/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cassandra.io.compress;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import net.jpountz.lz4.LZ4Exception;
import net.jpountz.lz4.LZ4Factory;
public class LZ4Compressor implements ICompressor
{
private static final int INTEGER_BYTES = 4;
private static final LZ4Compressor instance = new LZ4Compressor();
public static LZ4Compressor create(Map<String, String> args)
{
return instance;
}
private final net.jpountz.lz4.LZ4Compressor compressor;
private final net.jpountz.lz4.LZ4Decompressor decompressor;
private LZ4Compressor()
{
final LZ4Factory lz4Factory = LZ4Factory.fastestInstance();
compressor = lz4Factory.fastCompressor();
decompressor = lz4Factory.decompressor();
}
public int initialCompressedBufferLength(int chunkLength)
{
return INTEGER_BYTES + compressor.maxCompressedLength(chunkLength);
}
public int compress(byte[] input, int inputOffset, int inputLength, WrappedArray output, int outputOffset) throws IOException
{
final byte[] dest = output.buffer;
dest[outputOffset] = (byte) inputLength;
dest[outputOffset + 1] = (byte) (inputLength >>> 8);
dest[outputOffset + 2] = (byte) (inputLength >>> 16);
dest[outputOffset + 3] = (byte) (inputLength >>> 24);
final int maxCompressedLength = compressor.maxCompressedLength(inputLength);
try
{
return INTEGER_BYTES + compressor.compress(input, inputOffset, inputLength,
dest, outputOffset + INTEGER_BYTES, maxCompressedLength);
}
catch (LZ4Exception e)
{
throw new IOException(e);
}
}
public int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset) throws IOException
{
final int decompressedLength =
(input[inputOffset] & 0xFF)
| ((input[inputOffset + 1] & 0xFF) << 8)
| ((input[inputOffset + 2] & 0xFF) << 16)
| ((input[inputOffset + 3] & 0xFF) << 24);
final int compressedLength;
try
{
compressedLength = decompressor.decompress(input, inputOffset + INTEGER_BYTES,
output, outputOffset, decompressedLength);
}
catch (LZ4Exception e)
{
throw new IOException(e);
}
if (compressedLength != inputLength - INTEGER_BYTES)
{
throw new IOException("Compressed lengths mismatch");
}
return decompressedLength;
}
public Set<String> supportedOptions()
{
return new HashSet<String>(Arrays.asList(CompressionParameters.CRC_CHECK_CHANCE));
}
}