813 lines
25 KiB
Java
813 lines
25 KiB
Java
/*
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* MIT License
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*
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* Copyright (c) 2020-2023 Fabio Lima
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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package com.github.f4b6a3.ulid;
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import java.io.Serializable;
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import java.time.Instant;
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import java.util.Arrays;
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import java.util.UUID;
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import java.util.concurrent.ThreadLocalRandom;
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/**
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* A class that represents ULIDs.
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* <p>
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* ULID is a 128-bit value that has two components:
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* <ul>
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* <li><b>Time component</b>: a number of milliseconds since 1970-01-01 (Unix
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* epoch).
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* <li><b>Random component</b>: a sequence of 80 random bits generated by a
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* secure random generator.
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* </ul>
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* <p>
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* ULID has 128-bit compatibility with {@link UUID}. Like a UUID, a ULID can
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* also be stored as a 16-byte array.
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* <p>
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* Instances of this class are <b>immutable</b>.
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*
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* @see <a href="https://github.com/ulid/spec">ULID Specification</a>
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*/
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public final class Ulid implements Serializable, Comparable<Ulid> {
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private static final long serialVersionUID = 2625269413446854731L;
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private final long msb; // most significant bits
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private final long lsb; // least significant bits
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/**
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* Number of characters of a ULID.
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*/
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public static final int ULID_CHARS = 26;
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/**
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* Number of characters of the time component of a ULID.
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*/
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public static final int TIME_CHARS = 10;
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/**
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* Number of characters of the random component of a ULID.
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*/
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public static final int RANDOM_CHARS = 16;
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/**
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* Number of bytes of a ULID.
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*/
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public static final int ULID_BYTES = 16;
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/**
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* Number of bytes of the time component of a ULID.
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*/
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public static final int TIME_BYTES = 6;
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/**
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* Number of bytes of the random component of a ULID.
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*/
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public static final int RANDOM_BYTES = 10;
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/**
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* A special ULID that has all 128 bits set to ZERO.
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*/
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public static final Ulid MIN = new Ulid(0x0000000000000000L, 0x0000000000000000L);
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/**
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* A special ULID that has all 128 bits set to ONE.
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*/
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public static final Ulid MAX = new Ulid(0xffffffffffffffffL, 0xffffffffffffffffL);
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static final byte[] ALPHABET_VALUES = new byte[256];
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static final char[] ALPHABET_UPPERCASE = "0123456789ABCDEFGHJKMNPQRSTVWXYZ".toCharArray();
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static final char[] ALPHABET_LOWERCASE = "0123456789abcdefghjkmnpqrstvwxyz".toCharArray();
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static {
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// Initialize the alphabet map with -1
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Arrays.fill(ALPHABET_VALUES, (byte) -1);
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// Map the alphabets chars to values
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for (int i = 0; i < ALPHABET_UPPERCASE.length; i++) {
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ALPHABET_VALUES[ALPHABET_UPPERCASE[i]] = (byte) i;
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}
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for (int i = 0; i < ALPHABET_LOWERCASE.length; i++) {
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ALPHABET_VALUES[ALPHABET_LOWERCASE[i]] = (byte) i;
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}
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// Upper case OIL
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ALPHABET_VALUES['O'] = 0x00;
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ALPHABET_VALUES['I'] = 0x01;
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ALPHABET_VALUES['L'] = 0x01;
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// Lower case OIL
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ALPHABET_VALUES['o'] = 0x00;
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ALPHABET_VALUES['i'] = 0x01;
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ALPHABET_VALUES['l'] = 0x01;
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}
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// 0xffffffffffffffffL + 1 = 0x0000000000000000L
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private static final long INCREMENT_OVERFLOW = 0x0000000000000000L;
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/**
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* Creates a new ULID.
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* <p>
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* Useful to make copies of ULIDs.
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*
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* @param ulid a ULID
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*/
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public Ulid(Ulid ulid) {
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this.msb = ulid.msb;
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this.lsb = ulid.lsb;
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}
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/**
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* Creates a new ULID.
