ios - Comparing Hours in Swift -

while querying data database receive hours process started , ended in 2 separate string fields example start = "1100" , end = "+0200" indicate it's hours of operation 11am-2am. proper way represent in swift can determine amount of time left current time end time of process.

edit: found interesting way using date formatter if remove possible prefix of + , use below code seems work correctly; however, date not set work around?

let dateformatter = nsdateformatter() dateformatter.dateformat = "hhmm" let date = dateformatter.datefromstring("1340") 

you can create nsdate components using nscalendar.currentcalendar().datewithera (there other similar functions, nscalendar details). need add logic determine if 2am today or tomorrow etc.

then can compare 2 nsdate dates. determine time left end use nsdate method timeintervalsincedate. can use nsdatecomponentsformatter remaining time nicely formatted.