iaik.cms

Class CompressedDataStream

java.lang.Object

iaik.cms.CompressedDataStream

All Implemented Interfaces:

ContentStream

Direct Known Subclasses:

CompressedData, SMimeCompressed

public class CompressedDataStream
extends java.lang.Object
implements ContentStream

This class represents the stream supporting implementation of the CMS CompressedData type. The compressed-data content type is identified by the following object identifier:

 
  
    id-ct-compressedData OBJECT IDENTIFIER ::= { iso(1) member-body(2)
          us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) ct(1) 9 }
   
  
 

which refers to the OID "1.2.840.113549.1.9.16.1.9".

The CompressedData type provides a means for compressing or decompressing the content of a CMS message. The algorithm identifier identifies the compression algorithm to be used. The ZLIB compression algorithm is used as the default algorithm for compressing the EncapsulatedContent(as defined by RFC 3274). ZLIB compression is defined in RFC1950 and RFC 1951.

 
   
     CompressedData ::= SEQUENCE {
        version CMSVersion,
        compressionAlgorithm CompressionAlgorithmIdentifier,
        encapContentInfo EncapsulatedContentInfo
     }
   
  
 

Field Summary

Fields

Modifier and Type	Field and Description
static ObjectID	contentType The object identifier which specifies the CMS compressed data, see RFC 3274
static int	DEFAULT_BLOCKSIZE The Default blocksize set to 2048 bytes
static int	EXPLICIT Used to determine if data is explicitly compressed
static int	IMPLICIT Used to determine if data is implicitly compressed
protected int	m_blockSize The user defined blocksize
protected AlgorithmID	m_compressionAlgorithm The compression algorithm ID
protected ObjectID	m_encapContentType The encapulsted content type
protected java.io.InputStream	m_inputStream The input stream used to compress data
protected int	m_version The SMIME version, should be 0

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CompressedDataStream() Default constructor for dynamic object creation in ContentInfoStream.
	CompressedDataStream(java.io.InputStream inputstream) Creates a new CompressedDataStream where the BER encoded data is read from the given InputStream.
	CompressedDataStream(java.io.InputStream inputstream, AlgorithmID algorithmid, int mode) Creates a new CMS CompressedDataStream object where the content to be compressed is read from the supplied InputStream.
	CompressedDataStream(ObjectID objectid, java.io.InputStream inputstream, AlgorithmID algorithmid, int mode) Creates a new CompressedDataStream object for the given content data.

Method Summary

Methods

Modifier and Type	Method and Description
void	decode(java.io.InputStream inputstream) Reads and decodes an encoded CompressedDataStream from an input stream.
int	getBlockSize() Gets the block size defining the length of each definite primitive encoded octet string component.
AlgorithmID	getCompressionAlgorithm() Returns the compression algorithm
CompressionProvider	getCompressionProvider() Returns the CompressionProvider
ObjectID	getContentType() Returns the content type this class implements.
EncapsulatedContentInfoStream	getEncapsulatedContentInfoStream() Returns the EncapsulatedContentInfoStream.
ObjectID	getEncapsulatedContentType() Returns the content type the EncapsulatetContentInfo represents.
java.io.InputStream	getInputStream() Returns an InputStream from where the compressed data can be read.
int	getMode() Returns the mode of this CompressedData.
int	getVersion() Returns the version of SMime compresssion being used (0)
void	setBlockSize(int blocksize) Sets the block size for defining the length of each definite primitive encoded octet string component.
void	setCompressionProvider(CompressionProvider compressionprovider) Sets the CompressionProvider for this CompressedDataStream.
void	setInputStream(java.io.InputStream inputstream) Sets the content supplying input stream.
ASN1Object	toASN1Object() Returns this CMS CompressedDataStream as an ASN1Object.
protected ASN1Object	toASN1Object(int blocksize) Returns this CMS CompressedData as ASN1Object.
java.lang.String	toString() Returns a string giving some information about this CompressedDataStream object.
java.lang.String	toString(boolean detailed) Returns a string giving some - if requested - detailed information about this CompressedDataStream object.
void	writeTo(java.io.OutputStream outputstream) BER encodes and writes this CompressedData to the supplied output stream.
void	writeTo(java.io.OutputStream outputstream, int blocksize) Writes this CompressedData encoded to the supplied output stream.

