Int32Formatter.Instance;
+
+        return null;
+    }
+}