org.xerial.snappy

Class Snappy

java.lang.Object

org.xerial.snappy.Snappy

public class Snappy
extends java.lang.Object

Snappy API for data compression/decompression

Note: if the native libraries cannot be loaded, an ExceptionInInitializerError will be thrown at first use of this class.

Constructor Summary

Constructors

Constructor and Description
Snappy()

Method Summary

Modifier and Type	Method and Description
static void	arrayCopy(java.lang.Object src, int offset, int byteLength, java.lang.Object dest, int dest_offset) Copy bytes from source to destination
static void	cleanUp() Clean up a temporary file (native lib) generated by snappy-java.
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(java.nio.ByteBuffer uncompressed, java.nio.ByteBuffer compressed) Compress the content in the given input buffer.
static byte[]	compress(char[] input) Compress the input char array
static byte[]	compress(double[] input) Compress the input double array
static byte[]	compress(float[] input) Compress the input float array
static byte[]	compress(int[] input) Compress the input int array
static byte[]	compress(long[] input) Compress the input long array
static byte[]	compress(short[] input) Compress the input short array
static byte[]	compress(java.lang.String s) Compress the input String
static byte[]	compress(java.lang.String s, java.nio.charset.Charset encoding) Compress the input string using the given encoding
static byte[]	compress(java.lang.String s, java.lang.String encoding) Compress the input string using the given encoding
static java.lang.String	getNativeLibraryVersion() Get the native library version of the snappy
static boolean	isValidCompressedBuffer(byte[] input) Returns true iff the contents of compressed buffer [offset, offset+length) can be uncompressed successfully.
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(java.nio.ByteBuffer compressed) Returns true iff the contents of compressed buffer [pos() ...
static boolean	isValidCompressedBuffer(long inputAddr, long offset, long length) Returns true iff the contents of compressed buffer [offset, offset+length) can be uncompressed successfully.
static int	maxCompressedLength(int byteSize) Get the maximum byte size needed for compressing data of the given byte size.
static long	rawCompress(long inputAddr, long inputSize, long destAddr) Zero-copy compress using memory addresses.
static byte[]	rawCompress(java.lang.Object data, int byteSize) Compress the input data and produce a byte array of the uncompressed data
static int	rawCompress(java.lang.Object input, int inputOffset, int inputLength, byte[] output, int outputOffset) Compress the input buffer [offset,...
static int	rawUncompress(byte[] input, int inputOffset, int inputLength, java.lang.Object output, int outputOffset) Uncompress the content in the input buffer.
static long	rawUncompress(long inputAddr, long inputSize, long destAddr) Zero-copy decompress using memory addresses.
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(java.nio.ByteBuffer compressed, java.nio.ByteBuffer uncompressed) Uncompress the content in the input buffer.
static char[]	uncompressCharArray(byte[] input) Uncompress the input data as char array
static char[]	uncompressCharArray(byte[] input, int offset, int length) Uncompress the input[offset, .., offset+length) as a char array
static double[]	uncompressDoubleArray(byte[] input) Uncompress the input as a double array
static int	uncompressedLength(byte[] input) Get the uncompressed byte size of the given compressed input.
static int	uncompressedLength(byte[] input, int offset, int length) Get the uncompressed byte size of the given compressed input.
static int	uncompressedLength(java.nio.ByteBuffer compressed) Get the uncompressed byte size of the given compressed input.
static long	uncompressedLength(long inputAddr, long len) Get the uncompressed byte size of the given compressed input.
static float[]	uncompressFloatArray(byte[] input) Uncompress the input as a float array
static float[]	uncompressFloatArray(byte[] input, int offset, int length) Uncompress the input[offset, offset+length) as a float array
static int[]	uncompressIntArray(byte[] input) Uncompress the input data as an int array
static int[]	uncompressIntArray(byte[] input, int offset, int length) Uncompress the input[offset, offset+length) as an int array
static long[]	uncompressLongArray(byte[] input) Uncompress the input data as a long array
static long[]	uncompressLongArray(byte[] input, int offset, int length) Uncompress the input[offset, offset+length) as a long array
static short[]	uncompressShortArray(byte[] input) Uncompress the input as a short array
static short[]	uncompressShortArray(byte[] input, int offset, int length) Uncompress the input[offset, offset+length) as a short array
static java.lang.String	uncompressString(byte[] input) Uncompress the input as a String
static java.lang.String	uncompressString(byte[] input, java.nio.charset.Charset encoding) Uncompress the input as a String of the given encoding
static java.lang.String	uncompressString(byte[] input, int offset, int length) Uncompress the input[offset, offset+length) as a String
static java.lang.String	uncompressString(byte[] input, int offset, int length, java.nio.charset.Charset encoding) Uncompress the input[offset, offset+length) as a String of the given encoding
static java.lang.String	uncompressString(byte[] input, int offset, int length, java.lang.String encoding) Uncompress the input[offset, offset+length) as a String of the given encoding
static java.lang.String	uncompressString(byte[] input, java.lang.String encoding) Uncompress the input as a String of the given encoding

