Add Z3DS metadata structures

SabreTools.Data.Models/N3DS/Enums.cs

@@ -226,4 +226,18 @@ namespace SabreTools.Data.Models.N3DS
         Optional = 0x4000,
         Shared = 0x8000,
     }
+
+    /// <see href="https://github.com/azahar-emu/azahar/blob/master/src/common/zstd_compression.h"/>
+    public enum Z3DSMetadataItemType : byte
+    {
+        /// <summary>
+        /// End marker
+        /// </summary>
+        End = 0,
+
+        /// <summary>
+        /// Binary metadata
+        /// </summary>
+        Binary = 1,
+    }
 }

SabreTools.Data.Models/N3DS/Z3DSMetadata.cs

@@ -0,0 +1,20 @@
+namespace SabreTools.Data.Models.N3DS
+{
+    /// <summary>
+    /// Metadata block whose size is defined by <see cref="Z3DSFileHeader.MetadataSize"/>
+    /// </summary>
+    /// <see href="https://github.com/azahar-emu/azahar/blob/master/src/common/zstd_compression.h"/>
+    public class Z3DSMetadata
+    {
+        /// <summary>
+        /// Metadata version
+        /// </summary>
+        /// <remarks>Currently only a value of 1 is expected</remarks>
+        public byte Version { get; set; }
+
+        /// <summary>
+        /// Set of metadata entries in the block
+        /// </summary>
+        public Z3DSMetadataItem[] Items { get; set; } = [];
+    }
+}

SabreTools.Data.Models/N3DS/Z3DSMetadataItem.cs

@@ -0,0 +1,38 @@
+namespace SabreTools.Data.Models.N3DS
+{
+    /// <summary>
+    /// Metadata item entry
+    /// </summary>
+    /// <see href="https://github.com/azahar-emu/azahar/blob/master/src/common/zstd_compression.h"/>
+    public class Z3DSMetadataItem
+    {
+        /// <summary>
+        /// Item type
+        /// </summary>
+        public Z3DSMetadataItemType Type { get; set; }
+
+        /// <summary>
+        /// Length of the name field
+        /// </summary>
+        public byte NameLength { get; set; }
+
+        /// <summary>
+        /// Length of the data field
+        /// </summary>
+        public ushort DataLength { get; set; }
+
+        /// <summary>
+        /// Name encoded as bytes whose length is given
+        /// by <see cref="NameLength"/>
+        /// </summary>
+        /// <remarks>Ignored if <see cref="Type"/> is End</remarks>
+        public byte[] Name { get; set; } = [];
+
+        /// <summary>
+        /// Data encoded as bytes whose length is given
+        /// by <see cref="DataLength"/>
+        /// </summary>
+        /// <remarks>Ignored if <see cref="Type"/> is End</remarks>
+        public byte[] Data { get; set; } = [];
+    }
+}