Help need Formula to calculate vacation days left based on anniversary date.

My employer is changing from anniversary date to calendar year effective January 2016. I am having problems getting the formula to come out correctly. I want to use there anniversary date in 2014 to 2015 when it starts over. and then as of July 1 2015 to see how much they would have for the year until Dec 2015. also need to add days already use between the 2014 and 2015 time frame

example

my anniversary turns over 3/15/15

hire date 3/3/2014

0-2 years 10days
3-14years 15 days
15 or more 20 days