1 files changed, 51 insertions, 0 deletions
diff --git a/crypto/src/util/io/TeeInputStream.cs b/crypto/src/util/io/TeeInputStream.cs
new file mode 100644
index 000000000..373df4502
--- /dev/null
+++ b/crypto/src/util/io/TeeInputStream.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+
+namespace Org.BouncyCastle.Utilities.IO
+{
+	public class TeeInputStream
+		: BaseInputStream
+	{
+		private readonly Stream input, tee;
+
+		public TeeInputStream(Stream input, Stream tee)
+		{
+			Debug.Assert(input.CanRead);
+			Debug.Assert(tee.CanWrite);
+
+			this.input = input;
+			this.tee = tee;
+		}
+
+		public override void Close()
+		{
+			input.Close();
+			tee.Close();
+		}
+
+		public override int Read(byte[] buf, int off, int len)
+		{
+			int i = input.Read(buf, off, len);
+
+			if (i > 0)
+			{
+				tee.Write(buf, off, i);
+			}
+
+			return i;
+		}
+
+		public override int ReadByte()
+		{
+			int i = input.ReadByte();
+
+			if (i >= 0)
+			{
+				tee.WriteByte((byte)i);
+			}
+
+			return i;
+		}
+	}
+}