totalcross.util.zip

Class ZLib

java.lang.Object

totalcross.util.zip.ZLib

public final class ZLib
extends java.lang.Object

This class implements stream compression with the ZLib library.

zlib is designed to be a free, general-purpose, legally unencumbered - that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms.

http://www.zlib.net/

Field Summary

Fields

Modifier and Type	Field and Description
static int	BEST_COMPRESSION Compression level for best compression, which is 9 in a scale from 0 (no compression) to 9 (best compression).
static int	BEST_SPEED Compression level for fastest compression, which is 1 in a scale from 0 (no compression) to 9 (best compression).
static int	DEFAULT_COMPRESSION Default compression level.
static int	DEFAULT_STRATEGY Default compression strategy.
static int	DEFLATED Compression method for the deflate algorithm (the only one currently supported).
static int	FILTERED Compression strategy best used for data consisting mostly of small values with a somewhat random distribution.
static int	HUFFMAN_ONLY Compression strategy for Huffman coding only.
static int	NO_COMPRESSION Compression level for no compression, which is 0 in a scale from 0 (no compression) to 9 (best compression)

Method Summary

Modifier and Type	Method and Description
static int	deflate(int compressionLevel, Stream in, Stream out) Deprecated. use #deflate(Stream, Stream, int) instead
static int	deflate(Stream in, Stream out) Deflates the given stream 'in' with the specified compression level, writing the result to the given stream 'out'.
static int	deflate(Stream in, Stream out, int compressionLevel) Deflates the given stream 'in' with the specified compression level, writing the result to the given stream 'out'.
static int	deflate(Stream in, Stream out, int compressionLevel, int strategy, boolean noWrap) Deflates the given stream 'in' using the specified strategy and compression level, writing the result to the given stream 'out'.
static int	inflate(Stream in, Stream out) Attempts to fully read the given stream 'in', inflating and writing to the given stream 'out'.
static int	inflate(Stream in, Stream out, int sizeIn) Attempts to read the number of bytes specified by 'sizeIn' from the the given stream 'in', inflating and writing to the given stream 'out'.
static int	inflate(Stream in, Stream out, int sizeIn, boolean noWrap) Attempts to read the number of bytes specified by 'sizeIn' from the the given stream 'in', inflating and writing to the given stream 'out'.

Methods inherited from class java.lang.Object

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

Field Detail

NO_COMPRESSION

public static final int NO_COMPRESSION

Compression level for no compression, which is 0 in a scale from 0 (no compression) to 9 (best compression)

See Also:

Constant Field Values

BEST_SPEED

public static final int BEST_SPEED

Compression level for fastest compression, which is 1 in a scale from 0 (no compression) to 9 (best compression).

See Also:

Constant Field Values

BEST_COMPRESSION

public static final int BEST_COMPRESSION

Compression level for best compression, which is 9 in a scale from 0 (no compression) to 9 (best compression).

See Also:

Constant Field Values

DEFAULT_COMPRESSION

public static final int DEFAULT_COMPRESSION

Default compression level.

See Also:

Constant Field Values

DEFAULT_STRATEGY

public static final int DEFAULT_STRATEGY

Default compression strategy.

See Also:

Constant Field Values

DEFLATED

public static final int DEFLATED

Compression method for the deflate algorithm (the only one currently supported).

See Also:

Constant Field Values

FILTERED

public static final int FILTERED

Compression strategy best used for data consisting mostly of small values with a somewhat random distribution.

See Also:

Constant Field Values

HUFFMAN_ONLY

public static final int HUFFMAN_ONLY

Compression strategy for Huffman coding only.

See Also:

Constant Field Values

Method Detail

deflate

public static int deflate(Stream in,
                          Stream out)
                   throws IOException

Deflates the given stream 'in' with the specified compression level, writing the result to the given stream 'out'. Compressed data will be generated in ZLIB format using the default strategy and the default compression level.

