CompressionCodecLZ4.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * Licensed 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 com.yahoo.pulsar.common.compression;

import java.io.IOException;
import java.nio.ByteBuffer;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.PooledByteBufAllocator;
import net.jpountz.lz4.LZ4Compressor;
import net.jpountz.lz4.LZ4Factory;
import net.jpountz.lz4.LZ4FastDecompressor;

/**
 * LZ4 Compression
 */
public class CompressionCodecLZ4 implements CompressionCodec {

    private static final LZ4Factory lz4Factory = LZ4Factory.fastestInstance();
    private static final LZ4Compressor compressor = lz4Factory.fastCompressor();
    private static final LZ4FastDecompressor decompressor = lz4Factory.fastDecompressor();

    @Override
    public ByteBuf encode(ByteBuf source) {
        int uncompressedLength = source.readableBytes();
        int maxLength = compressor.maxCompressedLength(uncompressedLength);

        ByteBuffer sourceNio = source.nioBuffer(source.readerIndex(), source.readableBytes());

        ByteBuf target = PooledByteBufAllocator.DEFAULT.buffer(maxLength, maxLength);
        ByteBuffer targetNio = target.nioBuffer(0, maxLength);

        int compressedLength = compressor.compress(sourceNio, 0, uncompressedLength, targetNio, 0, maxLength);
        target.writerIndex(compressedLength);
        return target;
    }

    @Override
    public ByteBuf decode(ByteBuf encoded, int uncompressedLength) throws IOException {
        ByteBuf uncompressed = PooledByteBufAllocator.DEFAULT.buffer(uncompressedLength, uncompressedLength);
        ByteBuffer uncompressedNio = uncompressed.nioBuffer(0, uncompressedLength);

        ByteBuffer encodedNio = encoded.nioBuffer(encoded.readerIndex(), encoded.readableBytes());
        decompressor.decompress(encodedNio, encodedNio.position(), uncompressedNio, uncompressedNio.position(),
                uncompressedNio.remaining());

        uncompressed.writerIndex(uncompressedLength);
        return uncompressed;
    }
}