public function toDelta()
{
$diffs = $this->getChanges();
$text = array();
foreach ($diffs as $change) {
$op = $change[0];
$data = $change[1];
if ($op == self::INSERT) {
$text[] = '+' . Utils::escapeString($data);
} elseif ($op == self::DELETE) {
$text[] = '-' . mb_strlen($data);
} else {
$text[] = '=' . mb_strlen($data);
}
}
return implode("\t", $text);
}