Deflater

BEST_COMPRESSION

static val BEST_COMPRESSION: Int

Compression level for best compression.

Value: 9

BEST_SPEED

static val BEST_SPEED: Int

Compression level for fastest compression.

Value: 1

DEFAULT_COMPRESSION

static val DEFAULT_COMPRESSION: Int

Default compression level.

Value: -1

DEFAULT_STRATEGY

static val DEFAULT_STRATEGY: Int

Default compression strategy.

Value: 0

DEFLATED

static val DEFLATED: Int

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

Value: 8

FILTERED

static val FILTERED: Int

Compression strategy best used for data consisting mostly of small values with a somewhat random distribution. Forces more Huffman coding and less string matching.

Value: 1

FULL_FLUSH

static val FULL_FLUSH: Int

Compression flush mode used to flush out all pending output and reset the deflater. Using this mode too often can seriously degrade compression.

Value: 3

HUFFMAN_ONLY

static val HUFFMAN_ONLY: Int

Compression strategy for Huffman coding only.

Value: 2

NO_COMPRESSION

static val NO_COMPRESSION: Int

Compression level for no compression.

Value: 0

NO_FLUSH

static val NO_FLUSH: Int

Compression flush mode used to achieve best compression result.

Value: 0

SYNC_FLUSH

static val SYNC_FLUSH: Int

Compression flush mode used to flush out all pending output; may degrade compression for some compression algorithms.

Value: 2

Deflater

Deflater()

Creates a new compressor with the default compression level. Compressed data will be generated in ZLIB format.

Deflater

Deflater(level: Int)

Creates a new compressor using the specified compression level. Compressed data will be generated in ZLIB format.

Deflater

Deflater(
    level: Int, 
    nowrap: Boolean)

Creates a new compressor using the specified compression level. 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.

deflate

open fun deflate(output: ByteArray!): Int

Compresses the input data and fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput should be called in order to determine if more input data is required.

This method uses NO_FLUSH as its compression flush mode. An invocation of this method of the form deflater.deflate(b) yields the same result as the invocation of deflater.deflate(b, 0, b.length, Deflater.NO_FLUSH).

deflate

open fun deflate(
    output: ByteArray!, 
    off: Int, 
    len: Int
): Int

Compresses the input data and fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput should be called in order to determine if more input data is required.

This method uses NO_FLUSH as its compression flush mode. An invocation of this method of the form deflater.deflate(b, off, len) yields the same result as the invocation of deflater.deflate(b, off, len, Deflater.NO_FLUSH).

deflate

open fun deflate(
    output: ByteArray!, 
    off: Int, 
    len: Int, 
    flush: Int
): Int

Compresses the input data and fills the specified buffer with compressed data. Returns actual number of bytes of data compressed.

Compression flush mode is one of the following three modes:

• NO_FLUSH: allows the deflater to decide how much data to accumulate, before producing output, in order to achieve the best compression (should be used in normal use scenario). A return value of 0 in this flush mode indicates that needsInput() should be called in order to determine if more input data is required.
• SYNC_FLUSH: all pending output in the deflater is flushed, to the specified output buffer, so that an inflater that works on compressed data can get all input data available so far (In particular the needsInput() returns true after this invocation if enough output space is provided). Flushing with SYNC_FLUSH may degrade compression for some compression algorithms and so it should be used only when necessary.
• FULL_FLUSH: all pending output is flushed out as with SYNC_FLUSH. The compression state is reset so that the inflater that works on the compressed output data can restart from this point if previous compressed data has been damaged or if random access is desired. Using FULL_FLUSH too often can seriously degrade compression.

In the case of FULL_FLUSH or SYNC_FLUSH, if the return value is len, the space available in output buffer b, this method should be invoked again with the same flush parameter and more output space. Make sure that len is greater than 6 to avoid flush marker (5 bytes) being repeatedly output to the output buffer every time this method is invoked.

If the setInput(java.nio.ByteBuffer) method was called to provide a buffer for input, the input buffer's position will be advanced by the number of bytes consumed by this operation.

deflate

open fun deflate(output: ByteBuffer!): Int

Compresses the input data and fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput should be called in order to determine if more input data is required.

This method uses NO_FLUSH as its compression flush mode. An invocation of this method of the form deflater.deflate(output) yields the same result as the invocation of deflater.deflate(output, Deflater.NO_FLUSH).

deflate

open fun deflate(
    output: ByteBuffer!, 
    flush: Int
): Int

Compresses the input data and fills the specified buffer with compressed data. Returns actual number of bytes of data compressed.