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* <p>
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* If you want to make a copy of a {@link UUID}, use {@link Ulid#from(UUID)}
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* instead.
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*
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* @param mostSignificantBits the first 8 bytes as a long value
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* @param leastSignificantBits the last 8 bytes as a long value
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*/
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public Ulid(long mostSignificantBits, long leastSignificantBits) {
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this.msb = mostSignificantBits;
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this.lsb = leastSignificantBits;
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}
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/**
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* Creates a new ULID.
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* <p>
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* Time parameter is the number of milliseconds since 1970-01-01 (Unix epoch).
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* It must be a positive number not larger than 2^48-1.
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* <p>
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* Random parameter must be an array of 10 bytes.
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*
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* @param time the number of milliseconds since 1970-01-01
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* @param random an array of 10 bytes
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* @throws IllegalArgumentException if time is negative or larger than 2^48-1
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* @throws IllegalArgumentException if random is null or its length is not 10
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*/
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public Ulid(long time, byte[] random) {
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// The time component has 48 bits.
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if ((time & 0xffff000000000000L) != 0) {
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// ULID specification:
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// "Any attempt to decode or encode a ULID larger than this (time > 2^48-1)
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// should be rejected by all implementations, to prevent overflow bugs."
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throw new IllegalArgumentException("Invalid time value"); // overflow or negative time!
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}
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// The random component has 80 bits (10 bytes).
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if (random == null || random.length != RANDOM_BYTES) {
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throw new IllegalArgumentException("Invalid random bytes"); // null or wrong length!
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}
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long long0 = 0;
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long long1 = 0;
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long0 |= time << 16;
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long0 |= (long) (random[0x0] & 0xff) << 8;
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long0 |= (long) (random[0x1] & 0xff);
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long1 |= (long) (random[0x2] & 0xff) << 56;
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long1 |= (long) (random[0x3] & 0xff) << 48;
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long1 |= (long) (random[0x4] & 0xff) << 40;
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long1 |= (long) (random[0x5] & 0xff) << 32;
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long1 |= (long) (random[0x6] & 0xff) << 24;
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long1 |= (long) (random[0x7] & 0xff) << 16;
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long1 |= (long) (random[0x8] & 0xff) << 8;
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long1 |= (long) (random[0x9] & 0xff);
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this.msb = long0;
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this.lsb = long1;
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}
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/**
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* Returns a fast new ULID.
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* <p>
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* This static method is a quick alternative to {@link UlidCreator#getUlid()}.
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* <p>
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* It employs {@link ThreadLocalRandom} which works very well, although not
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* cryptographically strong. It can be useful, for example, for logging.
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* <p>
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* Security-sensitive applications that require a cryptographically secure
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* pseudo-random generator should use {@link UlidCreator#getUlid()}.
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*
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* @return a ULID
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* @see {@link ThreadLocalRandom}
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* @since 5.1.0
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*/
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public static Ulid fast() {
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final long time = System.currentTimeMillis();
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ThreadLocalRandom random = ThreadLocalRandom.current();
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return new Ulid((time << 16) | (random.nextLong() & 0xffffL), random.nextLong());
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}
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/**
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* Returns the minimum ULID for a given time.
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* <p>
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* The 48 bits of the time component are filled with the given time and the 80
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* bits of the random component are all set to ZERO.
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* <p>
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* For example, the minimum ULID for 2022-02-22 22:22:22.222 is
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* `{@code new Ulid(0x017f2387460e0000L, 0x0000000000000000L)}`, where
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* `{@code 0x017f2387460e}` is the timestamp in hexadecimal.
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* <p>
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* It can be useful to find all records before or after a specific timestamp in
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* a table without a `{@code created_at}` field.
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*
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* @param time the number of milliseconds since 1970-01-01
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* @return a ULID
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* @since 5.2.0
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*/
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public static Ulid min(long time) {
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return new Ulid((time << 16) | 0x0000L, 0x0000000000000000L);
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}
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/**
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* Returns the maximum ULID for a given time.
