Lz4FrameDecoder.java — netty Source File

Source Code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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 io.netty.handler.codec.compression;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.util.internal.ObjectUtil;
import net.jpountz.lz4.LZ4Exception;
import net.jpountz.lz4.LZ4Factory;
import net.jpountz.lz4.LZ4FastDecompressor;

import java.util.List;
import java.util.zip.Checksum;

import static io.netty.handler.codec.compression.Lz4Constants.BLOCK_TYPE_COMPRESSED;
import static io.netty.handler.codec.compression.Lz4Constants.BLOCK_TYPE_NON_COMPRESSED;
import static io.netty.handler.codec.compression.Lz4Constants.COMPRESSION_LEVEL_BASE;
import static io.netty.handler.codec.compression.Lz4Constants.DEFAULT_SEED;
import static io.netty.handler.codec.compression.Lz4Constants.HEADER_LENGTH;
import static io.netty.handler.codec.compression.Lz4Constants.MAGIC_NUMBER;
import static io.netty.handler.codec.compression.Lz4Constants.MAX_BLOCK_SIZE;

/**
 * Uncompresses a {@link ByteBuf} encoded with the LZ4 format.
 *
 * See original <a href="https://github.com/Cyan4973/lz4">LZ4 Github project</a>
 * and <a href="https://fastcompression.blogspot.ru/2011/05/lz4-explained.html">LZ4 block format</a>
 * for full description.
 *
 * Since the original LZ4 block format does not contains size of compressed block and size of original data
 * this encoder uses format like <a href="https://github.com/idelpivnitskiy/lz4-java">LZ4 Java</a> library
 * written by Adrien Grand and approved by Yann Collet (author of original LZ4 library).
 *
 *  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *     * * * * * * * * * *
 *  * Magic * Token *  Compressed *  Decompressed *  Checksum *  +  *  LZ4 compressed *
 *  *       *       *    length   *     length    *           *     *      block      *
 *  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *     * * * * * * * * * *
 */
public class Lz4FrameDecoder extends ByteToMessageDecoder {
    /**
     * Current state of stream.
     */
    private enum State {
        INIT_BLOCK,
        DECOMPRESS_DATA,
        FINISHED,
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