Calculating rollover sounds complicated, but it is fairly straightforward, you need the following 3 pieces of information:
1. The exchange rate of the pair you are trading
2. The interest rate of both currencies you have traded
3. How much you have actually traded

Yes you will need those three elements, but you did not specify how it is calculated... First you will need to subtract the interest rate of the base currency from the interest of the quote currency. The answer you get will then need to be divided by 365 times the base exchange rate.