XZ for Java 1.9 · org.tukaani.xz.lz.LZEncoder

Modifier and Type	Field and Description
pack-priv final byte[]	buf
pack-priv final int	bufSize
private boolean	finishing
private final int	keepSizeAfter Number of bytes that must be available, the current byte included, to make hasEnoughData return true.
private final int	keepSizeBefore Number of bytes to keep available before the current byte when moving the LZ window.
pack-priv final int	matchLenMax
public static final int	MF_BT4
public static final int	MF_HC4
pack-priv final int	niceLen
private int	pendingSize
private int	readLimit
pack-priv int	readPos
private int	writePos

Access	Constructor and Description
pack-priv	LZEncoder(int dictSize, int extraSizeBefore, int extraSizeAfter, int niceLen, int matchLenMax, ArrayCache arrayCache) Creates a new LZEncoder.

Method Summary

Modifier and Type	Method and Description
public void	copyUncompressed(OutputStream out, int backward, int len)
public int	fillWindow(byte[] in, int off, int len) Copies new data into the LZEncoder's buffer.
public int	getAvail() Get the number of bytes available, including the current byte.
private static int	getBufSize(int dictSize, int extraSizeBefore, int extraSizeAfter, int matchLenMax) Gets the size of the LZ window buffer that needs to be allocated.
public int	getByte(int backward) Gets the byte from the given backward offset.
public int	getByte(int forward, int backward) Gets the byte from the given forward minus backward offset.
public static LZEncoder	getInstance(int dictionary size dictSize, int number of bytes to keep available in the history in addition to dictSize extraSizeBefore, int number of bytes that must be available after current position + matchLenMax extraSizeAfter, int if a match of at least `niceLen` bytes is found, be happy with it and don't stop looking for longer matches niceLen, int don't test for matches longer than `matchLenMax` bytes matchLenMax, int match finder ID mf, int match finder search depth limit depthLimit, ArrayCache arrayCache) Creates a new LZEncoder.
public abstract Matches	getMatches() Runs match finder for the next byte and returns the matches found.
public int	Returns: length of the match; it is in the range [0, lenLimit] getMatchLen(int zero-based distance of the match to test dist, int don't test for a match longer than this lenLimit) Get the length of a match at the given distance.
public int	Returns: length of the match; it is in the range [0, lenLimit] getMatchLen(int forward offset forward, int zero-based distance of the match to test dist, int don't test for a match longer than this lenLimit) Get the length of a match at the given distance and forward offset.
public static int	getMemoryUsage(int dictSize, int extraSizeBefore, int extraSizeAfter, int matchLenMax, int mf) Gets approximate memory usage of the LZEncoder base structure and the match finder as kibibytes.
public int	getPos() Gets the lowest four bits of the absolute offset of the current byte.
public boolean	hasEnoughData(int alreadyReadLen) Tests if there is enough input available to let the caller encode at least one more byte.
public boolean	isStarted() Returns true if at least one byte has already been run through the match finder.
pack-priv int	Returns: the number of bytes available or zero if there is not enough input available movePos(int minimum number of available bytes when flushing; encoding may be continued with new input after flushing requiredForFlushing, int minimum number of available bytes when finishing; encoding must not be continued after finishing or the match finder state may be corrupt requiredForFinishing) Moves to the next byte, checks if there is enough input available, and returns the amount of input available.
private void	moveWindow() Moves data from the end of the buffer to the beginning, discarding old data and making space for new input.
pack-priv static void	normalize(int[] positions, int positionsCount, int normalizationOffset)
private void	processPendingBytes() Process pending bytes remaining from preset dictionary initialization or encoder flush operation.
public void	putArraysToCache(ArrayCache arrayCache)
public void	setFinishing() Marks that there is no more input remaining.
public void	setFlushing() Marks that all the input needs to be made available in the encoded output.
public void	setPresetDict(int dictSize, byte[] presetDict) Sets a preset dictionary.
public abstract void	skip(int len) Skips the given number of bytes in the match finder.
public boolean	Returns: true if matches are valid, false if match finder is broken verifyMatches(Matches return value from `getMatches` matches) Verifies that the matches returned by the match finder are valid.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

buf	back to summary
pack-priv final byte[] buf

bufSize	back to summary
pack-priv final int bufSize

finishing	back to summary
private boolean finishing

keepSizeAfter	back to summary
private final int keepSizeAfter Number of bytes that must be available, the current byte included, to make hasEnoughData return true. Flushing and finishing are naturally exceptions to this since there cannot be any data after the end of the uncompressed input.

