DigestStream.cs :  » PDF » iTextSharp » Org » BouncyCastle » Crypto » IO » C# / CSharp Open Source

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; }
    }

    public override void Close()
    {
      stream.Close();
    }

    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);
    }
  }
}