com.tencent.kona.sun.security.util

Class DerInputStream

java.lang.Object

com.tencent.kona.sun.security.util.DerInputStream

public class DerInputStream
extends java.lang.Object

A DER input stream, used for parsing ASN.1 DER-encoded data such as that found in X.509 certificates. DER is a subset of BER/1, which has the advantage that it allows only a single encoding of primitive data. (High level data such as dates still support many encodings.) That is, it uses the "Definite" Encoding Rules (DER) not the "Basic" ones (BER).

Note that, like BER/1, DER streams are streams of explicitly tagged data values. Accordingly, this programming interface does not expose any variant of the java.io.InputStream interface, since that kind of input stream holds untagged data values and using that I/O model could prevent correct parsing of the DER data.

At this time, this class supports only a subset of the types of DER data encodings which are defined. That subset is sufficient for parsing most X.509 certificates.

Constructor Summary

Constructors

Constructor and Description
DerInputStream(byte[] data)
DerInputStream(byte[] data, int offset, int len)
DerInputStream(byte[] data, int start, int length, boolean allowBER) Constructs a DerInputStream by assigning all its fields.

Method Summary

Modifier and Type	Method and Description
void	atEnd() Ensures there is no more data.
int	available() Returns the number of bytes available for reading.
java.math.BigInteger	getBigInteger()
byte[]	getBitString()
java.lang.String	getBMPString()
DerValue	getDerValue() Reads a DerValue from this stream.
int	getEnumerated()
java.util.Date	getGeneralizedTime()
java.lang.String	getGeneralString()
java.lang.String	getIA5String()
int	getInteger()
void	getNull()
byte[]	getOctetString()
ObjectIdentifier	getOID()
java.util.Optional<DerValue>	getOptional(byte tag) Returns the next DerValue if its tag is the given one.
java.util.Optional<DerValue>	getOptionalExplicitContextSpecific(int n) Returns the inner DerValue if the next DerValue is an EXPLICIT context-specific value tagged by n.
java.util.Optional<DerValue>	getOptionalImplicitContextSpecific(int n, byte tag) Returns the restored DerValue if the next DerValue is an IMPLICIT context-specific value tagged by n.
java.math.BigInteger	getPositiveBigInteger()
java.lang.String	getPrintableString()
DerValue[]	getSequence(int startLen)
DerValue[]	getSet(int startLen)
DerValue[]	getSet(int startLen, boolean implicit)
java.lang.String	getT61String()
BitArray	getUnalignedBitString()
java.util.Date	getUTCTime()
java.lang.String	getUTF8String()
void	mark(int readAheadLimit) Mark the current position in the buffer, so that a later call to reset will return here.
int	peekByte()
void	reset() Return to the position of the last mark call.
boolean	seeOptionalContextSpecific(int n) Detect if the next DerValue is a context-specific value tagged by n.
byte[]	toByteArray() Returns the remaining unread bytes, or, all bytes if none read yet.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DerInputStream

public DerInputStream(byte[] data,
                      int start,
                      int length,
                      boolean allowBER)

Constructs a DerInputStream by assigning all its fields. No checking on arguments since all callers are internal. data should never be null even if length is 0.

DerInputStream

public DerInputStream(byte[] data)
               throws java.io.IOException

Throws:

java.io.IOException

DerInputStream

public DerInputStream(byte[] data,
                      int offset,
                      int len)
               throws java.io.IOException

Throws:

java.io.IOException

Method Detail

toByteArray

public byte[] toByteArray()

Returns the remaining unread bytes, or, all bytes if none read yet.

getDerValue

public DerValue getDerValue()
                     throws java.io.IOException

Reads a DerValue from this stream. After the call, the data pointer is right after this DerValue so that the next call will read the next DerValue.

Returns:

the read DerValue.