Methods inherited from class java.lang.Object

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

Constructor Detail

Snappy

public Snappy()

Method Detail

cleanUp

public static void cleanUp()

Clean up a temporary file (native lib) generated by snappy-java. General users do not need to call this method, since the native library extracted in snappy-java is deleted upon JVM termination (vie deleteOnExit()). This method is useful when using a J2EE container, which will restart servlet containers multiple times without restarting JVM.

arrayCopy

public static void arrayCopy(java.lang.Object src,
                             int offset,
                             int byteLength,
                             java.lang.Object dest,
                             int dest_offset)
                      throws java.io.IOException

Copy bytes from source to destination

Parameters:

src - pointer to the source array

offset - byte offset in the source array

byteLength - the number of bytes to copy

dest - pointer to the destination array

dest_offset - byte offset in the destination array

Throws:

java.io.IOException

compress

public static byte[] compress(byte[] input)
                       throws java.io.IOException

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

Parameters:

input - the input data

Returns:

the compressed byte array

Throws:

java.io.IOException

compress

public static int compress(byte[] input,
                           int inputOffset,
                           int inputLength,
                           byte[] output,
                           int outputOffset)
                    throws java.io.IOException

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

Parameters:

input -

inputOffset -

inputLength -

output -

outputOffset -

Returns:

byte size of the compressed data

Throws:

java.io.IOException - when failed to access the input/output buffer

compress

public static int compress(java.nio.ByteBuffer uncompressed,
                           java.nio.ByteBuffer compressed)
                    throws java.io.IOException

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())

Parameters:

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

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

Returns:

byte size of the compressed data.

Throws:

SnappyError - when the input is not a direct buffer

java.io.IOException

compress

public static byte[] compress(char[] input)
                       throws java.io.IOException

Compress the input char array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(double[] input)
                       throws java.io.IOException

Compress the input double array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(float[] input)
                       throws java.io.IOException

Compress the input float array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(int[] input)
                       throws java.io.IOException

Compress the input int array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(long[] input)
                       throws java.io.IOException

Compress the input long array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(short[] input)
                       throws java.io.IOException

Compress the input short array

Parameters:

input -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(java.lang.String s)
                       throws java.io.IOException

Compress the input String

Parameters:

s -

Returns:

the compressed data

Throws:

java.io.IOException

compress

public static byte[] compress(java.lang.String s,
                              java.lang.String encoding)
                       throws java.io.UnsupportedEncodingException,
                              java.io.IOException

Compress the input string using the given encoding

Parameters:

s -

encoding -

Returns:

the compressed data

Throws:

java.io.UnsupportedEncodingException

java.io.IOException

compress

public static byte[] compress(java.lang.String s,
                              java.nio.charset.Charset encoding)
                       throws java.io.IOException

Compress the input string using the given encoding

Parameters:

s -

encoding -

Returns:

the compressed data

Throws:

java.io.UnsupportedEncodingException

java.io.IOException

getNativeLibraryVersion

public static java.lang.String getNativeLibraryVersion()

Get the native library version of the snappy

Returns:

native library version

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(byte[] input,
                                              int offset,
                                              int length)
                                       throws java.io.IOException

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.

Throws:

java.io.IOException

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(byte[] input)
                                       throws java.io.IOException

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.

Throws:

java.io.IOException

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(java.nio.ByteBuffer compressed)
                                       throws java.io.IOException

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.