keepSizeBefore	back to summary
private final int keepSizeBefore Number of bytes to keep available before the current byte when moving the LZ window.

matchLenMax	back to summary
pack-priv final int matchLenMax

MF_BT4	back to summary
public static final int MF_BT4

MF_HC4	back to summary
public static final int MF_HC4

niceLen	back to summary
pack-priv final int niceLen

pendingSize	back to summary
private int pendingSize

readLimit	back to summary
private int readLimit

readPos	back to summary
pack-priv int readPos

writePos	back to summary
private int writePos

LZEncoder	back to summary
pack-priv LZEncoder(int dictSize, int extraSizeBefore, int extraSizeAfter, int niceLen, int matchLenMax, ArrayCache arrayCache) Creates a new LZEncoder. See `getInstance`.

Method Detail

copyUncompressed	back to summary
public void copyUncompressed(OutputStream out, int backward, int len) throws IOException

fillWindow	back to summary
public int fillWindow(byte[] in, int off, int len) Copies new data into the LZEncoder's buffer.

getAvail back to summary

getAvail	back to summary
public int getAvail() Get the number of bytes available, including the current byte. Note that the result is undefined if `getMatches` or `skip` hasn't been called yet and no preset dictionary is being used.

public int getAvail()

Get the number of bytes available, including the current byte.

Note that the result is undefined if getMatches or skip hasn't been called yet and no preset dictionary is being used.

getBufSize	back to summary
private static int getBufSize(int dictSize, int extraSizeBefore, int extraSizeAfter, int matchLenMax) Gets the size of the LZ window buffer that needs to be allocated.

getByte back to summary

getByte	back to summary
public int getByte(int backward) Gets the byte from the given backward offset. The current byte is at `0`, the previous byte at `1` etc. To get a byte at zero-based distance, use `getByte(dist + 1).` `This function is equivalent to getByte(0, backward).`

public int getByte(int backward)

Gets the byte from the given backward offset.

The current byte is at 0, the previous byte at 1 etc. To get a byte at zero-based distance, use getByte(dist + 1).

This function is equivalent to getByte(0, backward).

getByte	back to summary
public int getByte(int forward, int backward) Gets the byte from the given forward minus backward offset. The forward offset is added to the current position. This lets one read bytes ahead of the current byte.

getInstance back to summary

getInstance	back to summary
public static LZEncoder getInstance(int dictSize, int extraSizeBefore, int extraSizeAfter, int niceLen, int matchLenMax, int mf, int depthLimit, ArrayCache arrayCache) Creates a new LZEncoder. Parameters dictSize:int dictionary size extraSizeBefore:int number of bytes to keep available in the history in addition to dictSize extraSizeAfter:int number of bytes that must be available after current position + matchLenMax niceLen:int if a match of at least `niceLen` bytes is found, be happy with it and don't stop looking for longer matches matchLenMax:int don't test for matches longer than `matchLenMax` bytes mf:int match finder ID depthLimit:int match finder search depth limit

public static LZEncoder getInstance(int dictSize, int extraSizeBefore, int extraSizeAfter, int niceLen, int matchLenMax, int mf, int depthLimit, ArrayCache arrayCache)

Creates a new LZEncoder.

Parameters

dictSize:int: dictionary size
extraSizeBefore:int: number of bytes to keep available in the history in addition to dictSize
extraSizeAfter:int: number of bytes that must be available after current position + matchLenMax
niceLen:int: if a match of at least niceLen bytes is found, be happy with it and don't stop looking for longer matches
matchLenMax:int: don't test for matches longer than matchLenMax bytes
mf:int: match finder ID
depthLimit:int: match finder search depth limit

getMatches	back to summary
public abstract Matches getMatches() Runs match finder for the next byte and returns the matches found.

getMatchLen	back to summary
public int getMatchLen(int dist, int lenLimit) Get the length of a match at the given distance. Parameters dist:int zero-based distance of the match to test lenLimit:int don't test for a match longer than this Returns:int length of the match; it is in the range [0, lenLimit]

getMatchLen

back to summary

public int getMatchLen(int dist, int lenLimit)

Get the length of a match at the given distance.

