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<?php
/**
* This file is part of the ramsey/uuid library
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*
* @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
* @license http://opensource.org/licenses/MIT MIT
*/
declare(strict_types=1);
namespace Ramsey\Uuid\Rfc4122;
use Ramsey\Uuid\Exception\InvalidBytesException;
use Ramsey\Uuid\Uuid;
use function decbin;
use function str_pad;
use function strlen;
use function strpos;
use function substr;
use function unpack;
use const STR_PAD_LEFT;
/**
* Provides common functionality for handling the variant, as defined by RFC 4122
*
* @psalm-immutable
*/
trait VariantTrait
{
/**
* Returns the bytes that comprise the fields
*/
abstract public function getBytes(): string;
/**
* Returns the variant identifier, according to RFC 4122, for the given bytes
*
* The following values may be returned:
*
* - `0` -- Reserved, NCS backward compatibility.
* - `2` -- The variant specified in RFC 4122.
* - `6` -- Reserved, Microsoft Corporation backward compatibility.
* - `7` -- Reserved for future definition.
*
* @link https://tools.ietf.org/html/rfc4122#section-4.1.1 RFC 4122, § 4.1.1: Variant
*
* @return int The variant identifier, according to RFC 4122
*/
public function getVariant(): int
{
if (strlen($this->getBytes()) !== 16) {
throw new InvalidBytesException('Invalid number of bytes');
}
/** @var array $parts */
$parts = unpack('n*', $this->getBytes());
// $parts[5] is a 16-bit, unsigned integer containing the variant bits
// of the UUID. We convert this integer into a string containing a
// binary representation, padded to 16 characters. We analyze the first
// three characters (three most-significant bits) to determine the
// variant.
$binary = str_pad(
decbin((int) $parts[5]),
16,
'0',
STR_PAD_LEFT
);
$msb = substr($binary, 0, 3);
if ($msb === '111') {
$variant = Uuid::RESERVED_FUTURE;
} elseif ($msb === '110') {
$variant = Uuid::RESERVED_MICROSOFT;
} elseif (strpos($msb, '10') === 0) {
$variant = Uuid::RFC_4122;
} else {
$variant = Uuid::RESERVED_NCS;
}
return $variant;
}
}
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