Synchronizing mobile phone contacts with contacts from social networks

I am getting a JSON contact list from a social networking site. It contains the name firstname, lastname, displayname, data1, data2

, firstname, lastname, displayname, data1, data2

etc.

What an efficient way to quickly find my local phone contacts database and "match" them by name. Since there is a name firstname, lastname

and displayname

it can vary.
How do you think you can achieve the best match?

Also how do I make sure that I am not parsing for every JSON item the entire database I want to avoid by following the steps JSON_COUNT x MOBILE COUNT

edit

Still looking for answers.