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* <p>
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* The 48 bits of the time component are filled with the given time and the 80
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* bits or the random component are all set to ONE.
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* <p>
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* For example, the maximum ULID for 2022-02-22 22:22:22.222 is
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* `{@code new Ulid(0x017f2387460effffL, 0xffffffffffffffffL)}`, where
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* `{@code 0x017f2387460e}` is the timestamp in hexadecimal.
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* <p>
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* It can be useful to find all records before or after a specific timestamp in
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* a table without a `{@code created_at}` field.
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*
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* @param time the number of milliseconds since 1970-01-01
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* @return a ULID
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* @since 5.2.0
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*/
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public static Ulid max(long time) {
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return new Ulid((time << 16) | 0xffffL, 0xffffffffffffffffL);
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}
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/**
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* Converts a UUID into a ULID.
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*
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* @param uuid a UUID
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* @return a ULID
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*/
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public static Ulid from(UUID uuid) {
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return new Ulid(uuid.getMostSignificantBits(), uuid.getLeastSignificantBits());
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}
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/**
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* Converts a byte array into a ULID.
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*
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* @param bytes an array of 16 bytes
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* @return a ULID
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* @throws IllegalArgumentException if bytes are null or its length is not 16
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*/
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public static Ulid from(byte[] bytes) {
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if (bytes == null || bytes.length != ULID_BYTES) {
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throw new IllegalArgumentException("Invalid ULID bytes"); // null or wrong length!
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}
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long msb = 0;
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long lsb = 0;
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msb |= (bytes[0x0] & 0xffL) << 56;
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msb |= (bytes[0x1] & 0xffL) << 48;
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msb |= (bytes[0x2] & 0xffL) << 40;
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msb |= (bytes[0x3] & 0xffL) << 32;
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msb |= (bytes[0x4] & 0xffL) << 24;
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msb |= (bytes[0x5] & 0xffL) << 16;
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msb |= (bytes[0x6] & 0xffL) << 8;
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msb |= (bytes[0x7] & 0xffL);
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lsb |= (bytes[0x8] & 0xffL) << 56;
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lsb |= (bytes[0x9] & 0xffL) << 48;
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lsb |= (bytes[0xa] & 0xffL) << 40;
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lsb |= (bytes[0xb] & 0xffL) << 32;
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lsb |= (bytes[0xc] & 0xffL) << 24;
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lsb |= (bytes[0xd] & 0xffL) << 16;
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lsb |= (bytes[0xe] & 0xffL) << 8;
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lsb |= (bytes[0xf] & 0xffL);
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return new Ulid(msb, lsb);
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}
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/**
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* Converts a canonical string into a ULID.
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* <p>
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* The input string must be 26 characters long and must contain only characters
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* from Crockford's base 32 alphabet.
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* <p>
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* The first character of the input string must be between 0 and 7.
