OG Xbox FATX fixes

AlignedStream.cs

@@ -25,7 +25,7 @@ public AlignedStream(Stream stream, int alignment)
         public override bool CanSeek { get { return true; } }
 
         byte[] AlignmentBuffer;
-        long AlignmentPosition = 0;
+        long AlignmentPosition = -1;
         private long position;
         bool FillBuffer = false;
 

DeviceStream.cs

@@ -0,0 +1,76 @@
+using System;
+using System.IO;
+
+using Fsp;
+
+namespace XboxWinFsp
+{
+	public class DeviceStream : Stream
+	{
+		AlignedStream AlignedStream;
+        long DriveSize;
+
+		public DeviceStream(String inputPath)
+		{
+            var sfh = Natives.CreateFile(inputPath,
+                EFileAccess.GenericRead | EFileAccess.GenericAll,
+                EFileShare.Read | EFileShare.Write,
+                IntPtr.Zero, ECreationDisposition.OpenExisting,
+                EFileAttributes.Normal, IntPtr.Zero);
+
+            if (sfh.IsInvalid)
+            {
+                throw new IOException("Cannot open device.");
+            }
+
+            // Get our device size
+            uint high = 0;
+            uint low = Natives.GetFileSize(sfh, ref high);
+            DriveSize = (high << 32) | low;
+
+            if (DriveSize == 0xffffffff)
+                DriveSize = Natives.GetDriveSize(sfh);
+
+            // Create a stream to read with
+            var stream = new FileStream(sfh, FileAccess.ReadWrite, 0x200 * 0x200, false);
+            AlignedStream = new AlignedStream(stream, 0x200 * 0x200);
+        }
+
+        public override bool CanRead => AlignedStream.CanRead;
+
+        public override bool CanSeek => AlignedStream.CanSeek;
+
+        public override bool CanWrite => AlignedStream.CanWrite;
+
+        public override long Length => DriveSize;
+
+        public override long Position { get => AlignedStream.Position; set => AlignedStream.Position = value; }
+
+        public override void Flush()
+        {
+            AlignedStream.Flush();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            return AlignedStream.Read(buffer, offset, count);
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            return AlignedStream.Seek(offset, origin);
+        }
+
+        public override void SetLength(long value)
+        {
+            DriveSize = (value >= 0) ? value : 0;
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            AlignedStream.Write(buffer, offset, count);
+        }
+    }
+}
+
+