Throws:

java.io.IOException

isValidCompressedBuffer

public static boolean isValidCompressedBuffer(long inputAddr,
                                              long offset,
                                              long length)
                                       throws java.io.IOException

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.

Throws:

java.io.IOException

maxCompressedLength

public static int maxCompressedLength(int byteSize)

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

Parameters:

byteSize - byte size of the data to compress

Returns:

maximum byte size of the compressed data

rawCompress

public static long rawCompress(long inputAddr,
                               long inputSize,
                               long destAddr)
                        throws java.io.IOException

Zero-copy compress using memory addresses.

Parameters:

inputAddr - input memory address

inputSize - input byte size

destAddr - destination address of the compressed data

Returns:

the compressed data size

Throws:

java.io.IOException

rawUncompress

public static long rawUncompress(long inputAddr,
                                 long inputSize,
                                 long destAddr)
                          throws java.io.IOException

Zero-copy decompress using memory addresses.

Parameters:

inputAddr - input memory address

inputSize - input byte size

destAddr - destination address of the uncompressed data

Returns:

the uncompressed data size

Throws:

java.io.IOException

rawCompress

public static byte[] rawCompress(java.lang.Object data,
                                 int byteSize)
                          throws java.io.IOException

Compress the input data and produce a byte array of the uncompressed data

Parameters:

data - input array. The input MUST be an array type

byteSize - the input byte size

Returns:

compressed data

Throws:

java.io.IOException

rawCompress

public static int rawCompress(java.lang.Object input,
                              int inputOffset,
                              int inputLength,
                              byte[] output,
                              int outputOffset)
                       throws java.io.IOException

Compress the input buffer [offset,... ,offset+length) contents, then write the compressed data to the output buffer[offset, ...)

Parameters:

input - input array. This MUST be a primitive array type

inputOffset - byte offset at the output array

inputLength - byte length of the input data

output - output array. This MUST be a primitive array type

outputOffset - byte offset at the output array

Returns:

byte size of the compressed data

Throws:

java.io.IOException

rawUncompress

public static int rawUncompress(byte[] input,
                                int inputOffset,
                                int inputLength,
                                java.lang.Object output,
                                int outputOffset)
                         throws java.io.IOException

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.

Parameters:

input - input byte array

inputOffset - byte offset in the input byte array

inputLength - byte length of the input data

output - output buffer, MUST be a primitive type array

outputOffset - byte offset in the output buffer

Returns:

the byte size of the uncompressed data

Throws:

java.io.IOException - when failed to uncompress the input data

uncompress

public static byte[] uncompress(byte[] input)
                         throws java.io.IOException

High-level API for uncompressing the input byte array.

Parameters:

input -

Returns:

the uncompressed byte array

Throws:

java.io.IOException

uncompress

public static int uncompress(byte[] input,
                             int inputOffset,
                             int inputLength,
                             byte[] output,
                             int outputOffset)
                      throws java.io.IOException

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.

Parameters:

input -

inputOffset -

inputLength -

output -

outputOffset -

Returns:

the byte size of the uncompressed data

Throws:

java.io.IOException

uncompress

public static int uncompress(java.nio.ByteBuffer compressed,
                             java.nio.ByteBuffer uncompressed)
                      throws java.io.IOException

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.

Parameters:

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

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

Returns:

uncompressed data size

Throws:

java.io.IOException - when failed to uncompress the given input

SnappyError - when the input is not a direct buffer

uncompressCharArray

public static char[] uncompressCharArray(byte[] input)
                                  throws java.io.IOException

Uncompress the input data as char array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressCharArray

public static char[] uncompressCharArray(byte[] input,
                                         int offset,
                                         int length)
                                  throws java.io.IOException

Uncompress the input[offset, .., offset+length) as a char array

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressDoubleArray

public static double[] uncompressDoubleArray(byte[] input)
                                      throws java.io.IOException

Uncompress the input as a double array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressedLength

public static int uncompressedLength(byte[] input)
                              throws java.io.IOException

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

Parameters:

input -

Returns:

uncompressed byte size of the the given input data

Throws:

java.io.IOException - when failed to uncompress the given input. The error code is SnappyErrorCode.PARSING_ERROR

uncompressedLength

public static int uncompressedLength(byte[] input,
                                     int offset,
                                     int length)
                              throws java.io.IOException