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*
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* @param string a canonical string
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* @return a ULID
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* @throws IllegalArgumentException if the input string is invalid
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* @see <a href="https://www.crockford.com/base32.html">Crockford's Base 32</a>
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*/
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public static Ulid from(String string) {
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final char[] chars = toCharArray(string);
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long time = 0;
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long random0 = 0;
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long random1 = 0;
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time |= (long) ALPHABET_VALUES[chars[0x00]] << 45;
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time |= (long) ALPHABET_VALUES[chars[0x01]] << 40;
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time |= (long) ALPHABET_VALUES[chars[0x02]] << 35;
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time |= (long) ALPHABET_VALUES[chars[0x03]] << 30;
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time |= (long) ALPHABET_VALUES[chars[0x04]] << 25;
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time |= (long) ALPHABET_VALUES[chars[0x05]] << 20;
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time |= (long) ALPHABET_VALUES[chars[0x06]] << 15;
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time |= (long) ALPHABET_VALUES[chars[0x07]] << 10;
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time |= (long) ALPHABET_VALUES[chars[0x08]] << 5;
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time |= (long) ALPHABET_VALUES[chars[0x09]];
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random0 |= (long) ALPHABET_VALUES[chars[0x0a]] << 35;
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random0 |= (long) ALPHABET_VALUES[chars[0x0b]] << 30;
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random0 |= (long) ALPHABET_VALUES[chars[0x0c]] << 25;
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random0 |= (long) ALPHABET_VALUES[chars[0x0d]] << 20;
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random0 |= (long) ALPHABET_VALUES[chars[0x0e]] << 15;
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random0 |= (long) ALPHABET_VALUES[chars[0x0f]] << 10;
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random0 |= (long) ALPHABET_VALUES[chars[0x10]] << 5;
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random0 |= (long) ALPHABET_VALUES[chars[0x11]];
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random1 |= (long) ALPHABET_VALUES[chars[0x12]] << 35;
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random1 |= (long) ALPHABET_VALUES[chars[0x13]] << 30;
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random1 |= (long) ALPHABET_VALUES[chars[0x14]] << 25;
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random1 |= (long) ALPHABET_VALUES[chars[0x15]] << 20;
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random1 |= (long) ALPHABET_VALUES[chars[0x16]] << 15;
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random1 |= (long) ALPHABET_VALUES[chars[0x17]] << 10;
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random1 |= (long) ALPHABET_VALUES[chars[0x18]] << 5;
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random1 |= (long) ALPHABET_VALUES[chars[0x19]];
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final long msb = (time << 16) | (random0 >>> 24);
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final long lsb = (random0 << 40) | (random1 & 0xffffffffffL);
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return new Ulid(msb, lsb);
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}
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/**
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* Convert the ULID into a UUID.
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* <p>
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* A ULID has 128-bit compatibility with a {@link UUID}.
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* <p>
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* If you need a RFC-4122 UUIDv4 do this: {@code Ulid.toRfc4122().toUuid()}.
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*
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* @return a UUID.
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*/
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public UUID toUuid() {
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return new UUID(this.msb, this.lsb);
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}
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/**
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* Convert the ULID into a byte array.
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*
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* @return a byte array.
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*/
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public byte[] toBytes() {
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final byte[] bytes = new byte[ULID_BYTES];
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bytes[0x0] = (byte) (msb >>> 56);
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bytes[0x1] = (byte) (msb >>> 48);
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bytes[0x2] = (byte) (msb >>> 40);
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bytes[0x3] = (byte) (msb >>> 32);
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bytes[0x4] = (byte) (msb >>> 24);
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bytes[0x5] = (byte) (msb >>> 16);
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bytes[0x6] = (byte) (msb >>> 8);
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bytes[0x7] = (byte) (msb);
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bytes[0x8] = (byte) (lsb >>> 56);
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bytes[0x9] = (byte) (lsb >>> 48);
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bytes[0xa] = (byte) (lsb >>> 40);
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bytes[0xb] = (byte) (lsb >>> 32);
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bytes[0xc] = (byte) (lsb >>> 24);
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bytes[0xd] = (byte) (lsb >>> 16);
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bytes[0xe] = (byte) (lsb >>> 8);
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bytes[0xf] = (byte) (lsb);
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return bytes;
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}
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/**
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* Converts the ULID into a canonical string in upper case.
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* <p>
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* The output string is 26 characters long and contains only characters from
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* Crockford's Base 32 alphabet.
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* <p>
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* For lower case string, use the shorthand {@code Ulid#toLowerCase()}, instead
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* of {@code Ulid#toString()#toLowerCase()}.
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*
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* @return a ULID string
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* @see <a href="https://www.crockford.com/base32.html">Crockford's Base 32</a>
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*/
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@Override
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public String toString() {
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return toString(ALPHABET_UPPERCASE);
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}
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/**
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* Converts the ULID into a canonical string in lower case.
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* <p>
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* The output string is 26 characters long and contains only characters from
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* Crockford's Base 32 alphabet.
