v4 GUID

v4 GUID.php

public function v4() {
		return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',

			// 32 bits for "time_low"
			mt_rand(0, 0xffff), mt_rand(0, 0xffff),

			// 16 bits for "time_mid"
			mt_rand(0, 0xffff),

			// 16 bits for "time_hi_and_version",
			// four most significant bits holds version number 4
			mt_rand(0, 0x0fff) | 0x4000,

			// 16 bits, 8 bits for "clk_seq_hi_res",
			// 8 bits for "clk_seq_low",
			// two most significant bits holds zero and one for variant DCE1.1
			mt_rand(0, 0x3fff) | 0x8000,

			// 48 bits for "node"
			mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
		);
	}