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

using System;
using System.IO;

namespace Org.BouncyCastle.Asn1.Cms{
  /**
  * <pre>
  * SignedData ::= SEQUENCE {
  *     version CMSVersion,
  *     digestAlgorithms DigestAlgorithmIdentifiers,
  *     encapContentInfo EncapsulatedContentInfo,
  *     certificates [0] IMPLICIT CertificateSet OPTIONAL,
  *     crls [1] IMPLICIT CertificateRevocationLists OPTIONAL,
  *     signerInfos SignerInfos
  *   }
  * </pre>
  */
  public class SignedDataParser
  {
    private Asn1SequenceParser  _seq;
    private DerInteger      _version;
    private object        _nextObject;
    private bool        _certsCalled;
    private bool        _crlsCalled;

    public static SignedDataParser GetInstance(
      object o)
    {
      if (o is Asn1Sequence)
        return new SignedDataParser(((Asn1Sequence)o).Parser);

      if (o is Asn1SequenceParser)
        return new SignedDataParser((Asn1SequenceParser)o);

      throw new IOException("unknown object encountered: " + o.GetType().Name);
    }

    public SignedDataParser(
      Asn1SequenceParser seq)
    {
      this._seq = seq;
      this._version = (DerInteger)seq.ReadObject();
    }

    public DerInteger Version
    {
      get { return _version; }
    }

    public Asn1SetParser GetDigestAlgorithms()
    {
      return (Asn1SetParser)_seq.ReadObject();
    }

    public ContentInfoParser GetEncapContentInfo()
    {
      return new ContentInfoParser((Asn1SequenceParser)_seq.ReadObject());
    }

    public Asn1SetParser GetCertificates()
    {
      _certsCalled = true;
      _nextObject = _seq.ReadObject();

      if (_nextObject is Asn1TaggedObjectParser && ((Asn1TaggedObjectParser)_nextObject).TagNo == 0)
      {
        Asn1SetParser certs = (Asn1SetParser)((Asn1TaggedObjectParser)_nextObject).GetObjectParser(Asn1Tags.Set, false);
        _nextObject = null;

        return certs;
      }

      return null;
    }

    public Asn1SetParser GetCrls()
    {
      if (!_certsCalled)
        throw new IOException("GetCerts() has not been called.");

      _crlsCalled = true;

      if (_nextObject == null)
      {
        _nextObject = _seq.ReadObject();
      }

      if (_nextObject is Asn1TaggedObjectParser && ((Asn1TaggedObjectParser)_nextObject).TagNo == 1)
      {
        Asn1SetParser crls = (Asn1SetParser)((Asn1TaggedObjectParser)_nextObject).GetObjectParser(Asn1Tags.Set, false);
        _nextObject = null;

        return crls;
      }

      return null;
    }

    public Asn1SetParser GetSignerInfos()
    {
      if (!_certsCalled || !_crlsCalled)
        throw new IOException("GetCerts() and/or GetCrls() has not been called.");

      if (_nextObject == null)
      {
        _nextObject = _seq.ReadObject();
      }

      return (Asn1SetParser)_nextObject;
    }
  }
}