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);
+ }
+ }
+}
+
|
