AsciiStringUtil.java — netty Source File

Source Code

/*
 * Copyright 2024 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.util;

import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.SWARUtil;

/**
 * A collection of utility methods that is related with handling {@link AsciiString}.
 */
final class AsciiStringUtil {

    /**
     * Convert the {@link AsciiString} to a lower case.
     *
     * @param string the {@link AsciiString} to convert
     * @return the new {@link AsciiString} in lower case
     */
    static AsciiString toLowerCase(final AsciiString string) {
        final byte[] byteArray = string.array();
        final int offset = string.arrayOffset();
        final int length = string.length();
        if (!containsUpperCase(byteArray, offset, length)) {
            return string;
        }
        final byte[] newByteArray = PlatformDependent.allocateUninitializedArray(length);
        toLowerCase(byteArray, offset, newByteArray);
        return new AsciiString(newByteArray, false);
    }

    private static boolean containsUpperCase(final byte[] byteArray, int offset, final int length) {
        if (!PlatformDependent.isUnaligned()) {
            return linearContainsUpperCase(byteArray, offset, length);
        }

        final int longCount = length >>> 3;
        for (int i = 0; i < longCount; ++i) {
            final long word = PlatformDependent.getLong(byteArray, offset);
            if (SWARUtil.containsUpperCase(word)) {
                return true;
            }
            offset += Long.BYTES;
        }
        return unrolledContainsUpperCase(byteArray, offset, length & 7);
    }

    private static boolean linearContainsUpperCase(final byte[] byteArray, final int offset, final int length) {
// ... (232 more lines)