Bzip2HuffmanStageDecoder.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 static io.netty.handler.codec.compression.Bzip2Constants.HUFFMAN_DECODE_MAX_CODE_LENGTH;
import static io.netty.handler.codec.compression.Bzip2Constants.HUFFMAN_GROUP_RUN_LENGTH;
import static io.netty.handler.codec.compression.Bzip2Constants.HUFFMAN_MAX_ALPHABET_SIZE;

/**
 * A decoder for the Bzip2 Huffman coding stage.
 */
final class Bzip2HuffmanStageDecoder {
    /**
     * A reader that provides bit-level reads.
     */
    private final Bzip2BitReader reader;

    /**
     * The Huffman table number to use for each group of 50 symbols.
     */
    byte[] selectors;

    /**
     * The minimum code length for each Huffman table.
     */
    private final int[] minimumLengths;

    /**
     * An array of values for each Huffman table that must be subtracted from the numerical value of
     * a Huffman code of a given bit length to give its canonical code index.
     */
    private final int[][] codeBases;

    /**
     * An array of values for each Huffman table that gives the highest numerical value of a Huffman
     * code of a given bit length.
     */
    private final int[][] codeLimits;

    /**
     * A mapping for each Huffman table from canonical code index to output symbol.
     */
    private final int[][] codeSymbols;

    /**
     * The Huffman table for the current group.
     */
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