php: generate UUID

php-generaterUUID

 function gen_uuid() {
	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 )
	  );
 }