| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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 |
| * |
| * http://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 org.apache.kafka.common.utils; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| |
| /** |
| * Utility class that handles immutable byte arrays. |
| */ |
| public class Bytes implements Comparable<Bytes> { |
| |
| public static final byte[] EMPTY = new byte[0]; |
| |
| private static final char[] HEX_CHARS_UPPER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; |
| |
| private final byte[] bytes; |
| |
| // cache the hash code for the string, default to 0 |
| private int hashCode; |
| |
| public static Bytes wrap(byte[] bytes) { |
| if (bytes == null) |
| return null; |
| return new Bytes(bytes); |
| } |
| |
| /** |
| * Create a Bytes using the byte array. |
| * |
| * @param bytes This array becomes the backing storage for the object. |
| */ |
| public Bytes(byte[] bytes) { |
| this.bytes = bytes; |
| |
| // initialize hash code to 0 |
| hashCode = 0; |
| } |
| |
| /** |
| * Get the data from the Bytes. |
| * @return The underlying byte array |
| */ |
| public byte[] get() { |
| return this.bytes; |
| } |
| |
| /** |
| * The hashcode is cached except for the case where it is computed as 0, in which |
| * case we compute the hashcode on every call. |
| * |
| * @return the hashcode |
| */ |
| @Override |
| public int hashCode() { |
| if (hashCode == 0) { |
| hashCode = Arrays.hashCode(bytes); |
| } |
| |
| return hashCode; |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (this == other) |
| return true; |
| if (other == null) |
| return false; |
| |
| // we intentionally use the function to compute hashcode here |
| if (this.hashCode() != other.hashCode()) |
| return false; |
| |
| if (other instanceof Bytes) |
| return Arrays.equals(this.bytes, ((Bytes) other).get()); |
| |
| return false; |
| } |
| |
| @Override |
| public int compareTo(Bytes that) { |
| return BYTES_LEXICO_COMPARATOR.compare(this.bytes, that.bytes); |
| } |
| |
| @Override |
| public String toString() { |
| return Bytes.toString(bytes, 0, bytes.length); |
| } |
| |
| /** |
| * Write a printable representation of a byte array. Non-printable |
| * characters are hex escaped in the format \\x%02X, eg: |
| * \x00 \x05 etc. |
| * |
| * This function is brought from org.apache.hadoop.hbase.util.Bytes |
| * |
| * @param b array to write out |
| * @param off offset to start at |
| * @param len length to write |
| * @return string output |
| */ |
| private static String toString(final byte[] b, int off, int len) { |
| StringBuilder result = new StringBuilder(); |
| |
| if (b == null) |
| return result.toString(); |
| |
| // just in case we are passed a 'len' that is > buffer length... |
| if (off >= b.length) |
| return result.toString(); |
| |
| if (off + len > b.length) |
| len = b.length - off; |
| |
| for (int i = off; i < off + len; ++i) { |
| int ch = b[i] & 0xFF; |
| if (ch >= ' ' && ch <= '~' && ch != '\\') { |
| result.append((char) ch); |
| } else { |
| result.append("\\x"); |
| result.append(HEX_CHARS_UPPER[ch / 0x10]); |
| result.append(HEX_CHARS_UPPER[ch % 0x10]); |
| } |
| } |
| return result.toString(); |
| } |
| |
| /** |
| * A byte array comparator based on lexicograpic ordering. |
| */ |
| public final static ByteArrayComparator BYTES_LEXICO_COMPARATOR = new LexicographicByteArrayComparator(); |
| |
| public interface ByteArrayComparator extends Comparator<byte[]>, Serializable { |
| |
| int compare(final byte[] buffer1, int offset1, int length1, |
| final byte[] buffer2, int offset2, int length2); |
| } |
| |
| private static class LexicographicByteArrayComparator implements ByteArrayComparator { |
| |
| @Override |
| public int compare(byte[] buffer1, byte[] buffer2) { |
| return compare(buffer1, 0, buffer1.length, buffer2, 0, buffer2.length); |
| } |
| |
| public int compare(final byte[] buffer1, int offset1, int length1, |
| final byte[] buffer2, int offset2, int length2) { |
| |
| // short circuit equal case |
| if (buffer1 == buffer2 && |
| offset1 == offset2 && |
| length1 == length2) { |
| return 0; |
| } |
| |
| // similar to Arrays.compare() but considers offset and length |
| int end1 = offset1 + length1; |
| int end2 = offset2 + length2; |
| for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) { |
| int a = buffer1[i] & 0xff; |
| int b = buffer2[j] & 0xff; |
| if (a != b) { |
| return a - b; |
| } |
| } |
| return length1 - length2; |
| } |
| } |
| } |