org.xerial.snappy
クラス Snappy

java.lang.Object
  org.xerial.snappy.Snappy

public class Snappy
extends Object

Snappy API for data compression/decompression

作成者:

leo

コンストラクタの概要

Snappy()

メソッドの概要

static byte[]	compress(byte[] input) High-level API for compressing the input byte array.
static int	compress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset) Compress the input buffer content in [inputOffset, ...inputOffset+inputLength) then output to the specified output buffer.
static int	compress(ByteBuffer uncompressed, ByteBuffer compressed) Compress the content in the given input buffer.
static String	getNativeLibraryVersion() Get the native library version of the snappy
static boolean	isValidCompressedBuffer(byte[] input, int offset, int length) Returns true iff the contents of compressed buffer [offset, offset+length) can be uncompressed successfully.
static boolean	isValidCompressedBuffer(ByteBuffer compressed) Returns true iff the contents of compressed buffer [pos() ... limit()) can be uncompressed successfully.
static int	maxCompressedLength(int byteSize) Get the maximum byte size needed for compressing a data of the given byte size.
static byte[]	uncompress(byte[] input) High-level API for uncompressing the input byte array.
static int	uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset) Uncompress the content in the input buffer.
static int	uncompress(ByteBuffer compressed, ByteBuffer uncompressed) Uncompress the content in the input buffer.
static int	uncompressedLength(byte[] input, int offset, int length) Get the uncompressed byte size of the given compressed input.
static int	uncompressedLength(ByteBuffer compressed) Get the uncompressed byte size of the given compressed input.

クラス java.lang.Object から継承されたメソッド

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

コンストラクタの詳細

Snappy

public Snappy()

メソッドの詳細

getNativeLibraryVersion

public static String getNativeLibraryVersion()

Get the native library version of the snappy

戻り値:

native library version

compress

public static byte[] compress(byte[] input)
                       throws SnappyException

High-level API for compressing the input byte array. This method performs array copy to generate the result. If you want to save this cost, use compress(byte[], int, int, byte[], int) or compress(ByteBuffer, ByteBuffer).

パラメータ:

input - the input data

戻り値:

the compressed byte array

例外:

SnappyException

uncompress

public static byte[] uncompress(byte[] input)
                         throws SnappyException

High-level API for uncompressing the input byte array.

パラメータ:

input -

戻り値:

the uncompressed byte array

例外:

SnappyException

compress

public static int compress(ByteBuffer uncompressed,
                           ByteBuffer compressed)
                    throws SnappyException

Compress the content in the given input buffer. After the compression, you can retrieve the compressed data from the output buffer [pos() ... limit()) (compressed data size = limit() - pos() = remaining())

パラメータ:

uncompressed - buffer[pos() ... limit()) containing the input data

compressed - output of the compressed data. Uses range [pos()..].

戻り値:

byte size of the compressed data.

例外:

SnappyError - when the input is not a direct buffer

SnappyException

compress

public static int compress(byte[] input,
                           int inputOffset,
                           int inputLength,
                           byte[] output,
                           int outputOffset)
                    throws SnappyException

Compress the input buffer content in [inputOffset, ...inputOffset+inputLength) then output to the specified output buffer.

パラメータ:

input -

inputOffset -

inputLength -

output -

outputOffset -

戻り値:

byte size of the compressed data

例外:

SnappyException - when failed to access the input/output buffer

uncompress

public static int uncompress(ByteBuffer compressed,
                             ByteBuffer uncompressed)
                      throws SnappyException

Uncompress the content in the input buffer. The result is dumped to the specified output buffer. Note that if you pass the wrong data or the range [pos(), limit()) that cannot be uncompressed, your JVM might crash due to the access violation exception issued in the native code written in C++. To avoid this type of crash, use isValidCompressedBuffer(ByteBuffer) first.

パラメータ:

compressed - buffer[pos() ... limit()) containing the input data

uncompressed - output of the the uncompressed data. It uses buffer[pot()..]

戻り値:

uncompressed data size

例外:

SnappyException - when failed to uncompress the given input

SnappyError - when the input is not a direct buffer

uncompress

public static int uncompress(byte[] input,
                             int inputOffset,
                             int inputLength,
                             byte[] output,
                             int outputOffset)
                      throws SnappyException

Uncompress the content in the input buffer. The uncompressed data is written to the output buffer. Note that if you pass the wrong data or the range [inputOffset, inputOffset + inputLength) that cannot be uncompressed, your JVM might crash due to the access violation exception issued in the native code written in C++. To avoid this type of crash, use isValidCompressedBuffer(byte[], int, int) first.

パラメータ:

input -

inputOffset -

inputLength -

output -

outputOffset -

戻り値:

the byte size of the uncompressed data

例外:

SnappyException

uncompressedLength

public static int uncompressedLength(ByteBuffer compressed)
                              throws SnappyException

Get the uncompressed byte size of the given compressed input. This operation taks O(1) time.

パラメータ:

compressed - input data [pos() ... limit())

戻り値:

uncompressed byte length of the given input

例外:

SnappyException - when failed to uncompress the given input. The error code is SnappyErrorCode.PARSING_ERROR

SnappyError - when the input is not a direct buffer

uncompressedLength

public static int uncompressedLength(byte[] input,
                                     int offset,
                                     int length)
                              throws SnappyException

Get the uncompressed byte size of the given compressed input. This operation takes O(1) time.

パラメータ:

input -

offset -

length -

戻り値:

umcompressed byte size of the the given input data

例外:

SnappyException - when failed to uncompress the given input. The error code is SnappyErrorCode.PARSING_ERROR

maxCompressedLength

public static int maxCompressedLength(int byteSize)

Get the maximum byte size needed for compressing a data of the given byte size.

パラメータ:

byteSize - byte size of the data to compress

戻り値:

maximum byte size of the compressed data

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(ByteBuffer compressed)
                                       throws SnappyException

Returns true iff the contents of compressed buffer [pos() ... limit()) can be uncompressed successfully. Does not return the uncompressed data. Takes time proportional to the input length, but is usually at least a factor of four faster than actual decompression.

例外:

SnappyException

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(byte[] input,
                                              int offset,
                                              int length)
                                       throws SnappyException

Returns true iff the contents of compressed buffer [offset, offset+length) can be uncompressed successfully. Does not return the uncompressed data. Takes time proportional to the input length, but is usually at least a factor of four faster than actual decompression.

例外:

SnappyException