freenet.support.compress

Class Bzip2Compressor

java.lang.Object

freenet.support.compress.Bzip2Compressor

All Implemented Interfaces:

Compressor

public class Bzip2Compressor
extends java.lang.Object

Compressor for BZip2 streams. Due to historical reasons (we used to use the ant-tools bz2 libraries, rather than commons-compress) the compressed streams **DO NOT** have the standard "BZ" header.

Nested Class Summary

Nested classes/interfaces inherited from interface freenet.support.compress.Compressor

Compressor.COMPRESSOR_TYPE

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	BZ_HEADER

Fields inherited from interface freenet.support.compress.Compressor

DEFAULT_COMPRESSORDESCRIPTOR

Constructor Summary

Constructors

Constructor and Description
Bzip2Compressor()

Method Summary

Modifier and Type	Method and Description
Bucket	compress(Bucket data, BucketFactory bf, long maxReadLength, long maxWriteLength) Compress the data.
long	compress(java.io.InputStream input, java.io.OutputStream output, long maxReadLength, long maxWriteLength) Compress the data.
long	compress(java.io.InputStream is, java.io.OutputStream os, long maxReadLength, long maxWriteLength, long amountOfDataToCheckCompressionRatio, int minimumCompressionPercentage) Compress the data (@see Compressor.compress(InputStream, OutputStream, long, long)) with checking of compression effect.
int	decompress(byte[] dbuf, int i, int j, byte[] output) Decompress in RAM only.
long	decompress(java.io.InputStream is, java.io.OutputStream os, long maxLength, long maxCheckSizeBytes) Decompress data.

Methods inherited from class java.lang.Object

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

Field Detail

BZ_HEADER

public static final byte[] BZ_HEADER

Constructor Detail

Bzip2Compressor

public Bzip2Compressor()

Method Detail

compress

public Bucket compress(Bucket data,
                       BucketFactory bf,
                       long maxReadLength,
                       long maxWriteLength)
                throws java.io.IOException,
                       CompressionOutputSizeException

Description copied from interface: Compressor

Compress the data.

Parameters:

data - The bucket to read from.

bf - The means to create a new bucket.

maxReadLength - The maximum number of bytes to read from the input bucket.

maxWriteLength - The maximum number of bytes to write to the output bucket. If this is exceeded, throw a CompressionOutputSizeException.

Returns:

The compressed data.

Throws:

java.io.IOException - If an error occurs reading or writing data.

CompressionOutputSizeException - If the compressed data is larger than maxWriteLength.

compress

public long compress(java.io.InputStream is,
                     java.io.OutputStream os,
                     long maxReadLength,
                     long maxWriteLength,
                     long amountOfDataToCheckCompressionRatio,
                     int minimumCompressionPercentage)
              throws java.io.IOException,
                     CompressionRatioException

Description copied from interface: Compressor

Compress the data (@see Compressor.compress(InputStream, OutputStream, long, long)) with checking of compression effect.

amountOfDataToCheckCompressionRatio - The data amount after compression of which we will check whether we have got the desired effect.

minimumCompressionPercentage - The minimal desired compression effect, %. A value of 0 means that the compression effect will not be checked.

Throws:

CompressionRatioException - If the desired compression effect is not achieved.

java.io.IOException

decompress

public long decompress(java.io.InputStream is,
                       java.io.OutputStream os,
                       long maxLength,
                       long maxCheckSizeBytes)
                throws java.io.IOException,
                       CompressionOutputSizeException

Description copied from interface: Compressor

Decompress data.

Parameters:

is - Where to read the data to decompress from

os - Where to write the final product to

maxLength - The maximum length to decompress (we throw if more is present).

maxCheckSizeBytes - If the data is too big, and this is >0, read up to this many bytes in order to try to get the data size.

Returns:

Number of bytes copied

Throws:

java.io.IOException

CompressionOutputSizeException

decompress

public int decompress(byte[] dbuf,
                      int i,
                      int j,
                      byte[] output)
               throws CompressionOutputSizeException

Description copied from interface: Compressor

Decompress in RAM only.

Parameters:

dbuf - Input buffer.

i - Offset to start reading from.

j - Number of bytes to read.

output - Output buffer.

Throws:

CompressionOutputSizeException

compress

public long compress(java.io.InputStream input,
                     java.io.OutputStream output,
                     long maxReadLength,
                     long maxWriteLength)
              throws java.io.IOException

Description copied from interface: Compressor

Compress the data.

Specified by:

compress in interface Compressor

Parameters:

input - The InputStream to read from.

output - The OutputStream to write to.

maxReadLength - The maximum number of bytes to read from the input bucket.

maxWriteLength - The maximum number of bytes to write to the output bucket. If this is exceeded, throw a CompressionOutputSizeException.

Returns:

The compressed data.

Throws:

java.io.IOException - If an error occurs reading or writing data.

CompressionOutputSizeException - If the compressed data is larger than maxWriteLength.