com.objsys.asn1j.runtime

Class Asn1DecodeBuffer

java.lang.Object

com.objsys.asn1j.runtime.Asn1MessageBufferBase

com.objsys.asn1j.runtime.Asn1MessageBuffer

com.objsys.asn1j.runtime.Asn1DecodeBuffer

Direct Known Subclasses:

Asn1BerDecodeBuffer, Asn1MderDecodeBuffer, Asn1PerDecodeBuffer

public abstract class Asn1DecodeBuffer
extends Asn1MessageBuffer

This is the base class to specific decode buffer classes for the different types of encoding rules (BER, DER and PER).

Field Summary

Fields

Modifier and Type	Field and Description
protected int	mByteCount

Fields inherited from class com.objsys.asn1j.runtime.Asn1MessageBufferBase

context, mTypeCode

Method Summary

Modifier and Type	Method and Description
void	addCaptureBuffer(java.io.ByteArrayOutputStream buffer) This method is used to add a capture buffer to the internal capture buffer list.
void	capture(int nbytes) This method captures bytes from the input stream to a separate object for later analysis.
long	decodeIntValue(int length, boolean signExtend) This method decodes the contents of an ASN.1 integer value.
int[]	decodeOIDContents(int llen) This method decodes the contents of an ASN.1 object identifier value.
int[]	decodeRelOIDContents(int llen) This method decodes the contents of an ASN.1 relative object identifier value.
int	getByteCount() This method returns the count of bytes currently read from the message being decoded.
java.io.InputStream	getInputStream() This method returns a reference to the current current decode input stream object.
boolean	getLazyOpenTypeDecode() Return true if lazy open type decoding is on.
void	hexDump() This method provides a hex dump of the bytes in the message being decoded.
protected void	init() This method initializes the input stream for decoding.
void	mark(int readLimit) This method is used to mark the current position in the input stream for retry processing.
int	read() The read method reads a single byte from the current input stream and returns it to the caller.
void	read(byte[] buffer) This version of the read method reads the number of bytes equal to the length of the given input buffer.
void	read(byte[] buffer, int offset, int nbytes) This version of the read method reads the given number of bytes from the current input stream and writes them to the specified byte array at the given offset.
int	read2Bytes() Read the next two bytes from the current input stream into an int, and return that int.
int	read4Bytes() Read the next four bytes from the current input stream into an int, and return that int.
abstract int	readByte() This abstract method returns the next available 8-bit value from the input stream.
void	removeCaptureBuffer(java.io.ByteArrayOutputStream buffer) This method is used to remove a capture buffer from the internal capture buffer list.
void	reset() This method is used to reset the current position in the input stream back to the location of the last 'mark' call.
void	setInputStream(byte[] msgdata, int offset, int length) This method will set the input stream from which data is read.
void	setLazyOpenTypeDecode(boolean value) This method turns lazy open type decoding on or off.
long	skip(long nbytes) This method will skip over the requested number of bytes in the input stream.

Methods inherited from class com.objsys.asn1j.runtime.Asn1MessageBuffer

addNamedEventHandler, getEventHandlerListCount, hasEventHandlers, invokeCharacters, invokeEndElement, invokeStartElement, setEventHandlerList

Methods inherited from class com.objsys.asn1j.runtime.Asn1MessageBufferBase

getContext, hexDump, hexDump, setKey, setTypeCode

Methods inherited from class java.lang.Object

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

Field Detail

mByteCount

protected int mByteCount

Method Detail

capture

public void capture(int nbytes)
             throws Asn1EndOfBufferException,
                    java.io.IOException

This method captures bytes from the input stream to a separate object for later analysis.

Parameters:

nbytes - Number of bytes to capture

Throws:

Asn1EndOfBufferException

java.io.IOException

decodeIntValue

public long decodeIntValue(int length,
                           boolean signExtend)
                    throws Asn1Exception,
                           java.io.IOException

This method decodes the contents of an ASN.1 integer value. It can be used for either BER or PER decoding.

Parameters:

length - Length of encoded contents

signExtend - Sign-extend the decoded value to form a 2's comp result

Returns:

Decoded long integer value

Throws:

Asn1Exception

java.io.IOException

decodeOIDContents

public int[] decodeOIDContents(int llen)
                        throws Asn1Exception,
                               java.io.IOException

This method decodes the contents of an ASN.1 object identifier value. It can be used for either BER or PER decoding.

Parameters:

llen - Length of encoded contents

Returns:

Decoded object identifier value

Throws:

Asn1Exception

java.io.IOException

decodeRelOIDContents

public int[] decodeRelOIDContents(int llen)
                           throws Asn1Exception,
                                  java.io.IOException

This method decodes the contents of an ASN.1 relative object identifier value. It can be used for either BER or PER decoding.

