shade.io.netty.handler.codec.compression.FastLzFrameDecoder Maven / Gradle / Ivy
/*
* 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 java.util.List;
import java.util.zip.Adler32;
import java.util.zip.Checksum;
import static io.netty.handler.codec.compression.FastLz.BLOCK_TYPE_COMPRESSED;
import static io.netty.handler.codec.compression.FastLz.BLOCK_WITH_CHECKSUM;
import static io.netty.handler.codec.compression.FastLz.MAGIC_NUMBER;
import static io.netty.handler.codec.compression.FastLz.decompress;
/**
* Uncompresses a {@link ByteBuf} encoded by {@link FastLzFrameEncoder} using the FastLZ algorithm.
*
* See FastLZ format.
*/
public class FastLzFrameDecoder extends ByteToMessageDecoder {
/**
* Current state of decompression.
*/
private enum State {
INIT_BLOCK,
INIT_BLOCK_PARAMS,
DECOMPRESS_DATA,
CORRUPTED
}
private State currentState = State.INIT_BLOCK;
/**
* Underlying checksum calculator in use.
*/
private final ByteBufChecksum checksum;
/**
* Length of current received chunk of data.
*/
private int chunkLength;
/**
* Original of current received chunk of data.
* It is equal to {@link #chunkLength} for non compressed chunks.
*/
private int originalLength;
/**
* Indicates is this chunk compressed or not.
*/
private boolean isCompressed;
/**
* Indicates is this chunk has checksum or not.
*/
private boolean hasChecksum;
/**
* Checksum value of current received chunk of data which has checksum.
*/
private int currentChecksum;
/**
* Creates the fastest FastLZ decoder without checksum calculation.
*/
public FastLzFrameDecoder() {
this(false);
}
/**
* Creates a FastLZ decoder with calculation of checksums as specified.
*
* @param validateChecksums
* If true, the checksum field will be validated against the actual
* uncompressed data, and if the checksums do not match, a suitable
* {@link DecompressionException} will be thrown.
* Note, that in this case decoder will use {@link java.util.zip.Adler32}
* as a default checksum calculator.
*/
public FastLzFrameDecoder(boolean validateChecksums) {
this(validateChecksums ? new Adler32() : null);
}
/**
* Creates a FastLZ decoder with specified checksum calculator.
*
* @param checksum
* the {@link Checksum} instance to use to check data for integrity.
* You may set {@code null} if you do not want to validate checksum of each block.
*/
public FastLzFrameDecoder(Checksum checksum) {
this.checksum = checksum == null ? null : ByteBufChecksum.wrapChecksum(checksum);
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List