Asn1BerDecodeBuffer Class Reference

Inheritance diagram for Asn1BerDecodeBuffer:

Public Member Functions
	Asn1BerDecodeBuffer (System.IO.Stream istream)
	Asn1BerDecodeBuffer (byte[] msgdata)
int	DecodeEnumValue (Asn1Tag tag, bool explicitTagging, int implicitLength)
int	DecodeEnumValue (bool explicitTagging, int implicitLength)
virtual int	DecodeLength ()
virtual byte[]	DecodeOpenType (bool saveData)
virtual byte[]	DecodeOpenType ()
virtual void	DecodeTag (Asn1Tag tag)
virtual int	DecodeTagAndLength (Asn1Tag tag)
virtual bool	MatchTag (Asn1Tag tag)
virtual bool	MatchTag (Asn1Tag tag, Asn1Tag parsedTag, IntHolder parsedLen)
virtual bool	MatchTag (short tagClass, short tagForm, int tagIDCode, Asn1Tag parsedTag, IntHolder parsedLen)
virtual void	Parse (Asn1TaggedEventHandler handler)
virtual Asn1Tag	PeekTag ()
virtual void	PeekTag (Asn1Tag parsedTag)
override int	ReadByte ()
Static Public Member Functions
static int	CalcIndefLen (byte[] data, int offset, int len)
Protected Member Functions
internal void	MovePastEOC (bool saveData)
Properties
virtual Asn1Tag	LastTag `[get]`

Detailed Description

This class handles the decoding of ASN.1 messages as specified in the Basic Encoding Rules (BER) as documented in the ITU-T X.690 standard.

Constructor & Destructor Documentation

Asn1BerDecodeBuffer ( byte[] msgdata )

This constructor creates a BER Decode buffer object that references an encoded ASN.1 message.

Parameters:

msgdata

Byte array containing an encoded ASN.1 message.

Asn1BerDecodeBuffer ( System.IO.Stream istream )

This constructor creates a BER Decode buffer object that references an encoded ASN.1 message. In this case, the message is passed in using an System.IO.Stream object.

Parameters:

istream

Input stream containing an encoded ASN.1 message.

Member Function Documentation

static int CalcIndefLen	(	byte[]	data,
		int	offset,
		int	len
	)			`[static]`

This function calculates the actual length of an indefinite length message component.

Parameters:

	data	Buffer with the indefinite length message component.
	offset	The start offset in the array
	len	Length of the buffer (begining from the offset)

Returns:: calculated length

int DecodeEnumValue	(	Asn1Tag	tag,
		bool	explicitTagging,
		int	implicitLength
	)

This method decodes an enumerated value from the buffer.

Parameters:

	tag	An Asn1Tag value for enumerated values that are tagged other than UNIVERSAL 10.
	explicitTagging	A flag that indicates the element is explicitly tagged.
	implicitLength	The length of the contents if implicitly tagged.

Returns:: The decoded integer value.

int DecodeEnumValue	(	bool	explicitTagging,
		int	implicitLength
	)

This method decodes an enumerated value from the buffer.

Parameters:

	explicitTagging	A flag that indicates the element is explicitly tagged.
	implicitLength	The length of the contents if implicitly tagged.

Returns:: The decoded integer value.

virtual int DecodeLength ( ) [virtual]

This method decodes a length value.

Returns:: Decoded length value

virtual byte [] DecodeOpenType ( bool saveData ) [virtual]

This method decodes an ASN.1 BER open type value. This is a fully encoded message component of any type. This version of the method allows the option of saving or discarding the open type data.

Parameters:

saveData

True if data should be captured and returned

Returns:: Reference to byte array containing component.

virtual byte [] DecodeOpenType ( ) [virtual]

This method decodes an ASN.1 BER open type value. This is a fully encoded message component of any type. The component is captured in the Decode capture buffer and a reference to a byte array is returned containing the component.

Returns:: Reference to byte array containing component.

virtual void DecodeTag ( Asn1Tag tag ) [virtual]

This method decodes a tag value.

Parameters:

tag

Tag object to receive decoded tag fields.

Returns:: status value (see Asn1Status.java)

virtual int DecodeTagAndLength ( Asn1Tag tag ) [virtual]

This method decodes a tag and length value.

Parameters:

tag

Tag object to receive decoded tag fields.

Returns:: Decoded length value.

virtual bool MatchTag ( Asn1Tag tag ) [virtual]

This overloaded version of MatchTag will just test for a match and not return parsed tag and length values

Parameters:

tag

Tag value to be matched.

Returns:: True if given tag matches tag at Decode cursor

virtual bool MatchTag	(	Asn1Tag	tag,
		Asn1Tag	parsedTag,
		IntHolder	parsedLen
	)			`[virtual]`

This overloaded version of MatchTag allows the tag value to be matched to be passed using an Asn1Tag object.

Parameters:

	tag	Tag value to be matched.
	parsedTag	Holder object to receive parsed tag value
	parsedLen	Holder object to receive parsed length value

Returns:: True if given tag matches tag at Decode cursor

virtual bool MatchTag	(	short	tagClass,
		short	tagForm,
		int	tagIDCode,
		Asn1Tag	parsedTag,
		IntHolder	parsedLen
	)			`[virtual]`

This method decodes the next tag value and checks for a match with the given tag value. If the match is successful, the Decode cursor will be psoitioned at the contents field; otherwise, it will be reset to point to the start of the tag field.

Parameters:

	tagClass	Class value of tag to match
	tagForm	Form value of tag to match
	tagIDCode	ID code of tag to match
	parsedTag	Holder object to receive parsed tag value
	parsedLen	Holder object to receive parsed length value

Returns:: True if given tag matches tag at Decode cursor

internal void MovePastEOC ( bool saveData ) [protected]

This method skips or saves the data/bytes of the current tag in this DecodeBuffer. If current tag has indefinite length, than index will moved to end of the indifinite length. If tag has definite length, than that many bytes are moved.

Parameters:

saveData

True if data should be captured

virtual void Parse ( Asn1TaggedEventHandler handler ) [virtual]

This method parses the complete message and invokes the event handler callback methods as various items are encountered.

Parameters:

handler

Object implementing the Asn1EventHandler interface.

Returns:: Status value

virtual Asn1Tag PeekTag ( ) [virtual]

This overloaded version of the PeekTag method will return a reference to a newly created tag object.

Returns:: Parsed tag object value reference

virtual void PeekTag ( Asn1Tag parsedTag ) [virtual]

This method will Parse and return the next tag in the Decode stream without advancing the Decode cursor.

Parameters:

parsedTag

Holder object to receive parsed tag value

override int ReadByte ( ) [virtual]

This method returns the next available 8-bit value from the input stream. It is implemented differently for BER/DER and PER to take into account odd alignments in PER.

Returns:: Next 8-bit byte value from input stream

Implements Asn1DecodeBuffer.

Property Documentation

virtual Asn1Tag LastTag [get]

Gets the last tag parsed within this decode buffer object.

Value: Last parsed tag object reference

Asn1BerDecodeBuffer Class Reference

Public Member Functions

Static Public Member Functions

Protected Member Functions

Properties

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Property Documentation