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

using System;
using System.IO;

using Org.BouncyCastle.Asn1.Utilities;

namespace Org.BouncyCastle.Asn1{
  public class DerOutputStream
    : FilterStream
  {
    public DerOutputStream(Stream os)
      : base(os)
    {
    }

    private void WriteLength(
      int length)
    {
      if (length > 127)
      {
        int size = 1;
        uint val = (uint) length;

        while ((val >>= 8) != 0)
        {
          size++;
        }

        WriteByte((byte)(size | 0x80));

        for (int i = (size - 1) * 8; i >= 0; i -= 8)
        {
          WriteByte((byte)(length >> i));
        }
      }
      else
      {
        WriteByte((byte)length);
      }
    }

    internal void WriteEncoded(
      int    tag,
      byte[]  bytes)
    {
      WriteByte((byte) tag);
      WriteLength(bytes.Length);
      Write(bytes, 0, bytes.Length);
    }

    internal void WriteEncoded(
      int    tag,
      byte[]  bytes,
      int    offset,
      int    length)
    {
      WriteByte((byte) tag);
      WriteLength(length);
      Write(bytes, offset, length);
    }

    internal void WriteTag(
      int  flags,
      int  tagNo)
    {
      if (tagNo < 31)
      {
        WriteByte((byte)(flags | tagNo));
      }
      else
      {
        WriteByte((byte)(flags | 0x1f));
        if (tagNo < 128)
        {
          WriteByte((byte)tagNo);
        }
        else
        {
          byte[] stack = new byte[5];
          int pos = stack.Length;

          stack[--pos] = (byte)(tagNo & 0x7F);

          do
          {
            tagNo >>= 7;
            stack[--pos] = (byte)(tagNo & 0x7F | 0x80);
          }
          while (tagNo > 127);

          Write(stack, pos, stack.Length - pos);
        }
      }
    }

    internal void WriteEncoded(
      int    flags,
      int    tagNo,
      byte[]  bytes)
    {
      WriteTag(flags, tagNo);
      WriteLength(bytes.Length);
      Write(bytes, 0, bytes.Length);
    }

    protected void WriteNull()
    {
      WriteByte(Asn1Tags.Null);
      WriteByte(0x00);
    }

    [Obsolete("Use version taking an Asn1Encodable arg instead")]
    public virtual void WriteObject(
      object obj)
    {
      if (obj == null)
      {
        WriteNull();
      }
      else if (obj is Asn1Object)
      {
        ((Asn1Object)obj).Encode(this);
      }
      else if (obj is Asn1Encodable)
      {
        ((Asn1Encodable)obj).ToAsn1Object().Encode(this);
      }
      else
      {
        throw new IOException("object not Asn1Object");
      }
    }

    public virtual void WriteObject(
      Asn1Encodable obj)
    {
      if (obj == null)
      {
        WriteNull();
      }
      else
      {
        obj.ToAsn1Object().Encode(this);
      }
    }

    public virtual void WriteObject(
      Asn1Object obj)
    {
      if (obj == null)
      {
        WriteNull();
      }
      else
      {
        obj.Encode(this);
      }
    }
  }
}