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* <p>
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* It is a shorthand at least twice as fast as
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* {@code Ulid.toString().toLowerCase()}.
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*
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* @return a string
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* @see <a href="https://www.crockford.com/base32.html">Crockford's Base 32</a>
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*/
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public String toLowerCase() {
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return toString(ALPHABET_LOWERCASE);
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}
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/**
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* Converts the ULID into another ULID that is compatible with UUIDv4.
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* <p>
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* The bytes of the returned ULID are compliant with the RFC-4122 version 4.
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* <p>
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* If you need a RFC-4122 UUIDv4 do this: {@code Ulid.toRfc4122().toUuid()}.
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* <p>
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* <b>Note:</b> If you use this method, you can not get the original ULID, since
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* it changes 6 bits of it to generate a UUIDv4.
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*
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* @return a ULID
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* @see <a href="https://www.rfc-editor.org/rfc/rfc4122">RFC-4122</a>
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*/
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public Ulid toRfc4122() {
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// set the 4 most significant bits of the 7th byte to 0, 1, 0 and 0
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final long msb4 = (this.msb & 0xffffffffffff0fffL) | 0x0000000000004000L; // RFC-4122 version 4
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// set the 2 most significant bits of the 9th byte to 1 and 0
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final long lsb4 = (this.lsb & 0x3fffffffffffffffL) | 0x8000000000000000L; // RFC-4122 variant 2
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return new Ulid(msb4, lsb4);
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}
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/**
|
|
* Returns the instant of creation.
|
|
* <p>
|
|
* The instant of creation is extracted from the time component.
|
|
*
|
|
* @return the {@link Instant} of creation
|
|
*/
|
|
public Instant getInstant() {
|
|
return Instant.ofEpochMilli(this.getTime());
|
|
}
|
|
|
|
/**
|
|
* Returns the instant of creation.
|
|
* <p>
|
|
* The instant of creation is extracted from the time component.
|
|
*
|
|
* @param string a canonical string
|
|
* @return the {@link Instant} of creation
|
|
* @throws IllegalArgumentException if the input string is invalid
|
|
*/
|
|
public static Instant getInstant(String string) {
|
|
return Instant.ofEpochMilli(getTime(string));
|
|
}
|
|
|
|
/**
|
|
* Returns the time component as a number.
|
|
* <p>
|
|
* The time component is a number between 0 and 2^48-1. It is equivalent to the
|
|
* count of milliseconds since 1970-01-01 (Unix epoch).
|
|
*
|
|
* @return a number of milliseconds
|
|
*/
|
|
public long getTime() {
|
|
return this.msb >>> 16;
|
|
}
|
|
|
|
/**
|
|
* Returns the time component as a number.
|
|
* <p>
|
|
* The time component is a number between 0 and 2^48-1. It is equivalent to the
|
|
* count of milliseconds since 1970-01-01 (Unix epoch).
|
|
*
|
|
* @param string a canonical string
|
|
* @return a number of milliseconds
|
|
* @throws IllegalArgumentException if the input string is invalid
|
|
*/
|
|
public static long getTime(String string) {
|
|
|
|
final char[] chars = toCharArray(string);
|
|
|
|
long time = 0;
|
|
|
|
time |= (long) ALPHABET_VALUES[chars[0x00]] << 45;
|
|
time |= (long) ALPHABET_VALUES[chars[0x01]] << 40;
|
|
time |= (long) ALPHABET_VALUES[chars[0x02]] << 35;
|
|
time |= (long) ALPHABET_VALUES[chars[0x03]] << 30;
|
|
time |= (long) ALPHABET_VALUES[chars[0x04]] << 25;
|
|
time |= (long) ALPHABET_VALUES[chars[0x05]] << 20;
|
|
time |= (long) ALPHABET_VALUES[chars[0x06]] << 15;
|
|
time |= (long) ALPHABET_VALUES[chars[0x07]] << 10;
|
|
time |= (long) ALPHABET_VALUES[chars[0x08]] << 5;
|
|
time |= (long) ALPHABET_VALUES[chars[0x09]];
|
|
|
|
return time;
|
|
}
|
|
|
|
/**
|
|
* Returns the random component as a byte array.