Compression flush mode is one of the following three modes:

• NO_FLUSH: allows the deflater to decide how much data to accumulate, before producing output, in order to achieve the best compression (should be used in normal use scenario). A return value of 0 in this flush mode indicates that needsInput() should be called in order to determine if more input data is required.
• SYNC_FLUSH: all pending output in the deflater is flushed, to the specified output buffer, so that an inflater that works on compressed data can get all input data available so far (In particular the needsInput() returns true after this invocation if enough output space is provided). Flushing with SYNC_FLUSH may degrade compression for some compression algorithms and so it should be used only when necessary.
• FULL_FLUSH: all pending output is flushed out as with SYNC_FLUSH. The compression state is reset so that the inflater that works on the compressed output data can restart from this point if previous compressed data has been damaged or if random access is desired. Using FULL_FLUSH too often can seriously degrade compression.

In the case of FULL_FLUSH or SYNC_FLUSH, if the return value is equal to the remaining space of the buffer, this method should be invoked again with the same flush parameter and more output space. Make sure that the buffer has at least 6 bytes of remaining space to avoid the flush marker (5 bytes) being repeatedly output to the output buffer every time this method is invoked.

On success, the position of the given output byte buffer will be advanced by as many bytes as were produced by the operation, which is equal to the number returned by this method.

If the setInput(java.nio.ByteBuffer) method was called to provide a buffer for input, the input buffer's position will be advanced by the number of bytes consumed by this operation.

end

open fun end(): Unit

Closes the compressor and discards any unprocessed input. This method should be called when the compressor is no longer being used. Once this method is called, the behavior of the Deflater object is undefined.

finish

open fun finish(): Unit

When called, indicates that compression should end with the current contents of the input buffer.

finished

open fun finished(): Boolean

Returns true if the end of the compressed data output stream has been reached.

getAdler

open fun getAdler(): Int

Returns the ADLER-32 value of the uncompressed data.

getBytesRead

open fun getBytesRead(): Long

Returns the total number of uncompressed bytes input so far.

getBytesWritten

open fun getBytesWritten(): Long

Returns the total number of compressed bytes output so far.

getTotalIn

open fun getTotalIn(): Int

Returns the total number of uncompressed bytes input so far.

Since the number of bytes may be greater than Integer.MAX_VALUE, the getBytesRead() method is now the preferred means of obtaining this information.

getTotalOut

open fun getTotalOut(): Int

Returns the total number of compressed bytes output so far.

Since the number of bytes may be greater than Integer.MAX_VALUE, the getBytesWritten() method is now the preferred means of obtaining this information.

needsInput

open fun needsInput(): Boolean

Returns true if no data remains in the input buffer. This can be used to determine if one of the setInput() methods should be called in order to provide more input.

reset

open fun reset(): Unit

Resets deflater so that a new set of input data can be processed. Keeps current compression level and strategy settings.

setDictionary

open fun setDictionary(dictionary: ByteArray!): Unit

Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined. When the data is later uncompressed with Inflater.inflate(), Inflater.getAdler() can be called in order to get the Adler-32 value of the dictionary required for decompression.

setDictionary

open fun setDictionary(
    dictionary: ByteArray!, 
    off: Int, 
    len: Int
): Unit

Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined. When the data is later uncompressed with Inflater.inflate(), Inflater.getAdler() can be called in order to get the Adler-32 value of the dictionary required for decompression.

setDictionary

open fun setDictionary(dictionary: ByteBuffer!): Unit

Sets preset dictionary for compression. A preset dictionary is used when the history buffer can be predetermined. When the data is later uncompressed with Inflater.inflate(), Inflater.getAdler() can be called in order to get the Adler-32 value of the dictionary required for decompression.

The bytes in given byte buffer will be fully consumed by this method. On return, its position will equal its limit.

setInput

open fun setInput(input: ByteArray!): Unit

Sets input data for compression.

One of the setInput() methods should be called whenever needsInput() returns true indicating that more input data is required.

setInput

open fun setInput(
    input: ByteArray!, 
    off: Int, 
    len: Int
): Unit

Sets input data for compression.

One of the setInput() methods should be called whenever needsInput() returns true indicating that more input data is required.

setInput

open fun setInput(input: ByteBuffer!): Unit

Sets input data for compression.

One of the setInput() methods should be called whenever needsInput() returns true indicating that more input data is required.

The given buffer's position will be advanced as deflate operations are performed, up to the buffer's limit. The input buffer may be modified (refilled) between deflate operations; doing so is equivalent to creating a new buffer and setting it with this method.

Modifying the input buffer's contents, position, or limit concurrently with an deflate operation will result in undefined behavior, which may include incorrect operation results or operation failure.

setLevel

open fun setLevel(level: Int): Unit

Sets the compression level to the specified value.

If the compression level is changed, the next invocation of deflate will compress the input available so far with the old level (and may be flushed); the new level will take effect only after that invocation.

setStrategy

open fun setStrategy(strategy: Int): Unit

Sets the compression strategy to the specified value.

If the compression strategy is changed, the next invocation of deflate will compress the input available so far with the old strategy (and may be flushed); the new strategy will take effect only after that invocation.