net.jpountz.lz4

Class LZ4SafeDecompressor

java.lang.Object

net.jpountz.lz4.LZ4SafeDecompressor

All Implemented Interfaces:

LZ4UnknownSizeDecompressor

public abstract class LZ4SafeDecompressor
extends java.lang.Object
implements LZ4UnknownSizeDecompressor

LZ4 decompressor that requires the size of the compressed data to be known.

Implementations of this class are usually a little slower than those of LZ4FastDecompressor but do not require the size of the original data to be known.

Constructor Summary

Constructors

Constructor and Description
LZ4SafeDecompressor()

Method Summary

Modifier and Type	Method and Description
int	decompress(byte[] src, byte[] dest) Convenience method, equivalent to calling decompress(src, 0, src.length, dest, 0)
byte[]	decompress(byte[] src, int maxDestLen) Convenience method, equivalent to calling decompress(src, 0, src.length, maxDestLen).
int	decompress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff) Convenience method, equivalent to calling decompress(src, srcOff, srcLen, dest, destOff, dest.length - destOff).
abstract int	decompress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff, int maxDestLen) Decompresses src[srcOff:srcOff+srcLen] into dest[destOff:destOff+maxDestLen] and returns the number of decompressed bytes written into dest.
byte[]	decompress(byte[] src, int srcOff, int srcLen, int maxDestLen) Convenience method which returns src[srcOff:srcOff+srcLen] decompressed.
void	decompress(java.nio.ByteBuffer src, java.nio.ByteBuffer dest) Decompresses src into dest.
abstract int	decompress(java.nio.ByteBuffer src, int srcOff, int srcLen, java.nio.ByteBuffer dest, int destOff, int maxDestLen) Decompresses src[srcOff:srcOff+srcLen] into dest[destOff:destOff+maxDestLen] and returns the number of decompressed bytes written into dest.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

LZ4SafeDecompressor

public LZ4SafeDecompressor()

Method Detail

decompress

public abstract int decompress(byte[] src,
                               int srcOff,
                               int srcLen,
                               byte[] dest,
                               int destOff,
                               int maxDestLen)

Decompresses src[srcOff:srcOff+srcLen] into dest[destOff:destOff+maxDestLen] and returns the number of decompressed bytes written into dest.

Specified by:

decompress in interface LZ4UnknownSizeDecompressor

Parameters:

src - the compressed data

srcOff - the start offset in src

srcLen - the exact size of the compressed data

dest - the destination buffer to store the decompressed data

destOff - the start offset in dest

maxDestLen - the maximum number of bytes to write in dest

Returns:

the original input size

Throws:

LZ4Exception - if maxDestLen is too small

decompress

public abstract int decompress(java.nio.ByteBuffer src,
                               int srcOff,
                               int srcLen,
                               java.nio.ByteBuffer dest,
                               int destOff,
                               int maxDestLen)

Decompresses src[srcOff:srcOff+srcLen] into dest[destOff:destOff+maxDestLen] and returns the number of decompressed bytes written into dest. The positions and limits of the ByteBuffers remain unchanged.

Parameters:

src - the compressed data

srcOff - the start offset in src

srcLen - the exact size of the compressed data

dest - the destination buffer to store the decompressed data

destOff - the start offset in dest

maxDestLen - the maximum number of bytes to write in dest

Returns:

the original input size

Throws:

LZ4Exception - if maxDestLen is too small

decompress

public final int decompress(byte[] src,
                            int srcOff,
                            int srcLen,
                            byte[] dest,
                            int destOff)

Convenience method, equivalent to calling decompress(src, srcOff, srcLen, dest, destOff, dest.length - destOff).

Specified by:

decompress in interface LZ4UnknownSizeDecompressor

Parameters:

src - the compressed data

srcOff - the start offset in src

srcLen - the exact size of the compressed data

dest - the destination buffer to store the decompressed data

destOff - the start offset in dest

Returns:

the original input size

Throws:

LZ4Exception - if dest is too small

decompress

public final int decompress(byte[] src,
                            byte[] dest)

Convenience method, equivalent to calling decompress(src, 0, src.length, dest, 0)

Parameters:

src - the compressed data

dest - the destination buffer to store the decompressed data

Returns:

the original input size

Throws:

LZ4Exception - if dest is too small

decompress

public final byte[] decompress(byte[] src,
                               int srcOff,
                               int srcLen,
                               int maxDestLen)

Convenience method which returns src[srcOff:srcOff+srcLen] decompressed.

Warning: this method has an important overhead due to the fact that it needs to allocate a buffer to decompress into, and then needs to resize this buffer to the actual decompressed length.

Here is how this method is implemented:

 byte[] decompressed = new byte[maxDestLen];
 final int decompressedLength = decompress(src, srcOff, srcLen, decompressed, 0, maxDestLen);
 if (decompressedLength != decompressed.length) {
   decompressed = Arrays.copyOf(decompressed, decompressedLength);
 }
 return decompressed;
 

Parameters:

src - the compressed data

srcOff - the start offset in src

srcLen - the exact size of the compressed data

maxDestLen - the maximum number of bytes to write in dest

Returns:

the decompressed data

Throws:

LZ4Exception - if maxDestLen is too small

decompress

public final byte[] decompress(byte[] src,
                               int maxDestLen)

Convenience method, equivalent to calling decompress(src, 0, src.length, maxDestLen).

Parameters:

src - the compressed data

maxDestLen - the maximum number of bytes to write in dest

Returns:

the decompressed data

Throws:

LZ4Exception - if maxDestLen is too small

decompress

public final void decompress(java.nio.ByteBuffer src,
                             java.nio.ByteBuffer dest)

Decompresses src into dest. src's Buffer.remaining() must be exactly the size of the compressed data. This method moves the positions of the buffers.

Parameters:

src - the compressed data

dest - the destination buffer to store the decompressed data

Throws:

LZ4Exception - if dest is too small

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object