Uuid4.php

<?php
/*
 * Copyright 2017-2018 Derrek Bertrand <[email protected]>
 * Copyright 2018 CollabCorp Group
 *
 * License: MIT
 */

use Exception;

/**
 * Small UUID v4 Class
 *
 * Requires:
 * - A 64 bit PHP runtime
 * - Probably a little endian system
 * - PHP 7+
 */
class Uuid4
{
    protected $value = null;

    public function __construct($value = null)
    {
        // This implementation only runs on a 64 bit system!
        // Although, it is set up to at least have the possibility of being
        // ported to other architectures.
        if (PHP_INT_SIZE !== 8) {
            throw new Exception('Uuid4 only runs on 64 bit systems!');
        }

        // set the value if provided, otherwise do nothing
        if ($value !== null) {
            $this->setValue($value);
        }
    }

    /**
     * Returns the value as a base 64 string.
     *
     * @return string
     */
    public function getBase64()
    {
        return base64_encode($this->getBytes());
    }

    /**
     * Returns the value as a binary string; generates one if not set.
     *
     * @return string
     */
    public function getBytes()
    {
        return $this->value ?? $this->setValue()->value;
    }

    /**
     * Returns the value as a hexadecimal string.
     *
     * @return string
     */
    public function getHex()
    {
        return bin2hex($this->getBytes());
    }

    /**
     * Returns the value as a UUIDv4-style string.
     *
     * @return string
     */
    public function getUuidV4()
    {
        return implode('-', unpack('H8a/H4b/H4c/H4d/H12e', $this->getBytes()));
    }

    /**
     * Set or generate a new Ksuid.
     *
     * @param mixed $value
     * @return $this
     */
    public function setValue($value = null)
    {
        if ($value === null) {
            // no value is provided, generate one
            $pack = unpack('H8a/H4b/nc/nd/H12e', random_bytes(16));
            $pack['c'] = dechex($pack['c'] & 0x0fff | 0x4000); //UUID version
            $pack['d'] = dechex($pack['d'] & 0x3fff | 0x8000); //reserved bits
            $this->value = hex2bin(implode($pack));
        } elseif ($value instanceof Ksuid) {
            // set from another Ksuid
            $this->value = $value->getBytes();
        } elseif (is_string($value) && strlen($value) === 32 && preg_match('/[^0-9A-Fa-f]/', $value) === 0) {
            // a hexadecimal value is provided
            $this->value = hex2bin($value);
        } else {
            throw new Exception('Uuid4 only accepts hexadecimal strings when setting value.');
        }

        return $this;
    }

    /**
     * Returns the value as a string.
     *
     * @return string
     */
    public function __toString()
    {
        return $this->getBytes();
    }
}