Parameters:

llen - Length of encoded contents

Returns:

Decoded object identifier value

Throws:

Asn1Exception

java.io.IOException

addCaptureBuffer

public void addCaptureBuffer(java.io.ByteArrayOutputStream buffer)

This method is used to add a capture buffer to the internal capture buffer list. A capture buffer is used to capture all bytes read from this position forward from the input stream.

Parameters:

buffer - Buffer into which captured bytes are to be stored

removeCaptureBuffer

public void removeCaptureBuffer(java.io.ByteArrayOutputStream buffer)

This method is used to remove a capture buffer from the internal capture buffer list. The add and remove methods can be used to get a set of raw bytes from the input stream for further processing.

Parameters:

buffer - Buffer in which captured bytes stored

getByteCount

public int getByteCount()

This method returns the count of bytes currently read from the message being decoded.

Returns:

Count of bytes read from input stream

getInputStream

public java.io.InputStream getInputStream()

This method returns a reference to the current current decode input stream object.

Specified by:

getInputStream in class Asn1MessageBuffer

Returns:

New input stream object containing encoded message

getLazyOpenTypeDecode

public boolean getLazyOpenTypeDecode()

Return true if lazy open type decoding is on.

Returns:

true if lazy open type decoding is on

hexDump

public void hexDump()

This method provides a hex dump of the bytes in the message being decoded.

init

protected void init()

This method initializes the input stream for decoding.

mark

public void mark(int readLimit)

This method is used to mark the current position in the input stream for retry processing. It is equivalent to the Java InputStream 'mark' method.

Parameters:

readLimit - Max number of bytes that can be read before mark becomes invalid.

read2Bytes

public final int read2Bytes()
                     throws Asn1EndOfBufferException,
                            java.io.IOException

Read the next two bytes from the current input stream into an int, and return that int. The bytes of the int, from lowest to highest, will correspond to the bytes read from the stream, from last to first. The highest two bytes will be 0. Each byte read will be written to all registered capture buffers.

Returns:

an int representing the 2 bytes read, as described above.

Throws:

Asn1EndOfBufferException - if at end-of-stream

java.io.IOException - Java I/O error

read4Bytes

public final int read4Bytes()
                     throws Asn1EndOfBufferException,
                            java.io.IOException

Read the next four bytes from the current input stream into an int, and return that int. The bytes of the int, from lowest to highest, will correspond to the bytes read from the stream, from last to first. Each byte read will be written to all registered capture buffers.

Returns:

an int representing the 4 bytes read, as described above.

Throws:

Asn1EndOfBufferException - if at end-of-stream

java.io.IOException - Java I/O error

read

public final int read()
               throws Asn1EndOfBufferException,
                      java.io.IOException

The read method reads a single byte from the current input stream and returns it to the caller. It will also write the byte out to all registered capture buffers.

Returns:

byte that was read from the input stream

Throws:

Asn1EndOfBufferException - if at end-of-stream

java.io.IOException - Java I/O error

readByte

public abstract int readByte()
                      throws Asn1Exception,
                             java.io.IOException

This abstract 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

Throws:

Asn1Exception

java.io.IOException

read

public final void read(byte[] buffer,
                       int offset,
                       int nbytes)
                throws Asn1EndOfBufferException,
                       java.io.IOException

This version of the read method reads the given number of bytes from the current input stream and writes them to the specified byte array at the given offset. It also writes the data to all registered capture buffers.

Parameters:

buffer - the buffer into which the data is read

offset - the start offset of the data

nbytes - number of bytes to read

Throws:

Asn1EndOfBufferException - if at end-of-stream

java.io.IOException - Java I/O error

read

public void read(byte[] buffer)
          throws Asn1EndOfBufferException,
                 java.io.IOException

This version of the read method reads the number of bytes equal to the length of the given input buffer.

Parameters:

buffer - the buffer into which the data is read

Throws:

Asn1EndOfBufferException - if at end-of-stream

java.io.IOException - Java I/O error

reset

public void reset()

This method is used to reset the current position in the input stream back to the location of the last 'mark' call. It is equivalent to the Java InputStream 'reset' method.

setLazyOpenTypeDecode

public void setLazyOpenTypeDecode(boolean value)

This method turns lazy open type decoding on or off. Its setting is relevant only when generating table constraint code (otherwise, open types cannot be decoded). Generated decode methods check this setting to determine whether to decode open types or not. When lazy open type decoding is turned on, you can use the generated decodeOpenType* methods to decode open types (again, assuming table constraint code was generated).

setInputStream

public void setInputStream(byte[] msgdata,
                           int offset,
                           int length)

This method will set the input stream from which data is read. This version of the method allows a byte array containing encoded data to be specified.

Parameters:

msgdata - Byte array containing encoded message data

offset - Starting offset of data in the byte array

length - Length (in bytes) of the encoded data

skip

public long skip(long nbytes)
          throws java.io.IOException

This method will skip over the requested number of bytes in the input stream.

Parameters:

nbytes - Number of bytes to skip

Throws:

java.io.IOException