Extract out FileTypes namespace

SabreTools.FileTypes/Aaru/IndexHeader.cs

@@ -0,0 +1,40 @@
+using System.IO;
+using System.Text;
+
+using SabreTools.Core;
+
+namespace SabreTools.FileTypes.Aaru
+{
+    /// <summary>
+    /// Header for the index, followed by entries
+    /// </summary>
+    /// <see cref="https://github.com/aaru-dps/Aaru/blob/master/Aaru.Images/AaruFormat/Structs.cs" />
+    public class IndexHeader
+    {
+        /// <summary>Identifier, <see cref="BlockType.Index" /></summary>
+        public AaruBlockType identifier;
+        /// <summary>How many entries follow this header</summary>
+        public ushort entries;
+        /// <summary>CRC64-ECMA of the index</summary>
+        public ulong crc64;
+
+        /// <summary>
+        /// Read a stream as an IndexHeader
+        /// </summary>
+        /// <param name="stream">IndexHeader as a stream</param>
+        /// <returns>Populated IndexHeader, null on failure</returns>
+        public static IndexHeader Deserialize(Stream stream)
+        {
+            IndexHeader indexHeader = new IndexHeader();
+
+            using (BinaryReader br = new BinaryReader(stream, Encoding.Default, true))
+            {
+                indexHeader.identifier = (AaruBlockType)br.ReadUInt32();
+                indexHeader.entries = br.ReadUInt16();
+                indexHeader.crc64 = br.ReadUInt64();
+            }
+
+            return indexHeader;
+        }
+    }
+}