Methods inherited from class java.lang.Object

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

Field Detail

m_inputStream

protected java.io.InputStream m_inputStream

The input stream used to compress data

m_blockSize

protected int m_blockSize

The user defined blocksize

m_encapContentType

protected ObjectID m_encapContentType

The encapulsted content type

m_compressionAlgorithm

protected AlgorithmID m_compressionAlgorithm

The compression algorithm ID

m_version

protected int m_version

The SMIME version, should be 0

DEFAULT_BLOCKSIZE

public static final int DEFAULT_BLOCKSIZE

The Default blocksize set to 2048 bytes

See Also:

Constant Field Values

EXPLICIT

public static final int EXPLICIT

Used to determine if data is explicitly compressed

See Also:

Constant Field Values

IMPLICIT

public static final int IMPLICIT

Used to determine if data is implicitly compressed

See Also:

Constant Field Values

contentType

public static final ObjectID contentType

The object identifier which specifies the CMS compressed data, see RFC 3274

Constructor Detail

CompressedDataStream

public CompressedDataStream(java.io.InputStream inputstream,
                    AlgorithmID algorithmid,
                    int mode)

Creates a new CMS CompressedDataStream object where the content to be compressed is read from the supplied InputStream. The mode parameter specifies whether to include the compressed data (mode = CompressedDataStream.IMPLICIT) or not include it (mode = CompressedDataStream.EXPLICIT). The content type of the inherent EncapsulatedContentInfo automatically is set to CMS Data.

Parameters:

inputstream - the InputStream containing the data to encrypt

algorithmid - algorithm used to compress the data

mode - either CompressedDataStream.IMPLICIT for including the compressed data, or CompressedDataStream.EXPLICIT for not including it

CompressedDataStream

public CompressedDataStream(java.io.InputStream inputstream)
                     throws CMSParsingException,
                            java.io.IOException

Creates a new CompressedDataStream where the BER encoded data is read from the given InputStream.

Parameters:

inputstream - the InputStream holding a BER encoded EncryptedDataStream object

Throws:

java.io.IOException - if an I/O error occurs during reading from the InputStream

CMSParsingException - if an error occurs while parsing the object

CompressedDataStream

public CompressedDataStream(ObjectID objectid,
                    java.io.InputStream inputstream,
                    AlgorithmID algorithmid,
                    int mode)

Creates a new CompressedDataStream object for the given content data. The data to be compressed is supplied from an input stream. The mode parameter specifies whether to include the compressed data (mode = CompressedDataStream.IMPLICIT) or not include it (mode = CompressedDataStream.EXPLICIT).

Parameters:

objectid - the content type (e.g. ObjectID.cms_data) of the data to be compressed

inputstream - the data to be compressed, supplied from an input stream

algorithmid - the compression algorithm to be used for content compression

mode - either CompressedDataStream.IMPLICIT for including the compressed data, or CompressedDataStream.EXPLICIT for not including it

CompressedDataStream

protected CompressedDataStream()

Default constructor for dynamic object creation in ContentInfoStream.

Method Detail

writeTo

public void writeTo(java.io.OutputStream outputstream,
           int blocksize)
             throws java.io.IOException

Writes this CompressedData encoded to the supplied output stream. If block size has a value > 0, in implicit mode the inherent compressed data is encoded as constructed OCTET STRING. In this case the encoding is splitted according to the defined block size:

 
  
   * 0x24 0x80
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
           0x04 <blocksize> <data>
                ...
    0x00 0x00
   
  
 

If the block size is not positive, the whole data is encoded as one single primitive definie octet string:

 
  
   0x04 <length> <data>
   
  
 

Parameters:

outputstream - the output stream to which this SignedData shall be written

blocksize - the block size defining the encoding scheme - and specifying the length of each primitive encoded octet string component, if positive

Throws:

java.io.IOException - if an error occurs during writing the object

writeTo

public void writeTo(java.io.OutputStream outputstream)
             throws java.io.IOException

BER encodes and writes this CompressedData to the supplied output stream.

Parameters:

outputstream - the output stream to which this EnvelopedData shall be written

Throws:

java.io.IOException

toString

public java.lang.String toString(boolean detailed)

Returns a string giving some - if requested - detailed information about this CompressedDataStream object.

Specified by:

toString in interface ContentStream

Parameters:

detailed - - whether or not to give detailed information

Returns:

the string representation

toString

public java.lang.String toString()

Returns a string giving some information about this CompressedDataStream object.

Overrides:

toString in class java.lang.Object

Returns:

the string representation

toASN1Object

protected ASN1Object toASN1Object(int blocksize)
                           throws CMSException

Returns this CMS CompressedData as ASN1Object.

Note: If AlgorithmID parameters are not set, this method will encode the AlgorithmIdentifier with only the algorithm ObjectID (as per RFC 3274 section 2.1 recommendations).