|
|
* <p>
|
|
* The random component is an array of 10 bytes (80 bits).
|
|
*
|
|
* @return a byte array
|
|
*/
|
|
public byte[] getRandom() {
|
|
|
|
final byte[] bytes = new byte[RANDOM_BYTES];
|
|
|
|
bytes[0x0] = (byte) (msb >>> 8);
|
|
bytes[0x1] = (byte) (msb);
|
|
|
|
bytes[0x2] = (byte) (lsb >>> 56);
|
|
bytes[0x3] = (byte) (lsb >>> 48);
|
|
bytes[0x4] = (byte) (lsb >>> 40);
|
|
bytes[0x5] = (byte) (lsb >>> 32);
|
|
bytes[0x6] = (byte) (lsb >>> 24);
|
|
bytes[0x7] = (byte) (lsb >>> 16);
|
|
bytes[0x8] = (byte) (lsb >>> 8);
|
|
bytes[0x9] = (byte) (lsb);
|
|
|
|
return bytes;
|
|
}
|
|
|
|
/**
|
|
* Returns the random component as a byte array.
|
|
* <p>
|
|
* The random component is an array of 10 bytes (80 bits).
|
|
*
|
|
* @param string a canonical string
|
|
* @return a byte array
|
|
* @throws IllegalArgumentException if the input string is invalid
|
|
*/
|
|
public static byte[] getRandom(String string) {
|
|
|
|
final char[] chars = toCharArray(string);
|
|
|
|
long random0 = 0;
|
|
long random1 = 0;
|
|
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0a]] << 35;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0b]] << 30;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0c]] << 25;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0d]] << 20;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0e]] << 15;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x0f]] << 10;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x10]] << 5;
|
|
random0 |= (long) ALPHABET_VALUES[chars[0x11]];
|
|
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x12]] << 35;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x13]] << 30;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x14]] << 25;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x15]] << 20;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x16]] << 15;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x17]] << 10;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x18]] << 5;
|
|
random1 |= (long) ALPHABET_VALUES[chars[0x19]];
|
|
|
|
final byte[] bytes = new byte[RANDOM_BYTES];
|
|
|
|
bytes[0x0] = (byte) (random0 >>> 32);
|
|
bytes[0x1] = (byte) (random0 >>> 24);
|
|
bytes[0x2] = (byte) (random0 >>> 16);
|
|
bytes[0x3] = (byte) (random0 >>> 8);
|
|
bytes[0x4] = (byte) (random0);
|
|
|
|
bytes[0x5] = (byte) (random1 >>> 32);
|
|
bytes[0x6] = (byte) (random1 >>> 24);
|
|
bytes[0x7] = (byte) (random1 >>> 16);
|
|
bytes[0x8] = (byte) (random1 >>> 8);
|
|
bytes[0x9] = (byte) (random1);
|
|
|
|
return bytes;
|
|
}
|
|
|
|
/**
|
|
* Returns the most significant bits as a number.
|
|
*
|
|
* @return a number.
|
|
*/
|
|
public long getMostSignificantBits() {
|
|
return this.msb;
|
|
}
|
|
|
|
/**
|
|
* Returns the least significant bits as a number.
|
|
*
|
|
* @return a number.
|
|
*/
|
|
public long getLeastSignificantBits() {
|
|
return this.lsb;
|
|
}
|
|
|
|
/**
|
|
* Returns a new ULID by incrementing the random component of the current ULID.
|
|
* <p>
|
|
* Since the random component contains 80 bits:
|
|
* <ul>
|
|
* <li>(1) This method can generate up to 1208925819614629174706176 (2^80) ULIDs
|
|
* per millisecond;
|
|
* <li>(2) This method can generate monotonic increasing ULIDs
|
|
* 99.999999999999992% ((2^80 - 10^9) / (2^80)) of the time within a single
|
|
* millisecond interval, considering an unrealistic rate of 1,000,000,000 ULIDs
|
|
* per millisecond.
