Eloquent\Phony\Event\EventSequence::normalizeIndex PHP Method

    private function normalizeIndex($size, $index, &$normalized = null)
    {
        $normalized = null;
        if ($index < 0) {
            $potential = $size + $index;
            if ($potential < 0) {
                return false;
            }
        } else {
            $potential = $index;
        }
        if ($potential >= $size) {
            return false;
        }
        $normalized = $potential;
        return true;
    }