Parameters

dist:int: zero-based distance of the match to test
lenLimit:int: don't test for a match longer than this

Returns:int

length of the match; it is in the range [0, lenLimit]

getMatchLen	back to summary
public int getMatchLen(int forward, int dist, int lenLimit) Get the length of a match at the given distance and forward offset. Parameters forward:int forward offset dist:int zero-based distance of the match to test lenLimit:int don't test for a match longer than this Returns:int length of the match; it is in the range [0, lenLimit]

getMatchLen

back to summary

public int getMatchLen(int forward, int dist, int lenLimit)

Get the length of a match at the given distance and forward offset.

Parameters

forward:int: forward offset
dist:int: zero-based distance of the match to test
lenLimit:int: don't test for a match longer than this

Returns:int

length of the match; it is in the range [0, lenLimit]

getMemoryUsage	back to summary
public static int getMemoryUsage(int dictSize, int extraSizeBefore, int extraSizeAfter, int matchLenMax, int mf) Gets approximate memory usage of the LZEncoder base structure and the match finder as kibibytes.

getPos	back to summary
public int getPos() Gets the lowest four bits of the absolute offset of the current byte. Bits other than the lowest four are undefined.

hasEnoughData	back to summary
public boolean hasEnoughData(int alreadyReadLen) Tests if there is enough input available to let the caller encode at least one more byte.

isStarted	back to summary
public boolean isStarted() Returns true if at least one byte has already been run through the match finder.

movePos	back to summary
pack-priv int movePos(int requiredForFlushing, int requiredForFinishing) Moves to the next byte, checks if there is enough input available, and returns the amount of input available. Parameters requiredForFlushing:int minimum number of available bytes when flushing; encoding may be continued with new input after flushing requiredForFinishing:int minimum number of available bytes when finishing; encoding must not be continued after finishing or the match finder state may be corrupt Returns:int the number of bytes available or zero if there is not enough input available

movePos

back to summary

pack-priv int movePos(int requiredForFlushing, int requiredForFinishing)

Moves to the next byte, checks if there is enough input available, and returns the amount of input available.

Parameters

requiredForFlushing:int: minimum number of available bytes when flushing; encoding may be continued with new input after flushing
requiredForFinishing:int: minimum number of available bytes when finishing; encoding must not be continued after finishing or the match finder state may be corrupt

Returns:int

the number of bytes available or zero if there is not enough input available

moveWindow	back to summary
private void moveWindow() Moves data from the end of the buffer to the beginning, discarding old data and making space for new input.

normalize	back to summary
pack-priv static void normalize(int[] positions, int positionsCount, int normalizationOffset)

processPendingBytes	back to summary
private void processPendingBytes() Process pending bytes remaining from preset dictionary initialization or encoder flush operation.

putArraysToCache	back to summary
public void putArraysToCache(ArrayCache arrayCache)

setFinishing	back to summary
public void setFinishing() Marks that there is no more input remaining. The read position can be advanced until the end of the data.

setFlushing	back to summary
public void setFlushing() Marks that all the input needs to be made available in the encoded output.

setPresetDict	back to summary
public void setPresetDict(int dictSize, byte[] presetDict) Sets a preset dictionary. If a preset dictionary is wanted, this function must be called immediately after creating the LZEncoder before any data has been encoded.

skip	back to summary
public abstract void skip(int len) Skips the given number of bytes in the match finder.

verifyMatches back to summary

verifyMatches	back to summary
public boolean verifyMatches(Matches matches) Verifies that the matches returned by the match finder are valid. This is meant to be used in an assert statement. This is totally useless for actual encoding since match finder's results should naturally always be valid if it isn't broken. Parameters matches:Matches return value from `getMatches` Returns:boolean true if matches are valid, false if match finder is broken

public boolean verifyMatches(Matches matches)

Verifies that the matches returned by the match finder are valid. This is meant to be used in an assert statement. This is totally useless for actual encoding since match finder's results should naturally always be valid if it isn't broken.

Parameters

matches:Matches: return value from getMatches

Returns:boolean

true if matches are valid, false if match finder is broken

public abstract Class LZEncoder

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