FastLzFrameEncoder.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.MessageToByteEncoder;

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_TYPE_NON_COMPRESSED;
import static io.netty.handler.codec.compression.FastLz.BLOCK_WITHOUT_CHECKSUM;
import static io.netty.handler.codec.compression.FastLz.BLOCK_WITH_CHECKSUM;
import static io.netty.handler.codec.compression.FastLz.CHECKSUM_OFFSET;
import static io.netty.handler.codec.compression.FastLz.LEVEL_1;
import static io.netty.handler.codec.compression.FastLz.LEVEL_2;
import static io.netty.handler.codec.compression.FastLz.LEVEL_AUTO;
import static io.netty.handler.codec.compression.FastLz.MAGIC_NUMBER;
import static io.netty.handler.codec.compression.FastLz.MAX_CHUNK_LENGTH;
import static io.netty.handler.codec.compression.FastLz.MIN_LENGTH_TO_COMPRESSION;
import static io.netty.handler.codec.compression.FastLz.OPTIONS_OFFSET;
import static io.netty.handler.codec.compression.FastLz.calculateOutputBufferLength;
import static io.netty.handler.codec.compression.FastLz.compress;

/**
 * Compresses a {@link ByteBuf} using the FastLZ algorithm.
 *
 * See <a href="https://github.com/netty/netty/issues/2750">FastLZ format</a>.
 */
public class FastLzFrameEncoder extends MessageToByteEncoder<ByteBuf> {
    /**
     * Compression level.
     */
    private final int level;

    /**
     * Underlying checksum calculator in use.
     */
    private final ByteBufChecksum checksum;

    /**
     * Creates a FastLZ encoder without checksum calculator and with auto detection of compression level.
     */
    public FastLzFrameEncoder() {
        this(LEVEL_AUTO, null);
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