Class AsnReader

Reads DER-encoded ASN.1 data (X.690). Cursor-based, forward-only. Constructed types return a new AsnReader scoped to the element's content.

Inheritance

object

AsnReader

Inherited Members

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

object.GetType()

Namespace: DRIT.Mail.Rfc.Crypto.Asn1

Assembly: DRIT.Mail.dll

Syntax

public sealed class AsnReader

Constructors

AsnReader(byte[])

Initializes a new instance of the AsnReader class over the given byte array.

Declaration

public AsnReader(byte[] data)

Parameters

Type	Name	Description
byte[]	data	The data to process.

AsnReader(byte[], int, int)

Initializes a new instance of the AsnReader class over a slice of the given byte array.

Declaration

public AsnReader(byte[] data, int offset, int length)

Parameters

Type	Name	Description
byte[]	data	The data to process.
int	offset	The offset within the data.
int	length	The length value.

Properties

HasData

Gets a value indicating whether this reader has any data left to read.

Declaration

public bool HasData { get; }

Property Value

Type	Description
bool

Position

Gets the current cursor position relative to the start of this reader's slice.

Declaration

public int Position { get; }

Property Value

Type	Description
int

Remaining

Gets the number of bytes remaining in this reader.

Declaration

public int Remaining { get; }

Property Value

Type	Description
int

Methods

IsContextTag(byte)

Determines whether the next tag is the given context tag number (0–30), regardless of constructed/primitive form.

Declaration

public bool IsContextTag(byte expectedTag)

Parameters

Type	Name	Description
byte	expectedTag	The expected tag used by the operation.

Returns

Type	Description
bool

PeekTag()

Peeks at the next tag byte without advancing the cursor. Throws if no data.

Declaration

public byte PeekTag()

Returns

Type	Description
byte

ReadBitString()

Reads a BIT STRING, stripping the unused-bits prefix byte. Returns the bit content bytes.

Declaration

public byte[] ReadBitString()

Returns

Type	Description
byte[]

ReadBoolean()

Reads a BOOLEAN.

Declaration

public bool ReadBoolean()

Returns

Type	Description
bool

ReadExplicit(byte)

Reads an EXPLICIT context-tagged element [tag] and returns a new reader over its content. The tag is the context tag number (0–30).

Declaration

public AsnReader ReadExplicit(byte tag)

Parameters

Type	Name	Description
byte	tag	Specifies the tag value.

Returns

Type	Description
AsnReader

ReadGeneralizedTime()

Reads a GeneralizedTime and returns a UTC DateTime.

Declaration

public DateTime ReadGeneralizedTime()

Returns

Type	Description
DateTime

ReadIa5String()

Reads an IA5String (ASCII).

Declaration

public string ReadIa5String()

Returns

Type	Description
string

ReadImplicit(byte)

Reads an IMPLICIT context-tagged element and returns its raw TLV bytes (tag + length + content).

Declaration

public byte[] ReadImplicit(byte tag)

Parameters

Type	Name	Description
byte	tag	Specifies the tag value.

Returns

Type	Description
byte[]

ReadInt32()

Reads an INTEGER as a 32-bit signed value. Throws if the value is out of range.

Declaration

public int ReadInt32()

Returns

Type	Description
int

ReadInteger()

Reads an INTEGER as big-endian bytes (arbitrary size). The result preserves the sign by including a leading 0x00 byte when the high bit of the most significant byte would otherwise be set for a positive value.

Declaration

public byte[] ReadInteger()

Returns

Type	Description
byte[]

ReadNull()

Reads a NULL and returns nothing. Throws if the element is not NULL.

Declaration

public void ReadNull()

ReadOctetString()

Reads an OCTET STRING.

Declaration

public byte[] ReadOctetString()

Returns

Type	Description
byte[]

ReadOid()

Reads an OBJECT IDENTIFIER as a dotted-decimal string.

Declaration

public string ReadOid()

Returns

Type	Description
string

ReadPrintableString()

Reads a PrintableString.

Declaration

public string ReadPrintableString()

Returns

Type	Description
string

ReadRawTlv()

Reads a full Tag-Length-Value triple and returns the complete raw bytes (tag + length + content). Advances the cursor past the element.

Declaration

public byte[] ReadRawTlv()

Returns

Type	Description
byte[]

ReadSequence()

Reads a SEQUENCE and returns a new reader over its content.

Declaration

public AsnReader ReadSequence()

Returns

Type	Description
AsnReader

ReadSet()

Reads a SET and returns a new reader over its content.

Declaration

public AsnReader ReadSet()

Returns

Type	Description
AsnReader

ReadTlv()

Reads a full Tag-Length-Value triple, returning the tag byte and the content bytes (a copy). Advances the cursor past the element.

Declaration

public (byte tag, byte[] content) ReadTlv()

Returns

Type	Description
(byte tag, byte[] content)

ReadUtcTime()

Reads a UTCTime and returns a UTC DateTime.

Declaration

public DateTime ReadUtcTime()

Returns

Type	Description
DateTime

ReadUtf8String()

Reads a UTF8String.

Declaration

public string ReadUtf8String()

Returns

Type	Description
string

Skip()

Skips the next element without parsing it.

Declaration

public void Skip()