AsciiString.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.util;

import io.netty.util.internal.EmptyArrays;
import io.netty.util.internal.InternalThreadLocalMap;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.PlatformDependent;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import static io.netty.util.internal.MathUtil.isOutOfBounds;
import static io.netty.util.internal.ObjectUtil.checkNotNull;

/**
 * A string which has been encoded into a character encoding whose character always takes a single byte, similarly to
 * ASCII. It internally keeps its content in a byte array unlike {@link String}, which uses a character array, for
 * reduced memory footprint and faster data transfer from/to byte-based data structures such as a byte array and
 * {@link ByteBuffer}. It is often used in conjunction with {@code Headers} that require a {@link CharSequence}.
 * <p>
 * This class was designed to provide an immutable array of bytes, and caches some internal state based upon the value
 * of this array. However underlying access to this byte array is provided via not copying the array on construction or
 * {@link #array()}. If any changes are made to the underlying byte array it is the user's responsibility to call
 * {@link #arrayChanged()} so the state of this class can be reset.
 */
public final class AsciiString implements CharSequence, Comparable<CharSequence> {
    public static final AsciiString EMPTY_STRING = cached("");
    private static final char MAX_CHAR_VALUE = 255;

    public static final int INDEX_NOT_FOUND = -1;

    /**
     * If this value is modified outside the constructor then call {@link #arrayChanged()}.
     */
    private final byte[] value;
    /**
     * Offset into {@link #value} that all operations should use when acting upon {@link #value}.
     */
    private final int offset;
// ... (1794 more lines)