org.apache.directory.api.asn1.util

Class Oid

java.lang.Object

org.apache.directory.api.asn1.util.Oid

public final class Oid
extends Object

An immutable representation of an object identifier that provides conversion between their String, and encoded byte[] representations.

The encoding of OID values is performed according to itu X.690 section 8.19. Specifically:

8.19.2 The contents octets shall be an (ordered) list of encodings of subidentifiers (see 8.19.3 and 8.19.4) concatenated together. Each subidentifier is represented as a series of (one or more) octets. Bit 8 of each octet indicates whether it is the last in the series: bit 8 of the last octet is zero; bit 8 of each preceding octet is one. Bits 7 to 1 of the octets in the series collectively encode the subidentifier. Conceptually, these groups of bits are concatenated to form an unsigned binary number whose most significant bit is bit 7 of the first octet and whose least significant bit is bit 1 of the last octet. The subidentifier shall be encoded in the fewest possible octets, that is, the leading octet of the subidentifier shall not have the value 0x80.

8.19.3 The number of subidentifiers (N) shall be one less than the number of object identifier components in the object identifier value being encoded.

8.19.4 The numerical value of the first subidentifier is derived from the values of the first two object identifier components in the object identifier value being encoded, using the formula:
(X*40) + Y
where X is the value of the first object identifier component and Y is the value of the second object identifier component. NOTE – This packing of the first two object identifier components recognizes that only three values are allocated from the root node, and at most 39 subsequent values from nodes reached by X = 0 and X = 1.

For example, the OID "2.12.3456.7" would be turned into a list of 3 values: [((2*40)+12), 3456, 7]. The first of which, 92, would be encoded as the bytes 0x5C, the second would be [0x9B, 0x00], and the third as 0x07 giving the final encoding [0x5C, 0x9B, 0x00, 0x07].

Author:

Apache Directory Project

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	Oid.OidFSAState The OID FSA states.

Field Summary

Fields

Modifier and Type	Field and Description
private static BigInteger	JOINT_ISO_ITU_T
private byte[]	oidBytes A byte[] representation of an OID
private String	oidString The OID as a String

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Oid(String oidString, byte[] oidBytes) Creates a new instance of Oid.

Method Summary

Modifier and Type	Method and Description
private static int	convert(String oid, byte[] buffer, int start, int nbDigits, int posBuffer, boolean isJointIsoItuT) Convert a list of digits to a list of 7 bits bytes.
boolean	equals(Object other)
static Oid	fromBytes(byte[] oidBytes) Decodes an OID from a byte[].
static Oid	fromString(String oidString) Returns an OID object representing oidString.
int	getEncodedLength() Returns the length of the encoded byte[] representation.
int	hashCode()
static boolean	isOid(String oidString) Returns true if oidString is a valid string representation of an OID.
private static Oid.OidFSAState	processStateA(String oid, int pos) Process state B (A) --['.']
private static Oid.OidFSAState	processStateB(String oid, byte[] buffer, int pos) Process state B (B) --['0']--> (D) (B) --['1'..'3']--> (C) (B) --['4'..'9']--> (E)
private static Oid.OidFSAState	processStateC(String oid, byte[] buffer, int pos) Process state C (C) --['.']
private static Oid.OidFSAState	processStateDE(String oid, byte[] buffer, int pos) Process state D and E (D) --['.']
private static Oid.OidFSAState	processStateF(String oid, int pos) Process state F (F) --['.']
private static Oid.OidFSAState	processStateG(String oid, byte[] buffer, int pos) Process state G (G) --['0']--> (I) (G) --['1'..'9']--> (H)
private static Oid.OidFSAState	processStateH(String oid, byte[] buffer, int pos) Process state H (H) --['.']
private static Oid.OidFSAState	processStateI(String oid, byte[] buffer, int pos) Process state I (I) --['.']
private static Oid.OidFSAState	processStateJ(String oid, byte[] buffer, int bufferPos, int pos) Process state J (J) --['.']
private static Oid.OidFSAState	processStateK(String oid, byte[] buffer, int bufferPos, int pos) Process state J (K) --['0']--> (M) (K) --['1'..'9']--> (L)
private static Oid.OidFSAState	processStateL(String oid, byte[] buffer, int bufferPos, int pos) Process state J (L) --['.']
private static Oid.OidFSAState	processStateM(String oid, int pos) Process state J (M) --['.']
private static Oid.OidFSAState	processStateStart(String oid, byte[] buffer, int pos) Process state A (Start) --['0','1']--> (A) (start) --['2']--> (F)
byte[]	toBytes() Returns the byte[] representation of the OID.
String	toString() Returns the string representation of the OID.
void	writeBytesTo(ByteBuffer buffer) Writes the bytes respresenting this OID to the provided buffer.
void	writeBytesTo(OutputStream outputStream) Writes the bytes respresenting this OID to the provided stream.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

oidBytes

private byte[] oidBytes

A byte[] representation of an OID

oidString

private String oidString

The OID as a String

JOINT_ISO_ITU_T

private static final BigInteger JOINT_ISO_ITU_T

Constructor Detail

Oid

private Oid(String oidString,
            byte[] oidBytes)

Creates a new instance of Oid.

Parameters:

oidString - The OID as a String

oidBytes - The OID as a byte[]

Method Detail

equals

public boolean equals(Object other)

Overrides:

equals in class Object

fromBytes

public static Oid fromBytes(byte[] oidBytes)
                     throws DecoderException

Decodes an OID from a byte[].