Parameters:

in - Stream to be deflated

out - Deflated stream.

Returns:

Size of the deflated stream

Throws:

IOException

See Also:

DEFAULT_COMPRESSION

deflate

public static int deflate(Stream in,
                          Stream out,
                          int compressionLevel)
                   throws IOException

Deflates the given stream 'in' with the specified compression level, writing the result to the given stream 'out'. Compressed data will be generated in ZLIB format using the default strategy.

Parameters:

in - Stream to be deflated

out - Deflated stream.

compressionLevel - Desired compression level, which must be between 0 and 9, or -1 for the default compression level

Returns:

Size of the deflated stream

Throws:

IOException

See Also:

NO_COMPRESSION, BEST_SPEED, BEST_COMPRESSION

deflate

@Deprecated
public static int deflate(int compressionLevel,
                                      Stream in,
                                      Stream out)
                               throws IOException

Deprecated. use #deflate(Stream, Stream, int) instead

Deflates the given stream 'in' with the specified compression level, writing the result to the given stream 'out'. Compressed data will be generated in ZLIB format using the default strategy.

Parameters:

compressionLevel - Desired compression level, which must be between 0 and 9, or -1 for the default compression level

in - Stream to be deflated

out - Deflated stream.

Returns:

Size of the deflated stream

Throws:

IOException

See Also:

NO_COMPRESSION, BEST_SPEED, BEST_COMPRESSION

deflate

public static int deflate(Stream in,
                          Stream out,
                          int compressionLevel,
                          int strategy,
                          boolean noWrap)
                   throws IOException

Deflates the given stream 'in' using the specified strategy and compression level, writing the result to the given stream 'out'. If 'nowrap' is true then the ZLIB header and checksum fields will not be used in order to support the compression format used in both GZIP and PKZIP.

Parameters:

in - Stream to be deflated

out - Deflated stream.

compressionLevel - compression level, which must be between 0 and 9, or -1 for the default compression level

strategy - the compression strategy

noWrap - if true then use GZIP compatible compression

Returns:

Size of the deflated stream

Throws:

IOException

See Also:

NO_COMPRESSION, BEST_SPEED, BEST_COMPRESSION

inflate

public static int inflate(Stream in,
                          Stream out)
                   throws IOException,
                          ZipException

Attempts to fully read the given stream 'in', inflating and writing to the given stream 'out'.

Parameters:

in - Deflated input stream

out - Inflated output stream

Returns:

Size of the inflated stream

Throws:

IOException

ZipException

inflate

public static int inflate(Stream in,
                          Stream out,
                          int sizeIn)
                   throws IOException,
                          ZipException

Attempts to read the number of bytes specified by 'sizeIn' from the the given stream 'in', inflating and writing to the given stream 'out'. If 'sizeIn' is -1, it will attempt to fully read the stream.

Parameters:

in - Deflated input stream

out - Inflated output stream

sizeIn - How many bytes to read, or -1 to read until in's end

Returns:

Size of the inflated stream

Throws:

ZipException

IOException

inflate

public static int inflate(Stream in,
                          Stream out,
                          int sizeIn,
                          boolean noWrap)
                   throws IOException,
                          ZipException

Attempts to read the number of bytes specified by 'sizeIn' from the the given stream 'in', inflating and writing to the given stream 'out'. If 'sizeIn' is -1, it will attempt to fully read the stream. If the parameter 'noWrap' is true then the ZLIB header and checksum fields will not be used. This provides compatibility with the compression format used by both GZIP and PKZIP.
Note: When using the 'noWrap' option it is also necessary to provide an extra "dummy" byte as input. This is required by the ZLIB native library in order to support certain optimizations.

Parameters:

in - Deflated input stream

out - Inflated output stream

sizeIn - How many bytes to read, or -1 to read until in's end

noWrap - if true then support GZIP compatible compression

Returns:

Size of the inflated stream

Throws:

ZipException

IOException