Objective-c – cocoa library for advanced date + time handling


I need to do some date + time stuff that is not covered well by NSDate on the iPhone. I wonder if there is a library that has more sophisticated functionality regarding dates and time on a international level.

What I want to do is advanced date + time mathemathics. I need to:

  • convert between different calendar types (Gregorian <> Jewish <> Muslimish <> others)
  • convert times between different time zones (i.e. I have a swedish time and want to know what time is it in chicago)
  • add microseconds, seconds, minutes, hours, days, weeks, months, years to a date and find out what exact date+time it is then
  • find out how many microseconds, seconds, minutes, hours, days, weeks, months and years are between two given dates
  • draw calendars, so I need data about how many days a specific month has in a specific year

use case, for example: I fly from paris to chicago, and at 10:00 'clock in paris I only know the flight will take 10 hours. So I need to convert time zones and all this stuff to calculate what time I'll arrive in chicago. And then all this ugly summer and winter time stuff where they add or reduce one hour at some point in the year, and I think every country does that to their own liking, some may even fake the time way more than that adding a whole day to a year just to have more time. Don't know. Maybe there's a lib that protects me from all this complexity.

Basically what I want to do is a kind of world calendar but with some special features.

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