58 lines
1.7 KiB
PHP
58 lines
1.7 KiB
PHP
<?php
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/**
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* This file is part of the ramsey/uuid library
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*
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* @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
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* @license http://opensource.org/licenses/MIT MIT
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* @link https://benramsey.com/projects/ramsey-uuid/ Documentation
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* @link https://packagist.org/packages/ramsey/uuid Packagist
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* @link https://github.com/ramsey/uuid GitHub
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*/
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namespace Ramsey\Uuid\Provider\Node;
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use Exception;
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use Ramsey\Uuid\Provider\NodeProviderInterface;
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/**
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* RandomNodeProvider provides functionality to generate a random node ID, in
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* the event that the node ID could not be obtained from the host system
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*
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* @link http://tools.ietf.org/html/rfc4122#section-4.5
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*/
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class RandomNodeProvider implements NodeProviderInterface
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{
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/**
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* Returns the system node ID
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*
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* @return string System node ID as a hexadecimal string
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* @throws Exception if it was not possible to gather sufficient entropy
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*/
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public function getNode()
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{
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$nodeBytes = random_bytes(6);
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// Split the node bytes for math on 32-bit systems.
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$nodeMsb = substr($nodeBytes, 0, 3);
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$nodeLsb = substr($nodeBytes, 3);
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// Set the multicast bit; see RFC 4122, section 4.5.
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$nodeMsb = hex2bin(
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str_pad(
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dechex(hexdec(bin2hex($nodeMsb)) | 0x010000),
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6,
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'0',
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STR_PAD_LEFT
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)
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);
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// Recombine the node bytes.
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$node = $nodeMsb . $nodeLsb;
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return str_pad(bin2hex($node), 12, '0', STR_PAD_LEFT);
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}
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}
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