If specified size is 0, calculate length.

DiscImageChef.Filters/ForcedSeekStream.cs

@@ -60,6 +60,8 @@ namespace DiscImageChef.Filters
             baseStream = (T)Activator.CreateInstance(typeof(T), parameters);
             backFile = Path.GetTempFileName();
             backStream = new FileStream(backFile, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
+            if(length == 0)
+                CalculateLength();
         }
 
         /// <summary>

DiscImageChef.Filters/XZ.cs

@@ -0,0 +1,41 @@
+// /***************************************************************************
+// The Disc Image Chef
+// ----------------------------------------------------------------------------
+//
+// Filename       : XZ.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : Component
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Description
+//
+// --[ License ] --------------------------------------------------------------
+//
+//     This library is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as
+//     published by the Free Software Foundation; either version 2.1 of the
+//     License, or (at your option) any later version.
+//
+//     This library is distributed in the hope that it will be useful, but
+//     WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+//     Lesser General Public License for more details.
+//
+//     You should have received a copy of the GNU Lesser General Public
+//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+// Copyright © 2011-2017 Natalia Portillo
+// ****************************************************************************/
+using System;
+namespace DiscImageChef.Filters
+{
+    public class XZ
+    {
+        public XZ()
+        {
+        }
+    }
+}