Java tutorial
/** * 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.pulsar.common.compression; import com.github.luben.zstd.Zstd; import io.netty.buffer.ByteBuf; import io.netty.buffer.PooledByteBufAllocator; import java.io.IOException; import java.nio.ByteBuffer; /** * Zstandard Compression */ public class CompressionCodecZstd implements CompressionCodec { private static final int ZSTD_COMPRESSION_LEVEL = 3; @Override public ByteBuf encode(ByteBuf source) { int uncompressedLength = source.readableBytes(); int maxLength = (int) Zstd.compressBound(uncompressedLength); ByteBuf target = PooledByteBufAllocator.DEFAULT.directBuffer(maxLength, maxLength); int compressedLength; if (source.hasMemoryAddress()) { compressedLength = (int) Zstd.compressUnsafe(target.memoryAddress(), maxLength, source.memoryAddress() + source.readerIndex(), uncompressedLength, ZSTD_COMPRESSION_LEVEL); } else { ByteBuffer sourceNio = source.nioBuffer(source.readerIndex(), source.readableBytes()); ByteBuffer targetNio = target.nioBuffer(0, maxLength); compressedLength = Zstd.compress(targetNio, sourceNio, ZSTD_COMPRESSION_LEVEL); } target.writerIndex(compressedLength); return target; } @Override public ByteBuf decode(ByteBuf encoded, int uncompressedLength) throws IOException { ByteBuf uncompressed = PooledByteBufAllocator.DEFAULT.directBuffer(uncompressedLength, uncompressedLength); if (encoded.hasMemoryAddress()) { Zstd.decompressUnsafe(uncompressed.memoryAddress(), uncompressedLength, encoded.memoryAddress() + encoded.readerIndex(), encoded.readableBytes()); } else { ByteBuffer uncompressedNio = uncompressed.nioBuffer(0, uncompressedLength); ByteBuffer encodedNio = encoded.nioBuffer(encoded.readerIndex(), encoded.readableBytes()); Zstd.decompress(uncompressedNio, encodedNio); } uncompressed.writerIndex(uncompressedLength); return uncompressed; } }