Sessions in database - How to retrieve/deserialize user_data items

[eluser]mradlmaier[/eluser]
Hello all,

I have my sessions stored in the database.

So the user_data itimes are stored in one long String, which outputted with var_dump() looks like this:

string(86) "a:3:{s:11:"logged_user";s:5:"michi";s:7:"user_id";s:1:"9";s:8:"username";s:5:"michi";}"

Does anybody know an easy way to read the value of user_id and username?

Somewhere in CI there must already exist a function whih does the deserializing of this string.
Just dont know which and how to call that function?

Thanks,
Michael