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

Parameters:

input -

offset -

length -

Returns:

uncompressed byte size of the the given input data

Throws:

java.io.IOException - when failed to uncompress the given input. The error code is SnappyErrorCode.PARSING_ERROR

uncompressedLength

public static int uncompressedLength(java.nio.ByteBuffer compressed)
                              throws java.io.IOException

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

Parameters:

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

Returns:

uncompressed byte length of the given input

Throws:

java.io.IOException - 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 long uncompressedLength(long inputAddr,
                                      long len)
                               throws java.io.IOException

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

Parameters:

inputAddr - compressed data address

len - byte length of the input

Returns:

uncompressed byte length of the given input

Throws:

java.io.IOException - when failed to uncompress the given input. The error code is SnappyErrorCode.PARSING_ERROR

uncompressFloatArray

public static float[] uncompressFloatArray(byte[] input)
                                    throws java.io.IOException

Uncompress the input as a float array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressFloatArray

public static float[] uncompressFloatArray(byte[] input,
                                           int offset,
                                           int length)
                                    throws java.io.IOException

Uncompress the input[offset, offset+length) as a float array

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressIntArray

public static int[] uncompressIntArray(byte[] input)
                                throws java.io.IOException

Uncompress the input data as an int array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressIntArray

public static int[] uncompressIntArray(byte[] input,
                                       int offset,
                                       int length)
                                throws java.io.IOException

Uncompress the input[offset, offset+length) as an int array

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressLongArray

public static long[] uncompressLongArray(byte[] input)
                                  throws java.io.IOException

Uncompress the input data as a long array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressLongArray

public static long[] uncompressLongArray(byte[] input,
                                         int offset,
                                         int length)
                                  throws java.io.IOException

Uncompress the input[offset, offset+length) as a long array

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressShortArray

public static short[] uncompressShortArray(byte[] input)
                                    throws java.io.IOException

Uncompress the input as a short array

Parameters:

input -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressShortArray

public static short[] uncompressShortArray(byte[] input,
                                           int offset,
                                           int length)
                                    throws java.io.IOException

Uncompress the input[offset, offset+length) as a short array

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressString

public static java.lang.String uncompressString(byte[] input)
                                         throws java.io.IOException

Uncompress the input as a String

Parameters:

input -

Returns:

the uncompressed dasta

Throws:

java.io.IOException

uncompressString

public static java.lang.String uncompressString(byte[] input,
                                                int offset,
                                                int length)
                                         throws java.io.IOException

Uncompress the input[offset, offset+length) as a String

Parameters:

input -

offset -

length -

Returns:

the uncompressed data

Throws:

java.io.IOException

uncompressString

public static java.lang.String uncompressString(byte[] input,
                                                int offset,
                                                int length,
                                                java.lang.String encoding)
                                         throws java.io.IOException,
                                                java.io.UnsupportedEncodingException

Uncompress the input[offset, offset+length) as a String of the given encoding

Parameters:

input -

offset -

length -

encoding -

Returns:

the uncompressed data

Throws:

java.io.IOException

java.io.UnsupportedEncodingException

uncompressString

public static java.lang.String uncompressString(byte[] input,
                                                int offset,
                                                int length,
                                                java.nio.charset.Charset encoding)
                                         throws java.io.IOException,
                                                java.io.UnsupportedEncodingException

Uncompress the input[offset, offset+length) as a String of the given encoding

Parameters:

input -

offset -

length -

encoding -

Returns:

the uncompressed data

Throws:

java.io.IOException

java.io.UnsupportedEncodingException

uncompressString

public static java.lang.String uncompressString(byte[] input,
                                                java.lang.String encoding)
                                         throws java.io.IOException,
                                                java.io.UnsupportedEncodingException

Uncompress the input as a String of the given encoding

Parameters:

input -

encoding -

Returns:

the uncompressed data

Throws:

java.io.IOException

java.io.UnsupportedEncodingException

uncompressString

public static java.lang.String uncompressString(byte[] input,
                                                java.nio.charset.Charset encoding)
                                         throws java.io.IOException,
                                                java.io.UnsupportedEncodingException

Uncompress the input as a String of the given encoding

Parameters:

input -

encoding -

Returns:

the uncompressed data

Throws:

java.io.IOException

java.io.UnsupportedEncodingException