QpackHuffmanEncoder.java — netty Source File

Source Code

/*
 * Copyright 2020 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.http3;

import io.netty.buffer.ByteBuf;
import io.netty.util.AsciiString;
import io.netty.util.ByteProcessor;
import io.netty.util.internal.ObjectUtil;

final class QpackHuffmanEncoder {

    private final int[] codes;
    private final byte[] lengths;
    private final EncodedLengthProcessor encodedLengthProcessor = new EncodedLengthProcessor();
    private final EncodeProcessor encodeProcessor = new EncodeProcessor();

    QpackHuffmanEncoder() {
        this(QpackUtil.HUFFMAN_CODES, QpackUtil.HUFFMAN_CODE_LENGTHS);
    }

    /**
     * Creates a new Huffman encoder with the specified Huffman coding.
     *
     * @param codes the Huffman codes indexed by symbol
     * @param lengths the length of each Huffman code
     */
    private QpackHuffmanEncoder(int[] codes, byte[] lengths) {
        this.codes = codes;
        this.lengths = lengths;
    }

    /**
     * Compresses the input string literal using the Huffman coding.
     *
     * @param out the output stream for the compressed data
     * @param data the string literal to be Huffman encoded
     */
    public void encode(ByteBuf out, CharSequence data) {
        ObjectUtil.checkNotNull(out, "out");
        if (data instanceof AsciiString) {
            AsciiString string = (AsciiString) data;
            try {
                encodeProcessor.out = out;
                string.forEachByte(encodeProcessor);
            } catch (Exception e) {
                throw new IllegalStateException(e);
            } finally {
// ... (117 more lines)