LzmaFrameEncoder.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.buffer.ByteBufInputStream;
import io.netty.buffer.ByteBufOutputStream;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import lzma.sdk.lzma.Base;
import lzma.sdk.lzma.Encoder;

import java.io.InputStream;

import static lzma.sdk.lzma.Encoder.EMatchFinderTypeBT4;

/**
 * Compresses a {@link ByteBuf} using the LZMA algorithm.
 *
 * See <a href="https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Markov_chain_algorithm">LZMA</a>
 * and <a href="https://svn.python.org/projects/external/xz-5.0.5/doc/lzma-file-format.txt">LZMA format</a>
 * or documents in <a href="https://www.7-zip.org/sdk.html">LZMA SDK</a> archive.
 */
public class LzmaFrameEncoder extends MessageToByteEncoder<ByteBuf> {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(LzmaFrameEncoder.class);

    private static final int MEDIUM_DICTIONARY_SIZE = 1 << 16;

    private static final int MIN_FAST_BYTES = 5;
    private static final int MEDIUM_FAST_BYTES = 0x20;
    private static final int MAX_FAST_BYTES = Base.kMatchMaxLen;

    private static final int DEFAULT_MATCH_FINDER = EMatchFinderTypeBT4;

    private static final int DEFAULT_LC = 3;
    private static final int DEFAULT_LP = 0;
    private static final int DEFAULT_PB = 2;

    /**
     * Underlying LZMA encoder in use.
     */
    private final Encoder encoder;

    /**
// ... (154 more lines)