/**
* @param int $length
* @return string|null
*/
public static function dev($length)
{
if (!is_readable('/dev/urandom')) {
return null;
}
$fp = fopen('/dev/urandom', 'r');
$left = $length;
$result = [];
do {
$buffer = fread($fp, $left);
$lBuffer = Binary::getLength($buffer);
if ($lBuffer === 0) {
fclose($fp);
return null;
}
$result[] = $buffer;
$left -= $lBuffer;
} while ($left > 0);
fclose($fp);
return implode('', $result);
}
