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Bouncy Castle Cryptography Library 1.64 | |||||||||
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java.lang.Objectorg.bouncycastle.openpgp.PGPCompressedDataGenerator
Generator for producing compressed data packets.
A PGPCompressedDataGenerator is used by invoking one of the open functions to create an OutputStream that raw data can be supplied to for compression:
If the data needs to written out in blocks, useopen(OutputStream, byte[])
to create a
packet consisting of a series of compressed data objects (partials).
A PGPCompressedDataGenerator is usually used to wrap the OutputStream
obtained
from a
PGPEncryptedDataGenerator
(i.e. to compress data prior to encrypting it).
Raw data is not typically written directly to the OutputStream obtained from a
PGPCompressedDataGenerator. The OutputStream is usually wrapped by a
PGPLiteralDataGenerator
, which encodes the raw data prior to compression.
Once data for compression has been written to the constructed OutputStream, writing of the object
stream is completed by closing the OutputStream obtained from the #open() method, or
equivalently invoking close()
on this generator.
Field Summary |
Fields inherited from interface org.bouncycastle.bcpg.CompressionAlgorithmTags |
BZIP2, UNCOMPRESSED, ZIP, ZLIB |
Constructor Summary | |
PGPCompressedDataGenerator(int algorithm)
Construct a new compressed data generator. |
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PGPCompressedDataGenerator(int algorithm,
int compression)
Construct a new compressed data generator. |
Method Summary | |
void |
close()
Close the compressed object - this is equivalent to calling close on the stream returned by the open() method. |
java.io.OutputStream |
open(java.io.OutputStream out)
Return an OutputStream which will save the data being written to the compressed object. |
java.io.OutputStream |
open(java.io.OutputStream out,
byte[] buffer)
Return an OutputStream which will compress the data as it is written to it. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public PGPCompressedDataGenerator(int algorithm)
algorithm
- the identifier of the compression algorithm
to use.public PGPCompressedDataGenerator(int algorithm, int compression)
algorithm
- the identifier of the compression algorithm
to use.compression
- the Deflater
compression level to use.Method Detail |
public java.io.OutputStream open(java.io.OutputStream out) throws java.io.IOException
The stream created can be closed off by either calling close() on the stream or close() on the generator. Closing the returned stream does not close off the OutputStream parameter out.
out
- underlying OutputStream to be used.
java.io.IOException
java.lang.IllegalStateException
public java.io.OutputStream open(java.io.OutputStream out, byte[] buffer) throws java.io.IOException, PGPException
The stream created can be closed off by either calling close() on the stream or close() on the generator. Closing the returned stream does not close off the OutputStream parameter out.
Note: if the buffer is not a power of 2 in length only the largest power of 2 bytes worth of the buffer will be used.
Note: using this may break compatibility with RFC 1991 compliant tools. Only recent OpenPGP implementations are capable of accepting these streams.
out
- the stream to write compressed packets to.buffer
- a buffer to use to buffer and write partial packets. The returned stream takes
ownership of the buffer and will use it to buffer plaintext data for compression.
java.io.IOException
- if an error occurs writing stream header information to the provider
output stream.
PGPException
java.lang.IllegalStateException
- if this generator already has an open OutputStream.public void close() throws java.io.IOException
close
in interface org.bouncycastle.openpgp.StreamGenerator
java.io.IOException
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Bouncy Castle Cryptography Library 1.64 | |||||||||
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