|
|
* </ul>
|
|
* <p>
|
|
* Due to (1) and (2), it does not throw the error message recommended by the
|
|
* specification. When an overflow occurs in the random 80 bits, the time
|
|
* component is simply incremented to <b>maintain monotonicity</b>.
|
|
*
|
|
* @return a ULID
|
|
*/
|
|
public Ulid increment() {
|
|
|
|
long newMsb = this.msb;
|
|
long newLsb = this.lsb + 1; // increment the LEAST significant bits
|
|
|
|
if (newLsb == INCREMENT_OVERFLOW) {
|
|
newMsb += 1; // increment the MOST significant bits
|
|
}
|
|
|
|
return new Ulid(newMsb, newLsb);
|
|
}
|
|
|
|
/**
|
|
* Checks if the input string is valid.
|
|
* <p>
|
|
* The input string must be 26 characters long and must contain only characters
|
|
* from Crockford's base 32 alphabet.
|
|
* <p>
|
|
* The first character of the input string must be between 0 and 7.
|
|
*
|
|
* @param string a canonical string
|
|
* @return true if the input string is valid
|
|
* @see <a href="https://www.crockford.com/base32.html">Crockford's Base 32</a>
|
|
*/
|
|
public static boolean isValid(String string) {
|
|
return string != null && isValidCharArray(string.toCharArray());
|
|
}
|
|
|
|
/**
|
|
* Returns a hash code value for the ULID.
|
|
*/
|
|
@Override
|
|
public int hashCode() {
|
|
final long bits = msb ^ lsb;
|
|
return (int) (bits ^ (bits >>> 32));
|
|
}
|
|
|
|
/**
|
|
* Checks if some other ULID is equal to this one.
|
|
*/
|
|
@Override
|
|
public boolean equals(Object other) {
|
|
if (other == null)
|
|
return false;
|
|
if (other.getClass() != Ulid.class)
|
|
return false;
|
|
Ulid that = (Ulid) other;
|
|
if (lsb != that.lsb)
|
|
return false;
|
|
else if (msb != that.msb)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Compares two ULIDs as unsigned 128-bit integers.
|
|
* <p>
|
|
* The first of two ULIDs is greater than the second if the most significant
|
|
* byte in which they differ is greater for the first ULID.
|
|
*
|
|
* @param that a ULID to be compared with
|
|
* @return -1, 0 or 1 as {@code this} is less than, equal to, or greater than
|
|
* {@code that}
|
|
*/
|
|
@Override
|
|
public int compareTo(Ulid that) {
|
|
|
|
// used to compare as UNSIGNED longs
|
|
final long min = 0x8000000000000000L;
|
|
|
|
final long a = this.msb + min;
|
|
final long b = that.msb + min;
|
|
|
|
if (a > b)
|
|
return 1;
|
|
else if (a < b)
|
|
return -1;
|
|
|
|
final long c = this.lsb + min;
|
|
final long d = that.lsb + min;
|
|
|
|
if (c > d)
|
|
return 1;
|
|
else if (c < d)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
String toString(char[] alphabet) {
|
|
|
|
final char[] chars = new char[ULID_CHARS];
|
|
|
|
long time = this.msb >>> 16;
|
|
long random0 = ((this.msb & 0xffffL) << 24) | (this.lsb >>> 40);
|
|
long random1 = (this.lsb & 0xffffffffffL);
|
|
|
|
chars[0x00] = alphabet[(int) (time >>> 45 & 0b11111)];
|
|
chars[0x01] = alphabet[(int) (time >>> 40 & 0b11111)];
|
|
