BEROctetStringGenerator.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » C# / CSharp Open Source

using System;
using System.IO;

using Org.BouncyCastle.Utilities.IO;

namespace Org.BouncyCastle.Asn1{
  public class BerOctetStringGenerator
    : BerGenerator
  {
    public BerOctetStringGenerator(Stream outStream)
      : base(outStream)
    {
      WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.OctetString);
    }

    public BerOctetStringGenerator(
      Stream  outStream,
      int    tagNo,
      bool  isExplicit)
      : base(outStream, tagNo, isExplicit)
    {
      WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.OctetString);
    }

    public Stream GetOctetOutputStream()
    {
      return GetOctetOutputStream(new byte[1000]); // limit for CER encoding.
    }

    public Stream GetOctetOutputStream(
      int bufSize)
    {
      return bufSize < 1
        ?  GetOctetOutputStream()
        :  GetOctetOutputStream(new byte[bufSize]);
    }

    public Stream GetOctetOutputStream(
      byte[] buf)
    {
      return new BufferedBerOctetStream(this, buf);
    }

    private class BufferedBerOctetStream
      : BaseOutputStream
    {
      private byte[] _buf;
      private int    _off;
      private readonly BerOctetStringGenerator _gen;
      private readonly DerOutputStream _derOut;

      internal BufferedBerOctetStream(
        BerOctetStringGenerator  gen,
        byte[]          buf)
      {
        _gen = gen;
        _buf = buf;
        _off = 0;
        _derOut = new DerOutputStream(_gen.Out);
      }

      public override void WriteByte(
        byte b)
      {
        _buf[_off++] = b;

        if (_off == _buf.Length)
        {
          DerOctetString.Encode(_derOut, _buf, 0, _off);
          _off = 0;
        }
      }

      public override void Write(
        byte[] buf,
        int    offset,
        int    len)
      {
        while (len > 0)
        {
          int numToCopy = System.Math.Min(len, _buf.Length - _off);

          if (numToCopy == _buf.Length)
          {
            DerOctetString.Encode(_derOut, buf, offset, numToCopy);
          }
          else
          {
            Array.Copy(buf, offset, _buf, _off, numToCopy);

            _off += numToCopy;
            if (_off < _buf.Length)
              break;

            DerOctetString.Encode(_derOut, _buf, 0, _off);
            _off = 0;
          }

          offset += numToCopy;
          len -= numToCopy;
        }
      }

      public override void Close()
      {
        if (_off != 0)
        {
          DerOctetString.Encode(_derOut, _buf, 0, _off);
        }

        _gen.WriteBerEnd();
        base.Close();
      }
    }
  }
}