Address Book Unique Phone Numbers

Is there any library that can take Address Book contacts with phone numbers and convert them to a unique phone number with international country code.

It will be

• Convert local phone numbers to international, after receiving a specific country code.

• Recognize and maintain existing international numbers

This is to achieve something similar to whatsapp by using full phone numbers as usernames and converting users' contacts to full phone numbers to check which of your friends are on whatsapp.

I'm going to try this myself, but I feel like there will be a lot of work in servicing the different phone number configurations out there, so any chapter start will be helpful.