diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 306c368d..c7a8389d 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -154,6 +154,7 @@
+
diff --git a/ArcFormats/PackedStream.cs b/ArcFormats/PackedStream.cs
new file mode 100644
index 00000000..7286f499
--- /dev/null
+++ b/ArcFormats/PackedStream.cs
@@ -0,0 +1,147 @@
+//! \file PackedStream.cs
+//! \date 2017 Dec 31
+//! \brief Generic class representing compressed stream.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace GameRes.Compression
+{
+ public interface IStreamFilter : IDisposable
+ {
+ ///
+ /// Initialize filter on top of specified stream.
+ ///
+ void Initialize (Stream input);
+
+ ///
+ /// Whether filter has reached an end.
+ ///
+ bool Eof { get; }
+
+ ///
+ /// Continue data extraction from underlying stream.
+ ///
+ /// Returns number of bytes read.
+ int Continue (byte[] buffer, int pos, int count);
+ }
+
+ public abstract class Decompressor : IStreamFilter
+ {
+ IEnumerator m_unpack;
+ protected byte[] m_buffer;
+ protected int m_pos;
+ protected int m_length;
+
+ public abstract void Initialize (Stream input);
+
+ public bool Eof { get; private set; }
+
+ public int Continue (byte[] buffer, int pos, int count)
+ {
+ m_buffer = buffer;
+ m_pos = pos;
+ m_length = count;
+ if (null == m_unpack)
+ m_unpack = Unpack();
+ Eof = !m_unpack.MoveNext();
+ return m_pos - pos;
+ }
+
+ ///
+ /// Decompression coroutine that updates m_buffer with each MoveNext call.
+ ///
+ protected abstract IEnumerator Unpack ();
+
+ #region IDisposable Members
+ bool m_disposed = false;
+ public void Dispose ()
+ {
+ Dispose (true);
+ GC.SuppressFinalize (this);
+ }
+
+ protected virtual void Dispose (bool disposing)
+ {
+ if (!m_disposed)
+ {
+ if (m_unpack != null)
+ m_unpack.Dispose();
+ m_disposed = true;
+ }
+ }
+ #endregion
+ }
+
+ public class PackedStream : GameRes.Formats.InputProxyStream
+ where TDecompressor : IStreamFilter, new()
+ {
+ TDecompressor m_reader;
+
+ public PackedStream (Stream input, bool leave_open = false) : base (input, leave_open)
+ {
+ m_reader = new TDecompressor();
+ m_reader.Initialize (input);
+ }
+
+ public override bool CanSeek { get { return false; } }
+ public override long Length
+ {
+ get { throw new NotSupportedException ("Stream.Length property is not supported"); }
+ }
+ public override long Position
+ {
+ get { throw new NotSupportedException ("Stream.Position property is not supported"); }
+ set { throw new NotSupportedException ("Stream.Position property is not supported"); }
+ }
+
+ public override int Read (byte[] buffer, int offset, int count)
+ {
+ if (!m_reader.Eof && count > 0)
+ return m_reader.Continue (buffer, offset, count);
+ return 0;
+ }
+
+ public override void Flush()
+ {
+ }
+
+ public override long Seek (long offset, SeekOrigin origin)
+ {
+ throw new NotSupportedException ("Stream.Seek method is not supported");
+ }
+
+ #region IDisposable Members
+ bool m_disposed = false;
+ protected override void Dispose (bool disposing)
+ {
+ if (!m_disposed)
+ {
+ m_reader.Dispose();
+ m_disposed = true;
+ base.Dispose (disposing);
+ }
+ }
+ #endregion
+ }
+}