datetime arithmetic over business calendar

[Massimiliano Campagnoli]

Hy All,
is there a library in C++ supporting datetime arithmetic over a given
business calendar.
For instance, a typical 8 hours shift in a company is from 8am to
12am and from 1:30pm to 5:30pm with a break interval between 12 and
1:30pm

So 11am + 2 hours should gives 2:30pm and not 12 as expected because
the time interval is not a continuum but is a sequence of working
intervals and not working intervals.

Any help is really appreciated.