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

namespace Org.BouncyCastle.Asn1{
  /**
   * DER TaggedObject - in ASN.1 notation this is any object preceded by
   * a [n] where n is some number - these are assumed to follow the construction
   * rules (as with sequences).
   */
  public class DerTaggedObject
    : Asn1TaggedObject
  {
    /**
     * @param tagNo the tag number for this object.
     * @param obj the tagged object.
     */
    public DerTaggedObject(
      int        tagNo,
      Asn1Encodable  obj)
      : base(tagNo, obj)
    {
    }

    /**
     * @param explicitly true if an explicitly tagged object.
     * @param tagNo the tag number for this object.
     * @param obj the tagged object.
     */
    public DerTaggedObject(
      bool      explicitly,
      int        tagNo,
      Asn1Encodable  obj)
      : base(explicitly, tagNo, obj)
    {
    }

    /**
     * create an implicitly tagged object that contains a zero
     * length sequence.
     */
    public DerTaggedObject(
      int tagNo)
      : base(false, tagNo, DerSequence.Empty)
    {
    }

    internal override void Encode(
      DerOutputStream derOut)
    {
      if (!IsEmpty())
      {
        byte[] bytes = obj.GetDerEncoded();

        if (explicitly)
        {
          derOut.WriteEncoded(Asn1Tags.Constructed | Asn1Tags.Tagged, tagNo, bytes);
        }
        else
        {
          //
          // need to mark constructed types... (preserve Constructed tag)
          //
          int flags = (bytes[0] & Asn1Tags.Constructed) | Asn1Tags.Tagged;
          derOut.WriteTag(flags, tagNo);
          derOut.Write(bytes, 1, bytes.Length - 1);
        }
      }
      else
      {
        derOut.WriteEncoded(Asn1Tags.Constructed | Asn1Tags.Tagged, tagNo, new byte[0]);
      }
    }
  }
}