org.apache.lucene.util.compress

Class LZ4

java.lang.Object

org.apache.lucene.util.compress.LZ4

public final class LZ4
extends Object

LZ4 compression and decompression routines. https://github.com/lz4/lz4/tree/dev/lib http://fastcompression.blogspot.fr/p/lz4.html The high-compression option is a simpler version of the one of the original algorithm, and only retains a better hash table that remembers about more occurrences of a previous 4-bytes sequence, and removes all the logic about handling of the case when overlapping matches are found.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LZ4.FastCompressionHashTable Simple lossy HashTable that only stores the last ocurrence for each hash on 2^14 bytes of memory.
static class	LZ4.HighCompressionHashTable A higher-precision HashTable.

Method Summary

Modifier and Type	Method and Description
static void	compress(byte[] bytes, int off, int len, DataOutput out, org.apache.lucene.util.compress.LZ4.HashTable ht) Compress bytes[off:off+len] into out using at most 16KB of memory.
static int	decompress(DataInput compressed, int decompressedLen, byte[] dest) Decompress at least decompressedLen bytes into dest[dOff:].

Methods inherited from class java.lang.Object

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

Method Detail

decompress

public static int decompress(DataInput compressed,
                             int decompressedLen,
                             byte[] dest)
                      throws IOException

Decompress at least decompressedLen bytes into dest[dOff:]. Please note that dest must be large enough to be able to hold all decompressed data (meaning that you need to know the total decompressed length).

Throws:

IOException

compress

public static void compress(byte[] bytes,
                            int off,
                            int len,
                            DataOutput out,
                            org.apache.lucene.util.compress.LZ4.HashTable ht)
                     throws IOException

Compress bytes[off:off+len] into out using at most 16KB of memory. ht shouldn't be shared across threads but can safely be reused.

Throws:

IOException