Package net.sf.jazzlib

Class DeflaterEngine

java.lang.Object

net.sf.jazzlib.DeflaterEngine

All Implemented Interfaces:

DeflaterConstants

class DeflaterEngine
extends Object
implements DeflaterConstants

Field Summary

Fields

Modifier and Type	Field	Description
private final Adler32	adler	The adler checksum
private int	blockStart
private int	comprFunc	The current compression function.
private int	goodLength
private final short[]	head	Hashtable, hashing three characters to an index for window, so that window[index]..window[index+2] have this hash code.
private final DeflaterHuffman	huffman
private byte[]	inputBuf	The input data for compression.
private int	inputEnd	The end offset of the input data.
private int	inputOff	The offset into inputBuf, where input data starts.
private int	ins_h
private int	lookahead	lookahead is the number of characters starting at strstart in window that are valid.
private int	matchLen
private int	matchStart
private int	max_chain
private int	max_lazy
private int	niceLength
private final DeflaterPending	pending
private final short[]	prev	prev[index invalid input: '&' WMASK] points to the previous index that has the same hash code as the string starting at index.
private boolean	prevAvailable
private int	strategy
private int	strstart	strstart points to the current character in window.
private static final int	TOO_FAR
private int	totalIn	The total bytes of input read.
private final byte[]	window	This array contains the part of the uncompressed stream that is of relevance.

Fields inherited from interface net.sf.jazzlib.DeflaterConstants

COMPR_FUNC, DEBUGGING, DEFAULT_MEM_LEVEL, DEFLATE_FAST, DEFLATE_SLOW, DEFLATE_STORED, DYN_TREES, GOOD_LENGTH, HASH_BITS, HASH_MASK, HASH_SHIFT, HASH_SIZE, MAX_BLOCK_SIZE, MAX_CHAIN, MAX_DIST, MAX_LAZY, MAX_MATCH, MAX_WBITS, MIN_LOOKAHEAD, MIN_MATCH, NICE_LENGTH, PENDING_BUF_SIZE, PRESET_DICT, STATIC_TREES, STORED_BLOCK, WMASK, WSIZE

Constructor Summary

Constructors

Constructor	Description
DeflaterEngine(DeflaterPending pending)

Method Summary

Modifier and Type	Method	Description
boolean	deflate(boolean flush, boolean finish)
private boolean	deflateFast(boolean flush, boolean finish)
private boolean	deflateSlow(boolean flush, boolean finish)
private boolean	deflateStored(boolean flush, boolean finish)
private void	fillWindow()	Fill the window when the lookahead becomes insufficient.
private boolean	findLongestMatch(int curMatch)	Find the best (longest) string in the window matching the string starting at strstart.
final int	getAdler()
final int	getTotalIn()
private final int	insertString()	Inserts the current string in the head hash and returns the previous value for this hash.
final boolean	needsInput()
void	reset()
final void	resetAdler()
(package private) void	setDictionary(byte[] buffer, int offset, int length)
void	setInput(byte[] buf, int off, int len)
void	setLevel(int lvl)
final void	setStrategy(int strat)
private void	slideWindow()
private final void	updateHash()

Methods inherited from class java.lang.Object

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

Field Details

TOO_FAR

private static final int TOO_FAR

See Also:

• Constant Field Values

ins_h

private int ins_h

head

private final short[] head

Hashtable, hashing three characters to an index for window, so that window[index]..window[index+2] have this hash code. Note that the array should really be unsigned short, so you need to and the values with 0xffff.

prev

private final short[] prev

prev[index invalid input: '&' WMASK] points to the previous index that has the same hash code as the string starting at index. This way entries with the same hash code are in a linked list. Note that the array should really be unsigned short, so you need to and the values with 0xffff.

matchStart

private int matchStart

matchLen

private int matchLen

prevAvailable

private boolean prevAvailable

blockStart

private int blockStart

strstart

private int strstart

strstart points to the current character in window.

lookahead

private int lookahead

lookahead is the number of characters starting at strstart in window that are valid. So window[strstart] until window[strstart+lookahead-1] are valid characters.

window

private final byte[] window

This array contains the part of the uncompressed stream that is of relevance. The current character is indexed by strstart.

strategy

private int strategy

max_chain

private int max_chain

max_lazy

private int max_lazy

niceLength

private int niceLength

goodLength

private int goodLength

comprFunc

private int comprFunc

The current compression function.

inputBuf

private byte[] inputBuf

The input data for compression.

totalIn

private int totalIn

The total bytes of input read.

inputOff

private int inputOff

The offset into inputBuf, where input data starts.

inputEnd

private int inputEnd

The end offset of the input data.

pending

private final DeflaterPending pending

huffman

private final DeflaterHuffman huffman

adler

private final Adler32 adler

The adler checksum

Constructor Details

DeflaterEngine

DeflaterEngine(DeflaterPending pending)

Method Details

reset

public void reset()

resetAdler

public final void resetAdler()

getAdler

public final int getAdler()

getTotalIn

public final int getTotalIn()

setStrategy

public final void setStrategy(int strat)

setLevel

public void setLevel(int lvl)

updateHash

private final void updateHash()

insertString

private final int insertString()

Inserts the current string in the head hash and returns the previous value for this hash.

slideWindow

private void slideWindow()

fillWindow

private void fillWindow()

Fill the window when the lookahead becomes insufficient. Updates strstart and lookahead. OUT assertions: strstart + lookahead invalid input: '<'= 2*WSIZE lookahead >= MIN_LOOKAHEAD or inputOff == inputEnd

findLongestMatch

private boolean findLongestMatch(int curMatch)

Find the best (longest) string in the window matching the string starting at strstart. Preconditions: strstart + MAX_MATCH invalid input: '<'= window.length.

Parameters:

curMatch -

setDictionary

void setDictionary(byte[] buffer,
 int offset,
 int length)

deflateStored

private boolean deflateStored(boolean flush,
 boolean finish)

deflateFast

private boolean deflateFast(boolean flush,
 boolean finish)

deflateSlow

private boolean deflateSlow(boolean flush,
 boolean finish)

deflate

public boolean deflate(boolean flush,
 boolean finish)

setInput

public void setInput(byte[] buf,
 int off,
 int len)

needsInput

public final boolean needsInput()