1 files changed, 101 insertions, 0 deletions
diff --git a/SevenZip/ArchiveEmulationStreamProxy.cs b/SevenZip/ArchiveEmulationStreamProxy.cs
new file mode 100644
index 00000000..c0bdaed2
--- /dev/null
+++ b/SevenZip/ArchiveEmulationStreamProxy.cs
@@ -0,0 +1,101 @@
+using System.IO;
+using System;
+
+namespace SevenZip
+{    
+    /// <summary>
+    /// The Stream extension class to emulate the archive part of a stream.
+    /// </summary>
+    internal class ArchiveEmulationStreamProxy : Stream, IDisposable
+    {
+        /// <summary>
+        /// Gets the file offset.
+        /// </summary>
+        public int Offset { get; private set; }
+
+        /// <summary>
+        /// The source wrapped stream.
+        /// </summary>
+        public Stream Source { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the ArchiveEmulationStream class.
+        /// </summary>
+        /// <param name="stream">The stream to wrap.</param>
+        /// <param name="offset">The stream offset.</param>
+        public ArchiveEmulationStreamProxy(Stream stream, int offset)
+        {
+            Source = stream;
+            Offset = offset;
+            Source.Position = offset;
+        }
+
+        public override bool CanRead
+        {
+            get { return Source.CanRead; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return Source.CanSeek; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return Source.CanWrite; }
+        }
+
+        public override void Flush()
+        {
+            Source.Flush();
+        }
+
+        public override long Length
+        {
+            get { return Source.Length - Offset; }
+        }
+
+        public override long Position
+        {
+            get
+            {
+                return Source.Position - Offset;
+            }
+            set
+            {
+                Source.Position = value;
+            }
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            return Source.Read(buffer, offset, count);
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            return Source.Seek(origin == SeekOrigin.Begin ? offset + Offset : offset,
+                origin) - Offset;
+        }
+
+        public override void SetLength(long value)
+        {
+            Source.SetLength(value);
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            Source.Write(buffer, offset, count);
+        }
+
+        public new void Dispose()
+        {
+            Source.Dispose();
+        }
+
+        public override void Close()
+        {
+            Source.Close();
+        }
+    }
+}