HpackUtil.java — netty Source File

Source Code

/*
 * Copyright 2015 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.
 */

/*
 * Copyright 2014 Twitter, Inc.
 *
 * Licensed 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.http2;

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

final class HpackUtil {
    /**
     * Compare two {@link CharSequence} objects without leaking timing information.
     * <p>
     * The {@code int} return type is intentional and is designed to allow cascading of constant time operations:
     * <pre>
     *     String s1 = "foo";
     *     String s2 = "foo";
     *     String s3 = "foo";
     *     String s4 = "goo";
     *     boolean equals = (equalsConstantTime(s1, s2) & equalsConstantTime(s3, s4)) != 0;
     * </pre>
     * @param s1 the first value.
     * @param s2 the second value.
     * @return {@code 0} if not equal. {@code 1} if equal.
     */
    static int equalsConstantTime(CharSequence s1, CharSequence s2) {
        if (s1 instanceof AsciiString && s2 instanceof AsciiString) {
            if (s1.length() != s2.length()) {
                return 0;
            }
            AsciiString s1Ascii = (AsciiString) s1;
            AsciiString s2Ascii = (AsciiString) s2;
// ... (313 more lines)