org.apache.commons.compress.compressors.lz77support

Class Parameters

java.lang.Object

org.apache.commons.compress.compressors.lz77support.Parameters

public final class Parameters
extends java.lang.Object

Parameters of the compressor.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Parameters.Builder Builder for Parameters instances.

Field Summary

Fields

Modifier and Type	Field and Description
static int	TRUE_MIN_BACK_REFERENCE_LENGTH The hard-coded absolute minimal length of a back-reference.

Method Summary

Modifier and Type	Method and Description
static Parameters.Builder	builder(int windowSize) Initializes the builder for the compressor's parameters with a minBackReferenceLength of 3 and max*Length equal to windowSize - 1.
boolean	getLazyMatching() Gets whether to perform lazy matching.
int	getLazyMatchingThreshold() Gets the threshold for lazy matching.
int	getMaxBackReferenceLength() Gets the maximal length of a back-reference found.
int	getMaxCandidates() Gets the maximum number of back-reference candidates to consider.
int	getMaxLiteralLength() Gets the maximal length of a literal block.
int	getMaxOffset() Gets the maximal offset of a back-reference found.
int	getMinBackReferenceLength() Gets the minimal length of a back-reference found.
int	getNiceBackReferenceLength() Gets the length of a back-reference that is considered nice enough to stop searching for longer ones.
int	getWindowSize() Gets the size of the sliding window - this determines the maximum offset a back-reference can take.

Methods inherited from class java.lang.Object

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

Field Detail

TRUE_MIN_BACK_REFERENCE_LENGTH

public static final int TRUE_MIN_BACK_REFERENCE_LENGTH

The hard-coded absolute minimal length of a back-reference.

See Also:

Constant Field Values

Method Detail

builder

public static Parameters.Builder builder(int windowSize)

Initializes the builder for the compressor's parameters with a minBackReferenceLength of 3 and max*Length equal to windowSize - 1.

It is recommended to not use this method directly but rather tune a pre-configured builder created by a format specific factory like SnappyCompressorOutputStream.createParameterBuilder(int).

Parameters:

windowSize - the size of the sliding window - this determines the maximum offset a back-reference can take. Must be a power of two.

Returns:

a builder configured for the given window size

Throws:

java.lang.IllegalArgumentException - if windowSize is not a power of two.

getWindowSize

public int getWindowSize()

Gets the size of the sliding window - this determines the maximum offset a back-reference can take.

Returns:

the size of the sliding window

getMinBackReferenceLength

public int getMinBackReferenceLength()

Gets the minimal length of a back-reference found.

Returns:

the minimal length of a back-reference found

getMaxBackReferenceLength

public int getMaxBackReferenceLength()

Gets the maximal length of a back-reference found.

Returns:

the maximal length of a back-reference found

getMaxOffset

public int getMaxOffset()

Gets the maximal offset of a back-reference found.

Returns:

the maximal offset of a back-reference found

getMaxLiteralLength

public int getMaxLiteralLength()

Gets the maximal length of a literal block.

Returns:

the maximal length of a literal block

getNiceBackReferenceLength

public int getNiceBackReferenceLength()

Gets the length of a back-reference that is considered nice enough to stop searching for longer ones.

Returns:

the length of a back-reference that is considered nice enough to stop searching

getMaxCandidates

public int getMaxCandidates()

Gets the maximum number of back-reference candidates to consider.

Returns:

the maximum number of back-reference candidates to consider

getLazyMatching

public boolean getLazyMatching()

Gets whether to perform lazy matching.

Returns:

whether to perform lazy matching

getLazyMatchingThreshold

public int getLazyMatchingThreshold()

Gets the threshold for lazy matching.

Returns:

the threshold for lazy matching