Bzip2BlockCompressor.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.util.ByteProcessor;

import static io.netty.handler.codec.compression.Bzip2Constants.BLOCK_HEADER_MAGIC_1;
import static io.netty.handler.codec.compression.Bzip2Constants.BLOCK_HEADER_MAGIC_2;
import static io.netty.handler.codec.compression.Bzip2Constants.HUFFMAN_SYMBOL_RANGE_SIZE;

/**
 * Compresses and writes a single Bzip2 block.<br><br>
 *
 * Block encoding consists of the following stages:<br>
 * 1. Run-Length Encoding[1] - {@link #write(int)}<br>
 * 2. Burrows Wheeler Transform - {@link #close(ByteBuf)} (through {@link Bzip2DivSufSort})<br>
 * 3. Write block header - {@link #close(ByteBuf)}<br>
 * 4. Move To Front Transform - {@link #close(ByteBuf)} (through {@link Bzip2HuffmanStageEncoder})<br>
 * 5. Run-Length Encoding[2] - {@link #close(ByteBuf)}  (through {@link Bzip2HuffmanStageEncoder})<br>
 * 6. Create and write Huffman tables - {@link #close(ByteBuf)} (through {@link Bzip2HuffmanStageEncoder})<br>
 * 7. Huffman encode and write data - {@link #close(ByteBuf)} (through {@link Bzip2HuffmanStageEncoder})
 */
final class Bzip2BlockCompressor {
    private final ByteProcessor writeProcessor = new ByteProcessor() {
        @Override
        public boolean process(byte value) throws Exception {
            return write(value);
        }
    };

    /**
     * A writer that provides bit-level writes.
     */
    private final Bzip2BitWriter writer;

    /**
     * CRC builder for the block.
     */
    private final Crc32 crc = new Crc32();

    /**
     * The RLE'd block data.
     */
    private final byte[] block;

    /**
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