public virtual IAsn1Convertible ReadObject()
{
int tag = _in.ReadByte();
if (tag == -1)
{
return(null);
}
// turn of looking for "00" while we resolve the tag
Set00Check(false);
//
// calculate tag number
//
int tagNo = Asn1InputStream.ReadTagNumber(_in, tag);
bool isConstructed = (tag & Asn1Tags.Constructed) != 0;
//
// calculate length
//
int length = Asn1InputStream.ReadLength(_in, _limit);
if (length < 0) // indefinite length method
{
if (!isConstructed)
{
throw new IOException("indefinite length primitive encoding encountered");
}
IndefiniteLengthInputStream indIn = new IndefiniteLengthInputStream(_in, _limit);
Asn1StreamParser sp = new Asn1StreamParser(indIn, _limit);
if ((tag & Asn1Tags.Application) != 0)
{
return(new BerApplicationSpecificParser(tagNo, sp));
}
if ((tag & Asn1Tags.Tagged) != 0)
{
return(new BerTaggedObjectParser(true, tagNo, sp));
}
return(sp.ReadIndef(tagNo));
}
else
{
DefiniteLengthInputStream defIn = new DefiniteLengthInputStream(_in, length);
if ((tag & Asn1Tags.Application) != 0)
{
return(new DerApplicationSpecific(isConstructed, tagNo, defIn.ToArray()));
}
if ((tag & Asn1Tags.Tagged) != 0)
{
return(new BerTaggedObjectParser(isConstructed, tagNo, new Asn1StreamParser(defIn)));
}
if (isConstructed)
{
// TODO There are other tags that may be constructed (e.g. BitString)
switch (tagNo)
{
case Asn1Tags.OctetString:
//
// yes, people actually do this...
//
return(new BerOctetStringParser(new Asn1StreamParser(defIn)));
case Asn1Tags.Sequence:
return(new DerSequenceParser(new Asn1StreamParser(defIn)));
case Asn1Tags.Set:
return(new DerSetParser(new Asn1StreamParser(defIn)));
case Asn1Tags.External:
return(new DerExternalParser(new Asn1StreamParser(defIn)));
default:
// TODO Add DerUnknownTagParser class?
return(new DerUnknownTag(true, tagNo, defIn.ToArray()));
}
}
// Some primitive encodings can be handled by parsers too...
switch (tagNo)
{
case Asn1Tags.OctetString:
return(new DerOctetStringParser(defIn));
}
try
{
return(Asn1InputStream.CreatePrimitiveDerObject(tagNo, defIn.ToArray()));
}
catch (ArgumentException e)
{
throw new Asn1Exception("corrupted stream detected", e);
}
}
}
public Asn1StreamParser(
Stream inStream)
: this(inStream, Asn1InputStream.FindLimit(inStream))
{
}