QpackUtil.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.internal.ConstantTimeUtils;
import io.netty.util.internal.PlatformDependent;

import static io.netty.util.internal.ObjectUtil.checkInRange;
import static java.lang.Math.floorDiv;

final class QpackUtil {
    private static final QpackException PREFIXED_INTEGER_TOO_LONG =
            QpackException.newStatic(QpackDecoder.class, "toIntOrThrow(...)",
                    "QPACK - invalid prefixed integer");

    /**
     * Encode integer according to
     * <a href="https://tools.ietf.org/html/rfc7541#section-5.1">Section 5.1</a>.
     */
    static void encodePrefixedInteger(ByteBuf out, byte mask, int prefixLength, long toEncode) {
        checkInRange(toEncode, 0, MAX_UNSIGNED_INT, "toEncode");
        int nbits = (1 << prefixLength) - 1;
        if (toEncode < nbits) {
            out.writeByte((byte) (mask | toEncode));
        } else {
            out.writeByte((byte) (mask | nbits));
            long remainder = toEncode - nbits;
            while (remainder > 128) {
                byte next = (byte) ((remainder % 128) | 0x80);
                out.writeByte(next);
                remainder = remainder / 128;
            }
            out.writeByte((byte) remainder);
        }
    }

    /**
     * Decode the integer or return {@code -1} if not enough bytes are readable.
     * This method increases the readerIndex when the integer could be decoded.
     *
     * @param in the input {@link ByteBuf}
     * @param prefixLength the prefix length
     * @return the integer or {@code -1} if not enough readable bytes are in the {@link ByteBuf).
     */
    static int decodePrefixedIntegerAsInt(ByteBuf in, int prefixLength) throws QpackException {
// ... (409 more lines)