| /** |
| * 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.distributedlog.io; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import io.netty.buffer.ByteBuf; |
| import io.netty.buffer.PooledByteBufAllocator; |
| import java.nio.ByteBuffer; |
| import net.jpountz.lz4.LZ4Compressor; |
| import net.jpountz.lz4.LZ4Factory; |
| import net.jpountz.lz4.LZ4FastDecompressor; |
| |
| /** |
| * An {@code lz4} based {@link CompressionCodec} implementation. |
| * |
| * <p>All functions are thread safe. |
| */ |
| public class LZ4CompressionCodec implements CompressionCodec { |
| |
| public static LZ4CompressionCodec of() { |
| return INSTANCE; |
| } |
| |
| private static final LZ4CompressionCodec INSTANCE = new LZ4CompressionCodec(); |
| |
| private static final LZ4Factory factory = LZ4Factory.fastestJavaInstance(); |
| // Used for compression |
| private static final LZ4Compressor compressor = factory.fastCompressor(); |
| // Used to decompress when the size of the output is known |
| private static final LZ4FastDecompressor decompressor = factory.fastDecompressor(); |
| |
| @Override |
| public ByteBuf compress(ByteBuf uncompressed, int headerLen) { |
| checkNotNull(uncompressed); |
| checkArgument(uncompressed.readableBytes() > 0); |
| |
| int uncompressedLen = uncompressed.readableBytes(); |
| int maxLen = compressor.maxCompressedLength(uncompressedLen); |
| |
| // get the source bytebuffer |
| ByteBuffer uncompressedNio = uncompressed.nioBuffer(uncompressed.readerIndex(), uncompressedLen); |
| ByteBuf compressed = PooledByteBufAllocator.DEFAULT.buffer( |
| maxLen + headerLen, maxLen + headerLen); |
| ByteBuffer compressedNio = compressed.nioBuffer(headerLen, maxLen); |
| |
| int compressedLen = compressor.compress( |
| uncompressedNio, uncompressedNio.position(), uncompressedLen, |
| compressedNio, compressedNio.position(), maxLen); |
| compressed.writerIndex(compressedLen + headerLen); |
| |
| return compressed; |
| } |
| |
| @Override |
| // length parameter is ignored here because of the way the fastDecompressor works. |
| public ByteBuf decompress(ByteBuf compressed, int decompressedSize) { |
| checkNotNull(compressed); |
| checkArgument(compressed.readableBytes() >= 0); |
| checkArgument(decompressedSize >= 0); |
| |
| ByteBuf uncompressed = PooledByteBufAllocator.DEFAULT.buffer(decompressedSize, decompressedSize); |
| ByteBuffer uncompressedNio = uncompressed.nioBuffer(0, decompressedSize); |
| ByteBuffer compressedNio = compressed.nioBuffer(compressed.readerIndex(), compressed.readableBytes()); |
| |
| decompressor.decompress( |
| compressedNio, compressedNio.position(), |
| uncompressedNio, uncompressedNio.position(), uncompressedNio.remaining()); |
| uncompressed.writerIndex(decompressedSize); |
| return uncompressed; |
| } |
| } |