How can I limit the length of the previous/next posts in my WordPress Theme?

I am using the following code to show next/previous posts in my wordpress theme.

<?php
previous_post_link('<span class="left">&larr; %link</span>');
next_post_link('<span class="right">%link &rarr;</span>'); ?> 

It’s working but I want to limit the post title which is displayed in the link to a specific length because too big links don’t work because of the space I have.
And I want to have the arrow within the link so that it shows link and arrow with the same style. Is that possible aswell?

Thank you!