chars[0x02] = alphabet[(int) (time >>> 35 & 0b11111)];
|
|
chars[0x03] = alphabet[(int) (time >>> 30 & 0b11111)];
|
|
chars[0x04] = alphabet[(int) (time >>> 25 & 0b11111)];
|
|
chars[0x05] = alphabet[(int) (time >>> 20 & 0b11111)];
|
|
chars[0x06] = alphabet[(int) (time >>> 15 & 0b11111)];
|
|
chars[0x07] = alphabet[(int) (time >>> 10 & 0b11111)];
|
|
chars[0x08] = alphabet[(int) (time >>> 5 & 0b11111)];
|
|
chars[0x09] = alphabet[(int) (time & 0b11111)];
|
|
|
|
chars[0x0a] = alphabet[(int) (random0 >>> 35 & 0b11111)];
|
|
chars[0x0b] = alphabet[(int) (random0 >>> 30 & 0b11111)];
|
|
chars[0x0c] = alphabet[(int) (random0 >>> 25 & 0b11111)];
|
|
chars[0x0d] = alphabet[(int) (random0 >>> 20 & 0b11111)];
|
|
chars[0x0e] = alphabet[(int) (random0 >>> 15 & 0b11111)];
|
|
chars[0x0f] = alphabet[(int) (random0 >>> 10 & 0b11111)];
|
|
chars[0x10] = alphabet[(int) (random0 >>> 5 & 0b11111)];
|
|
chars[0x11] = alphabet[(int) (random0 & 0b11111)];
|
|
|
|
chars[0x12] = alphabet[(int) (random1 >>> 35 & 0b11111)];
|
|
chars[0x13] = alphabet[(int) (random1 >>> 30 & 0b11111)];
|
|
chars[0x14] = alphabet[(int) (random1 >>> 25 & 0b11111)];
|
|
chars[0x15] = alphabet[(int) (random1 >>> 20 & 0b11111)];
|
|
chars[0x16] = alphabet[(int) (random1 >>> 15 & 0b11111)];
|
|
chars[0x17] = alphabet[(int) (random1 >>> 10 & 0b11111)];
|
|
chars[0x18] = alphabet[(int) (random1 >>> 5 & 0b11111)];
|
|
chars[0x19] = alphabet[(int) (random1 & 0b11111)];
|
|
|
|
return new String(chars);
|
|
}
|
|
|
|
static char[] toCharArray(String string) {
|
|
char[] chars = string == null ? null : string.toCharArray();
|
|
if (!isValidCharArray(chars)) {
|
|
throw new IllegalArgumentException(String.format("Invalid ULID: \"%s\"", string));
|
|
}
|
|
return chars;
|
|
}
|
|
|
|
/*
|
|
* Checks if the string is a valid ULID.
|
|
*
|
|
* A valid ULID string is a sequence of 26 characters from Crockford's Base 32
|
|
* alphabet.
|
|
*
|
|
* The first character of the input string must be between 0 and 7.
|
|
*/
|
|
static boolean isValidCharArray(final char[] chars) {
|
|
|
|
if (chars == null || chars.length != ULID_CHARS) {
|
|
return false; // null or wrong size!
|
|
}
|
|
|
|
// The time component has 48 bits.
|
|
// The base32 encoded time component has 50 bits.
|
|
// The time component cannot be greater than than 2^48-1.
|
|
// So the 2 first bits of the base32 decoded time component must be ZERO.
|
|
// As a consequence, the 1st char of the input string must be between 0 and 7.
|
|
if ((ALPHABET_VALUES[chars[0]] & 0b11000) != 0) {
|
|
// ULID specification:
|
|
// "Any attempt to decode or encode a ULID larger than this (time > 2^48-1)
|
|
// should be rejected by all implementations, to prevent overflow bugs."
|
|
return false; // time overflow!
|
|
}
|
|
|
|
for (int i = 0; i < chars.length; i++) {
|
|
if (ALPHABET_VALUES[chars[i]] == -1) {
|
|
return false; // invalid character!
|
|
}
|
|
}
|
|
|
|
return true; // It seems to be OK.
|
|
}
|
|
}
|