Throws:

java.io.IOException - if a DerValue cannot be constructed starting from this position because of byte shortage or encoding error.

getInteger

public int getInteger()
               throws java.io.IOException

Throws:

java.io.IOException

getBigInteger

public java.math.BigInteger getBigInteger()
                                   throws java.io.IOException

Throws:

java.io.IOException

getPositiveBigInteger

public java.math.BigInteger getPositiveBigInteger()
                                           throws java.io.IOException

Throws:

java.io.IOException

getEnumerated

public int getEnumerated()
                  throws java.io.IOException

Throws:

java.io.IOException

getBitString

public byte[] getBitString()
                    throws java.io.IOException

Throws:

java.io.IOException

getUnalignedBitString

public BitArray getUnalignedBitString()
                               throws java.io.IOException

Throws:

java.io.IOException

getOctetString

public byte[] getOctetString()
                      throws java.io.IOException

Throws:

java.io.IOException

getNull

public void getNull()
             throws java.io.IOException

Throws:

java.io.IOException

getOID

public ObjectIdentifier getOID()
                        throws java.io.IOException

Throws:

java.io.IOException

getUTF8String

public java.lang.String getUTF8String()
                               throws java.io.IOException

Throws:

java.io.IOException

getPrintableString

public java.lang.String getPrintableString()
                                    throws java.io.IOException

Throws:

java.io.IOException

getT61String

public java.lang.String getT61String()
                              throws java.io.IOException

Throws:

java.io.IOException

getBMPString

public java.lang.String getBMPString()
                              throws java.io.IOException

Throws:

java.io.IOException

getIA5String

public java.lang.String getIA5String()
                              throws java.io.IOException

Throws:

java.io.IOException

getGeneralString

public java.lang.String getGeneralString()
                                  throws java.io.IOException

Throws:

java.io.IOException

getUTCTime

public java.util.Date getUTCTime()
                          throws java.io.IOException

Throws:

java.io.IOException

getGeneralizedTime

public java.util.Date getGeneralizedTime()
                                  throws java.io.IOException

Throws:

java.io.IOException

getSequence

public DerValue[] getSequence(int startLen)
                       throws java.io.IOException

Throws:

java.io.IOException

getSet

public DerValue[] getSet(int startLen)
                  throws java.io.IOException

Throws:

java.io.IOException

getSet

public DerValue[] getSet(int startLen,
                         boolean implicit)
                  throws java.io.IOException

Throws:

java.io.IOException

peekByte

public int peekByte()
             throws java.io.IOException

Throws:

java.io.IOException

mark

public void mark(int readAheadLimit)

Mark the current position in the buffer, so that a later call to reset will return here. The readAheadLimit is useless here, because all data is available, and we can go to anywhere at will.

reset

public void reset()

Return to the position of the last mark call. A mark is implicitly set at the beginning of the stream when it is created.

available

public int available()

Returns the number of bytes available for reading. This is most useful for testing whether the stream is empty.

atEnd

public void atEnd()
           throws java.io.IOException

Ensures there is no more data. This can be called when the last expected field is parsed, and we need to make sure no unread is left.

Throws:

java.io.IOException - if the end is NOT reached yet

getOptional

public java.util.Optional<DerValue> getOptional(byte tag)
                                         throws java.io.IOException

Returns the next DerValue if its tag is the given one.

Parameters:

tag - the expected tag

Returns:

the next DerValue, or empty if not found or stream at end

Throws:

java.io.IOException - if an I/O error happens

seeOptionalContextSpecific

public boolean seeOptionalContextSpecific(int n)
                                   throws java.io.IOException

Detect if the next DerValue is a context-specific value tagged by n.

Parameters:

n - the expected tag

Returns:

true if matches, false if not or stream is at end.

Throws:

java.io.IOException - if an I/O error happens while peeking the byte

getOptionalExplicitContextSpecific

public java.util.Optional<DerValue> getOptionalExplicitContextSpecific(int n)
                                                                throws java.io.IOException

Returns the inner DerValue if the next DerValue is an EXPLICIT context-specific value tagged by n.

Parameters:

n - the expected tag

Returns:

the inner DerValue, or empty if not found or stream at end

Throws:

java.io.IOException - if an I/O error happens

getOptionalImplicitContextSpecific

public java.util.Optional<DerValue> getOptionalImplicitContextSpecific(int n,
                                                                       byte tag)
                                                                throws java.io.IOException

Returns the restored DerValue if the next DerValue is an IMPLICIT context-specific value tagged by n.

Parameters:

n - the expected tag

tag - the real tag for the IMPLICIT type

Returns:

the restored DerValue, or empty if not found or stream at end

Throws:

java.io.IOException - if an I/O error happens