For Example:

Without Algorithm Parameters, AlgorithmIdentifier will be encoded as follows:

 
  
   AlgorithmIdentifier  ::=  SEQUENCE  {
        algorithm               OBJECT IDENTIFIER }
   
  
 

With Algorithm Parameters, AlgorithmIdentifier will be encoded as follows:

 
  
   AlgorithmIdentifier  ::=  SEQUENCE  {
        algorithm               OBJECT IDENTIFIER,
        parameters              ANY DEFINED BY algorithm  }
   
  
 

Parameters:

blocksize - the block size defining the encoding scheme - and specifying the length of each primitive encoded octet string component, if positive

Returns:

this CompressedData as ASN1Object

Throws:

CMSException - if the ASN1Object could not be created

toASN1Object

public ASN1Object toASN1Object()
                        throws CMSException

Returns this CMS CompressedDataStream as an ASN1Object.

Specified by:

toASN1Object in interface ContentStream

Returns:

this CompressedData as ASN1Object.

Throws:

CMSException - if the ASN1Object could not be created

setCompressionProvider

public void setCompressionProvider(CompressionProvider compressionprovider)

Sets the CompressionProvider for this CompressedDataStream. This method allows to explicitly set a CompressionProvider for this CompressedDataStream. If no explicit CompressionProvider is set, the default CompressionProvider will be used for the required cryptographic operations.

This class may use the following method of the CompressionProvider, which may be overriden by an application, if required:

getInputStreamCompressEngine() to get an InputStreamCompressEngine through which the data is to be piped for data compression/decompression

Parameters:

compressionprovider - the CompressionProvider

getCompressionProvider

public CompressionProvider getCompressionProvider()

Returns the CompressionProvider

Returns:

CompressionProvider

setInputStream

public void setInputStream(java.io.InputStream inputstream)
                    throws java.io.IOException,
                           java.security.NoSuchAlgorithmException

Sets the content supplying input stream. When having created a new CompressedDataStream object to be encoded to a stream, this method may be used to supply the content to be compressed. When having decoded and parsed a received CompressedDataStream object coming from some stream, this method may be used for supplying the compressed content transmitted by other means.

Parameters:

inputstream - an input stream supplying the content to be compressed/decompressed

Throws:

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

java.security.NoSuchAlgorithmException - - if the compression algorithm is not supported

setBlockSize

public void setBlockSize(int blocksize)

Sets the block size for defining the length of each definite primitive encoded octet string component. If the value of blockSize is smaller or equal to zero the whole data is encoded as definite primitive octet string.

Specified by:

setBlockSize in interface ContentStream

Parameters:

blocksize - for defining the encoding scheme and setting the octet string component length, if positive

getVersion

public int getVersion()

Returns the version of SMime compresssion being used (0)

Returns:

version of SMime Compression (0)

getMode

public int getMode()

Returns the mode of this CompressedData.

Returns:

IMPLICIT (1) or EXPLICIT (2)

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException,
                                          java.security.NoSuchAlgorithmException

Returns an InputStream from where the compressed data can be read. Attention! The stream only may be read once.

When having created a new CompressedDataStream object to be encoded to a stream, this method should only be called in EXPLICT mode to get and read away the compressed content to be transmitted by other means. In IMPLICT mode this method shall not be called at all since the compressed content has to be included in the CompressedData message (and therefore should not be read "away"). When having decoded and parsed a received CompressedDataStream object coming from some stream, this method may be used for obtaining the raw (decompressed) content.

Returns:

an InputStream for reading the decrypted data

Throws:

java.io.IOException

java.security.NoSuchAlgorithmException

getEncapsulatedContentType

public ObjectID getEncapsulatedContentType()

Returns the content type the EncapsulatetContentInfo represents.

getEncapsulatedContentInfoStream

public EncapsulatedContentInfoStream getEncapsulatedContentInfoStream()

Returns the EncapsulatedContentInfoStream.

getContentType

public ObjectID getContentType()

Returns the content type this class implements.

Specified by:

getContentType in interface ContentStream

Returns:

ObjectID.cms_compressedData ("1.2..840.113549.1.9.16.1.9")

getCompressionAlgorithm

public AlgorithmID getCompressionAlgorithm()

Returns the compression algorithm

getBlockSize

public int getBlockSize()

Gets the block size defining the length of each definite primitive encoded octet string component. If the value of blockSize is smaller or equal to zero the whole data is encoded as definite primitive octet string.

Specified by:

getBlockSize in interface ContentStream

Returns:

blockSize defining the encoding scheme and setting the octet string component length, if positive

decode

public void decode(java.io.InputStream inputstream)
            throws CMSParsingException,
                   java.io.IOException

Reads and decodes an encoded CompressedDataStream from an input stream.

Specified by:

decode in interface ContentStream

Parameters:

inputstream - the InputStream supplying an encoded CompressedData object

Throws:

java.io.IOException - if an I/O error occurs during reading from the InputStream

CMSParsingException - if an error occurs while parsing the object