Parameters:

oidBytes - The encodedbyte[]

Returns:

A new Oid

Throws:

DecoderException - When the OID is not valid

processStateStart

private static Oid.OidFSAState processStateStart(String oid,
                                                 byte[] buffer,
                                                 int pos)
                                          throws DecoderException

Process state A

 (Start) --['0','1']--> (A)
 (start) --['2']--> (F)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateA

private static Oid.OidFSAState processStateA(String oid,
                                             int pos)
                                      throws DecoderException

Process state B

 (A) --['.']--> (B)
 

Parameters:

oid - The OID to check

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateB

private static Oid.OidFSAState processStateB(String oid,
                                             byte[] buffer,
                                             int pos)
                                      throws DecoderException

Process state B

 (B) --['0']--> (D)
 (B) --['1'..'3']--> (C)
 (B) --['4'..'9']--> (E)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateC

private static Oid.OidFSAState processStateC(String oid,
                                             byte[] buffer,
                                             int pos)
                                      throws DecoderException

Process state C

 (C) --['.']--> (K)
 (C) --['0'..'9']--> (E)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateDE

private static Oid.OidFSAState processStateDE(String oid,
                                              byte[] buffer,
                                              int pos)
                                       throws DecoderException

Process state D and E

 (D) --['.']--> (K)
 (E) --['.']--> (K)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateF

private static Oid.OidFSAState processStateF(String oid,
                                             int pos)
                                      throws DecoderException

Process state F

 (F) --['.']--> (G)
 

Parameters:

oid - The OID to check

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateG

private static Oid.OidFSAState processStateG(String oid,
                                             byte[] buffer,
                                             int pos)
                                      throws DecoderException

Process state G

 (G) --['0']--> (I)
 (G) --['1'..'9']--> (H)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateH

private static Oid.OidFSAState processStateH(String oid,
                                             byte[] buffer,
                                             int pos)
                                      throws DecoderException

Process state H

 (H) --['.']--> (K)
 (H) --['0'..'9']--> (J)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateI

private static Oid.OidFSAState processStateI(String oid,
                                             byte[] buffer,
                                             int pos)
                                      throws DecoderException

Process state I

 (I) --['.']--> (K)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateJ

private static Oid.OidFSAState processStateJ(String oid,
                                             byte[] buffer,
                                             int bufferPos,
                                             int pos)
                                      throws DecoderException

Process state J

 (J) --['.']--> (K)
 (J) --['0'..'9']--> (J)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

bufferPos - The current position in the buffer

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateK

private static Oid.OidFSAState processStateK(String oid,
                                             byte[] buffer,
                                             int bufferPos,
                                             int pos)
                                      throws DecoderException

Process state J

 (K) --['0']--> (M)
 (K) --['1'..'9']--> (L)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

bufferPos - The current position in the buffer

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateL

private static Oid.OidFSAState processStateL(String oid,
                                             byte[] buffer,
                                             int bufferPos,
                                             int pos)
                                      throws DecoderException

Process state J

 (L) --['.']--> (K)
 (L) --['0'..'9']--> (L)
 

Parameters:

oid - The OID to check

buffer - The buffer gathering the binary OID

bufferPos - The current position in the buffer

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

processStateM

private static Oid.OidFSAState processStateM(String oid,
                                             int pos)
                                      throws DecoderException

Process state J

 (M) --['.']--> (K)
 

Parameters:

oid - The OID to check

pos - The position in the OID string

Returns:

The next OID decoding state

Throws:

DecoderException - If the OID is invalid

convert

private static int convert(String oid,
                           byte[] buffer,
                           int start,
                           int nbDigits,
                           int posBuffer,
                           boolean isJointIsoItuT)

Convert a list of digits to a list of 7 bits bytes. We must start by the end, and we don't know how many bytes we will need, except when we will be done with the conversion.

Parameters:

oid - The OID to convert

buffer - The buffer gathering the binary OID

start - The starting position in the OID string

nbDigits - Teh number of digits the OID has

posBuffer - The position in the buffer

isJointIsoItuT - A flag set if we know the OID is a JointIsoItuT OID

Returns:

The number of bytes required to store the OID in a PDU

fromString

public static Oid fromString(String oidString)
                      throws DecoderException

Returns an OID object representing oidString.

Parameters:

oidString - The string representation of the OID

Returns:

A new Oid

Throws:

DecoderException - When the OID is not valid

getEncodedLength

public int getEncodedLength()

Returns the length of the encoded byte[] representation.

Returns:

The length of the byte[]

hashCode

public int hashCode()

Overrides:

hashCode in class Object

isOid

public static boolean isOid(String oidString)

Returns true if oidString is a valid string representation of an OID. This method simply calls fromString(String) and returns true if no exception was thrown. As such, it should not be used in an attempt to check if a string is a valid OID before calling fromString(String).

Parameters:

oidString - The string to test

Returns:

True, if oidString is valid

toBytes

public byte[] toBytes()

Returns the byte[] representation of the OID. The byte[] that is returned is copied from the internal value so as to preserve the immutability of an OID object. If the output of a call to this method is intended to be written to a stream, the writeBytesTo(OutputStream) should be used instead as it will avoid creating this copy.

Returns:

The encoded byte[] representation of the OID.

toString

public String toString()

Returns the string representation of the OID.

Overrides:

toString in class Object

Returns:

The string representation of the OID

writeBytesTo

public void writeBytesTo(ByteBuffer buffer)

Writes the bytes respresenting this OID to the provided buffer. This should be used in preference to the toBytes() method in order to prevent the creation of copies of the actual byte[].

Parameters:

buffer - The buffer to write the bytes into

writeBytesTo

public void writeBytesTo(OutputStream outputStream)
                  throws IOException

Writes the bytes respresenting this OID to the provided stream. This should be used in preference to the toBytes() method in order to prevent the creation of copies of the actual byte[].

Parameters:

outputStream - The stream to write the bytes to

Throws:

IOException - When we can't write the OID into a Stream