Class Parameters
java.lang.Object
org.apache.commons.compress.compressors.lz77support.Parameters
Parameters of the
compressor
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Nested Class Summary
Nested Classes -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final boolean
private final int
private final int
private final int
private final int
private final int
private final int
private final int
static final int
The hard-coded absolute minimal length of a back-reference.private final int
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Constructor Summary
ConstructorsModifierConstructorDescriptionprivate
Parameters
(int windowSize, int minBackReferenceLength, int maxBackReferenceLength, int maxOffset, int maxLiteralLength, int niceBackReferenceLength, int maxCandidates, boolean lazyMatching, int lazyThreshold) -
Method Summary
Modifier and TypeMethodDescriptionstatic Parameters.Builder
builder
(int windowSize) Initializes the builder for the compressor's parameters with aminBackReferenceLength
of 3 andmax*Length
equal towindowSize - 1
.boolean
Gets whether to perform lazy matching.int
Gets the threshold for lazy matching.int
Gets the maximal length of a back-reference found.int
Gets the maximum number of back-reference candidates to consider.int
Gets the maximal length of a literal block.int
Gets the maximal offset of a back-reference found.int
Gets the minimal length of a back-reference found.int
Gets the length of a back-reference that is considered nice enough to stop searching for longer ones.int
Gets the size of the sliding window - this determines the maximum offset a back-reference can take.private static boolean
isPowerOfTwo
(int x)
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Field Details
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TRUE_MIN_BACK_REFERENCE_LENGTH
public static final int TRUE_MIN_BACK_REFERENCE_LENGTHThe hard-coded absolute minimal length of a back-reference.- See Also:
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windowSize
private final int windowSize -
minBackReferenceLength
private final int minBackReferenceLength -
maxBackReferenceLength
private final int maxBackReferenceLength -
maxOffset
private final int maxOffset -
maxLiteralLength
private final int maxLiteralLength -
niceBackReferenceLength
private final int niceBackReferenceLength -
maxCandidates
private final int maxCandidates -
lazyThreshold
private final int lazyThreshold -
lazyMatching
private final boolean lazyMatching
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Constructor Details
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Parameters
private Parameters(int windowSize, int minBackReferenceLength, int maxBackReferenceLength, int maxOffset, int maxLiteralLength, int niceBackReferenceLength, int maxCandidates, boolean lazyMatching, int lazyThreshold)
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Method Details
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builder
Initializes the builder for the compressor's parameters with aminBackReferenceLength
of 3 andmax*Length
equal towindowSize - 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:
IllegalArgumentException
- if windowSize is not a power of two.
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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
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getMinBackReferenceLength
public int getMinBackReferenceLength()Gets the minimal length of a back-reference found.- Returns:
- the minimal length of a back-reference found
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getMaxBackReferenceLength
public int getMaxBackReferenceLength()Gets the maximal length of a back-reference found.- Returns:
- the maximal length of a back-reference found
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getMaxOffset
public int getMaxOffset()Gets the maximal offset of a back-reference found.- Returns:
- the maximal offset of a back-reference found
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getMaxLiteralLength
public int getMaxLiteralLength()Gets the maximal length of a literal block.- Returns:
- the maximal length of a literal block
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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
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getMaxCandidates
public int getMaxCandidates()Gets the maximum number of back-reference candidates to consider.- Returns:
- the maximum number of back-reference candidates to consider
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getLazyMatching
public boolean getLazyMatching()Gets whether to perform lazy matching.- Returns:
- whether to perform lazy matching
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getLazyMatchingThreshold
public int getLazyMatchingThreshold()Gets the threshold for lazy matching.- Returns:
- the threshold for lazy matching
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isPowerOfTwo
private static boolean isPowerOfTwo(int x)
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