// Public Constructors
public Asn1Tag(Stream dataStream) : base()
{
Byte b = ReadByte(dataStream);
tagNumber = GetNumber(b);
tagType = GetType(b);
tagClass = GetClass(b);
if (tagNumber == Asn1TagNumber.HIGHNUMBER)
{
UInt32 tagNo = 0;
b = ReadByte(dataStream);
if ((b & 0x7F) == 0x00)
{
throw new IOException("Invalid tag number!");
}
else
{
while ((b & 0x80) == 0x80)
{
// Get bits from intermdeiate octets
tagNo |= (UInt32)(b & 0x7F);
tagNo <<= 7;
// Read next byte from dataStream
b = ReadByte(dataStream);
}
// Get bits from last octet
tagNo |= (UInt32)(b & 0x7F);
}
tagNumber = (Asn1TagNumber)tagNo;
}
}
public static Asn1Node ReadNode(Stream stream)
{
var identifier = stream.ReadByte();
Asn1UniversalNodeType type = (Asn1UniversalNodeType)(identifier & 0x1f);
Asn1TagClass tagClass = (Asn1TagClass)(identifier >> 6);
Asn1TagForm tagForm = (Asn1TagForm)((identifier >> 5) & 1);
int?length = ReadTagLength(stream);
if (identifier == 0 && length == 0)
{
return(null); // EOC detected
}
if (length > stream.Length)
{
throw new Asn1ParsingException($"Try to read more bytes from stream than exists {length} > {stream.Length}");
}
if (length != null)
{
var data = new byte[(int)length];
stream.Read(data, 0, (int)length);
stream = new MemoryStream(data);
if (tagClass == Asn1TagClass.Universal)
{
var tag = ReadUniversalNode(type, tagForm, stream);
tag.TagClass = tagClass;
return(tag);
}
else
{
var tag = Asn1CustomNode.ReadFrom(type, tagForm, stream);
tag.TagClass = tagClass;
return(tag);
}
}
else
{
// We must just keep on reading the stream rather than keeping a separate memory buffer
Asn1DynamicArray tag = Asn1DynamicArray.ReadFrom(type, stream);
tag.TagClass = tagClass;
return(tag);
}
}
public Asn1Node FindSingleNode(Asn1TagClass tagClass, int tagId)
{
return(Nodes.FirstOrDefault(n => n.Is(tagClass, tagId)));
}
public bool Is(Asn1TagClass @class, int tagId)
{
return(TagClass == @class && (int)NodeType == tagId);
}
public Asn1CustomNode(int type, Asn1TagForm tagForm, Asn1TagClass tagClass)
{
Type = (Asn1UniversalNodeType)type;
TagForm = tagForm;
TagClass = tagClass;
}
// Public Constructors
public Asn1Tag( Stream dataStream )
: base()
{
Byte b = ReadByte(dataStream);
tagNumber = GetNumber(b);
tagType = GetType(b);
tagClass = GetClass(b);
if (tagNumber == Asn1TagNumber.HIGHNUMBER)
{
UInt32 tagNo = 0;
b = ReadByte(dataStream);
if ((b & 0x7F) == 0x00)
throw new IOException("Invalid tag number!");
else
{
while ((b & 0x80) == 0x80)
{
// Get bits from intermdeiate octets
tagNo |= (UInt32)(b & 0x7F);
tagNo <<= 7;
// Read next byte from dataStream
b = ReadByte(dataStream);
}
// Get bits from last octet
tagNo |= (UInt32) (b & 0x7F);
}
tagNumber = (Asn1TagNumber) tagNo;
}
}
