1 files changed, 140 insertions, 0 deletions
diff --git a/Crypto/src/crypto/io/DigestStream.cs b/Crypto/src/crypto/io/DigestStream.cs
new file mode 100644
index 000000000..a5b31f95c
--- /dev/null
+++ b/Crypto/src/crypto/io/DigestStream.cs
@@ -0,0 +1,140 @@
+using System;
+using System.IO;
+
+namespace Org.BouncyCastle.Crypto.IO
+{
+	public class DigestStream
+		: Stream
+	{
+		protected readonly Stream stream;
+		protected readonly IDigest inDigest;
+		protected readonly IDigest outDigest;
+
+		public DigestStream(
+			Stream	stream,
+			IDigest	readDigest,
+			IDigest	writeDigest)
+		{
+			this.stream = stream;
+			this.inDigest = readDigest;
+			this.outDigest = writeDigest;
+		}
+
+		public virtual IDigest ReadDigest()
+		{
+			return inDigest;
+		}
+
+		public virtual IDigest WriteDigest()
+		{
+			return outDigest;
+		}
+
+		public override int Read(
+			byte[]	buffer,
+			int		offset,
+			int		count)
+		{
+			int n = stream.Read(buffer, offset, count);
+			if (inDigest != null)
+			{
+				if (n > 0)
+				{
+					inDigest.BlockUpdate(buffer, offset, n);
+				}
+			}
+			return n;
+		}
+
+		public override int ReadByte()
+		{
+			int b = stream.ReadByte();
+			if (inDigest != null)
+			{
+				if (b >= 0)
+				{
+					inDigest.Update((byte)b);
+				}
+			}
+			return b;
+		}
+
+		public override void Write(
+			byte[]	buffer,
+			int		offset,
+			int		count)
+		{
+			if (outDigest != null)
+			{
+				if (count > 0)
+				{
+					outDigest.BlockUpdate(buffer, offset, count);
+				}
+			}
+			stream.Write(buffer, offset, count);
+		}
+
+		public override void WriteByte(
+			byte b)
+		{
+			if (outDigest != null)
+			{
+				outDigest.Update(b);
+			}
+			stream.WriteByte(b);
+		}
+
+		public override bool CanRead
+		{
+			get { return stream.CanRead; }
+		}
+
+		public override bool CanWrite
+		{
+			get { return stream.CanWrite; }
+		}
+
+		public override bool CanSeek
+		{
+			get { return stream.CanSeek; }
+		}
+
+		public override long Length
+		{
+			get { return stream.Length; }
+		}
+
+		public override long Position
+		{
+			get { return stream.Position; }
+			set { stream.Position = value; }
+		}
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                stream.Dispose();
+            }
+        }
+
+		public override  void Flush()
+		{
+			stream.Flush();
+		}
+
+		public override long Seek(
+			long		offset,
+			SeekOrigin	origin)
+		{
+			return stream.Seek(offset, origin);
+		}
+
+		public override void SetLength(
+			long length)
+		{
+			stream.SetLength(length);
+		}
+	}
+}
+