com.ning.compress.lzf

Class LZFEncoder

java.lang.Object

com.ning.compress.lzf.LZFEncoder

public class LZFEncoder
extends Object

Encoder that handles splitting of input into chunks to encode, calls ChunkEncoder to compress individual chunks and combines resulting chunks into contiguous output byte array.

Author:

Tatu Saloranta

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_CHUNK_RESULT_SIZE

Method Summary

Methods

Modifier and Type	Method and Description
static int	appendEncoded(byte[] input, int inputPtr, int inputLength, byte[] outputBuffer, int outputPtr) Alternate version that accepts pre-allocated output buffer.
static int	appendEncoded(byte[] input, int inputPtr, int inputLength, byte[] outputBuffer, int outputPtr, BufferRecycler bufferRecycler) Alternate version that accepts pre-allocated output buffer.
static int	appendEncoded(ChunkEncoder enc, byte[] input, int inputPtr, int inputLength, byte[] outputBuffer, int outputPtr) Alternate version that accepts pre-allocated output buffer.
static byte[]	encode(byte[] data) Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility).
static byte[]	encode(byte[] data, int offset, int length) Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility).
static byte[]	encode(byte[] data, int offset, int length, BufferRecycler bufferRecycler) Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility).
static byte[]	encode(ChunkEncoder enc, byte[] data, int length) Compression method that uses specified ChunkEncoder for actual encoding.
static byte[]	encode(ChunkEncoder enc, byte[] data, int offset, int length) Method that encodes given input using provided ChunkEncoder, and aggregating it into a single byte array and returning that.
static int	estimateMaxWorkspaceSize(int inputSize) Helper method that can be used to estimate maximum space needed to try compression of given amount of data.
static int	safeAppendEncoded(byte[] input, int inputPtr, int inputLength, byte[] outputBuffer, int outputPtr) Alternate version that accepts pre-allocated output buffer.
static int	safeAppendEncoded(byte[] input, int inputPtr, int inputLength, byte[] outputBuffer, int outputPtr, BufferRecycler bufferRecycler) Alternate version that accepts pre-allocated output buffer.
static byte[]	safeEncode(byte[] data) Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding.
static byte[]	safeEncode(byte[] data, int offset, int length) Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding.
static byte[]	safeEncode(byte[] data, int offset, int length, BufferRecycler bufferRecycler) Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_CHUNK_RESULT_SIZE

public static final int MAX_CHUNK_RESULT_SIZE

See Also:

Constant Field Values

Method Detail

estimateMaxWorkspaceSize

public static int estimateMaxWorkspaceSize(int inputSize)

Helper method that can be used to estimate maximum space needed to try compression of given amount of data. This is slightly larger than maximum resulting content since compressor has a choice of uncompressed chunks to use, but that is only done after compression fails to reduce size; and this temporary expansion of up to 3.3% or so (1 indicator for every 31 bytes of uncompressed data) is more than what eventual expansion would be (5 bytes header per each uncompressed chunk, usually 0.01%).

encode

public static byte[] encode(byte[] data)

Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility). Result consists of a sequence of chunks.

Note that ChunkEncoder instance used is one produced by ChunkEncoderFactory.optimalInstance(), which typically is "unsafe" instance if one can be used on current JVM.

safeEncode

public static byte[] safeEncode(byte[] data)

Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding. Safe here means that it does not use any non-compliant features beyond core JDK.

encode

public static byte[] encode(byte[] data,
            int offset,
            int length)

Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility). Result consists of a sequence of chunks.

Note that ChunkEncoder instance used is one produced by ChunkEncoderFactory.optimalInstance(), which typically is "unsafe" instance if one can be used on current JVM.

safeEncode

public static byte[] safeEncode(byte[] data,
                int offset,
                int length)

Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding. Safe here means that it does not use any non-compliant features beyond core JDK.

encode

public static byte[] encode(byte[] data,
            int offset,
            int length,
            BufferRecycler bufferRecycler)

Method for compressing given input data using LZF encoding and block structure (compatible with lzf command line utility). Result consists of a sequence of chunks.

Note that ChunkEncoder instance used is one produced by ChunkEncoderFactory.optimalInstance(), which typically is "unsafe" instance if one can be used on current JVM.

safeEncode

public static byte[] safeEncode(byte[] data,
                int offset,
                int length,
                BufferRecycler bufferRecycler)

Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding. Safe here means that it does not use any non-compliant features beyond core JDK.

encode

public static byte[] encode(ChunkEncoder enc,
            byte[] data,
            int length)

Compression method that uses specified ChunkEncoder for actual encoding.

encode

public static byte[] encode(ChunkEncoder enc,
            byte[] data,
            int offset,
            int length)

Method that encodes given input using provided ChunkEncoder, and aggregating it into a single byte array and returning that.

NOTE: method does NOT call ChunkEncoder.close(); caller is responsible for doing that after it is done using the encoder.

appendEncoded

public static int appendEncoded(byte[] input,
                int inputPtr,
                int inputLength,
                byte[] outputBuffer,
                int outputPtr)

Alternate version that accepts pre-allocated output buffer.

Note that ChunkEncoder instance used is one produced by ChunkEncoderFactory.optimalNonAllocatingInstance(int), which typically is "unsafe" instance if one can be used on current JVM.

safeAppendEncoded

public static int safeAppendEncoded(byte[] input,
                    int inputPtr,
                    int inputLength,
                    byte[] outputBuffer,
                    int outputPtr)

Alternate version that accepts pre-allocated output buffer.

Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding. Safe here means that it does not use any non-compliant features beyond core JDK.

appendEncoded

public static int appendEncoded(byte[] input,
                int inputPtr,
                int inputLength,
                byte[] outputBuffer,
                int outputPtr,
                BufferRecycler bufferRecycler)

Alternate version that accepts pre-allocated output buffer.

Note that ChunkEncoder instance used is one produced by ChunkEncoderFactory.optimalNonAllocatingInstance(int), which typically is "unsafe" instance if one can be used on current JVM.

safeAppendEncoded

public static int safeAppendEncoded(byte[] input,
                    int inputPtr,
                    int inputLength,
                    byte[] outputBuffer,
                    int outputPtr,
                    BufferRecycler bufferRecycler)

Alternate version that accepts pre-allocated output buffer.

Method that will use "safe" ChunkEncoder, as produced by ChunkEncoderFactory.safeInstance(), for encoding. Safe here means that it does not use any non-compliant features beyond core JDK.

appendEncoded

public static int appendEncoded(ChunkEncoder enc,
                byte[] input,
                int inputPtr,
                int inputLength,
                byte[] outputBuffer,
                int outputPtr)

Alternate version that accepts pre-allocated output buffer.