iaik.cms

Class CompressionProvider

java.lang.Object

iaik.asn1.structures.AlgorithmID

iaik.cms.CompressionProvider

All Implemented Interfaces:

ASN1Type

public class CompressionProvider
extends AlgorithmID

This class provides the compression which is provided to the CMS CompressedContent type object. All the relevent compression algorithms are to be provided by this class or its derivations. This class extends The iaik.asn1.structures.AlgorithmID object so that the compression AlgorithmID's can be supplied by this provider. Implementors can choose to compress the supplied data with any type of compression algorithm by the following means:

 1.  Extend the CompressionProvider class, and override method getInputStreamCompressEngine,
 which is specified as follows:
 
  if(algorithmid.equals(CompressionProvider.zlib_compress))
      return new ZLIBCompressionInputStream(inputstream, CompressMode, blocksize);
  else
     throw new NoSuchAlgorithmException("Algorithm " + algorithmid.getAlgorithm().getName() + " not available!");
 
 2.  Specify the AlgorithmID for the compression algorithm being used.  This AlgorithmID
 should be added into the extension of the CompressionProvider as CompressionProvider is
 an extension of AlgorithmID. 
 
 3.  Write a Compression InputStream class which implements interface
 InputStreamCompressEngine and make sure the getInputStream() method is 
 implemented.
 
 4.  The CompressedContent.setCompressionProvider() method can be used to set the CompressionProvider
 which will be used.
 

Field Summary

Fields

Modifier and Type	Field and Description
static AlgorithmID	zlib_compress Creates an AlgorithmID for the ZLIB compression algorithm.

Fields inherited from class iaik.asn1.structures.AlgorithmID

aes_128_CBC, aes_128_ECB, aes_128_wrap, aes_192_CBC, aes_192_ECB, aes_192_wrap, aes_256_CBC, aes_256_ECB, aes_256_wrap, cast3_CBC, cast5_CBC, cms_3DES_wrap, cms_cast_wrap, cms_cast5_wrap, cms_idea_wrap, cms_pwri_kek, cms_rc2_wrap, des_CBC, des_EDE3_CBC, dhKeyAgreement, dhSinglePass_cofactorDH_sha1kdf_scheme, dhSinglePass_stdDH_sha1kdf_scheme, dsa, dsa_With_SHA1, dsaWithSHA, dsaWithSHA1, dsaX957, ecdsa_with_Recommended, ecdsa_with_Sha224, ecdsa_with_Sha256, ecdsa_with_Sha384, ecdsa_with_Sha512, ecdsa_with_Specified, ecdsaWithSHA1, esdh, esdhKeyAgreement, id_ecPublicKey, id_RSASAA_PSS, idea_CBC, implementations, md2, md2WithRSAEncryption, md4, md4WithRSAEncryption, md5, md5WithRSAEncryption, mgf1, pbeWithMD5AndDES_CBC, pbeWithSHAAnd128BitRC2_CBC, pbeWithSHAAnd128BitRC4, pbeWithSHAAnd2_KeyTripleDES_CBC, pbeWithSHAAnd3_KeyTripleDES_CBC, pbeWithSHAAnd40BitRC2_CBC, pbeWithSHAAnd40BitRC4, pbkdf2, rc2_CBC, rc4, rc5_CBC, rsa, rsaEncryption, rsaESOAEP, sha, sha1, sha1WithRSAEncryption, sha224, sha224WithRSAEncryption, sha256, sha256WithRSAEncryption, sha384, sha384WithRSAEncryption, sha512, sha512WithRSAEncryption

Constructor Summary

Constructors

Constructor and Description
CompressionProvider()

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	compress(AlgorithmID algorithmid, byte[] data, int compressionMode) Uses the given compression algorithm to compress/decompress the supplied input data.
InputStreamCompressEngine	getInputStreamCompressEngine(AlgorithmID algorithmid, java.io.InputStream inputstream, int CompressMode, int blocksize) This method returns an InputStreamCompressEngine for compressing or decompressing data read from some input stream.

Methods inherited from class iaik.asn1.structures.AlgorithmID

changeObjectID, changeOIDString, clone, decode, encodeAbsentParametersAsNull, equals, getAlgorithm, getAlgorithmParameters, getAlgorithmParameters, getAlgorithmParameters, getCipherInstance, getCipherInstance, getDecodedAbsentParameters, getImplementationName, getInstance, getInstance, getKeyAgreementInstance, getKeyAgreementInstance, getKeyFactoryInstance, getKeyFactoryInstance, getKeyGeneratorInstance, getKeyGeneratorInstance, getKeyPairGeneratorInstance, getKeyPairGeneratorInstance, getMessageDigestInstance, getMessageDigestInstance, getName, getParameter, getRawImplementationName, getSecretKeyFactoryInstance, getSecretKeyFactoryInstance, getSignatureInstance, getSignatureInstance, initSignatureSign, initSignatureVerify, setAlgorithmParameters, setParameter, toASN1Object, toASN1Object, toEntrustAlgorithmID, toString

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

zlib_compress

public static AlgorithmID zlib_compress

Creates an AlgorithmID for the ZLIB compression algorithm.

Constructor Detail

CompressionProvider

public CompressionProvider()

Method Detail

getInputStreamCompressEngine

public InputStreamCompressEngine getInputStreamCompressEngine(AlgorithmID algorithmid,
                                                     java.io.InputStream inputstream,
                                                     int CompressMode,
                                                     int blocksize)
                                                       throws java.security.NoSuchAlgorithmException

This method returns an InputStreamCompressEngine for compressing or decompressing data read from some input stream. An InputStreamCompressEngine is used by class CompressedDataStream for content compression or decompression.

Parameters:

algorithmid - the compression/decompression algorithm to be used

inputstream - the input stream supplying the data to be compressed/decompressed

CompressMode - the compression mode to be used (COMPRESS or DECOMPRESS)

blocksize - the size of the internal buffer, if used by the compress engine.

Returns:

the InputStreamCompressEngine just created

Throws:

java.security.NoSuchAlgorithmException

compress

public byte[] compress(AlgorithmID algorithmid,
              byte[] data,
              int compressionMode)
                throws java.io.IOException,
                       java.security.NoSuchAlgorithmException

Uses the given compression algorithm to compress/decompress the supplied input data. This class provides an implementation of the ZLIB compression algorithm ([RFC1950] [RFC1951]) based on the Deflater/Inflater utilities of the java.utils.zip package.

Parameters:

algorithmid - the compression/decompression algorithm to be used

data - the input data to be compressed/decompressed

compressionMode - the compression mode to be used (COMPRESS or DECOMPRESS)

Returns:

the compressed/decompressed data as byte array

Throws:

IOExecption - if an I/O error occurs during data compression/decompression

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

java.io.IOException