UTCTime package:rebase

This is the simplest representation of UTC. It consists of the day number, and a time offset from midnight. Note that if a day has a leap second added to it, it will have 86401 seconds.

addUTCTime a b = a + b

diffUTCTime a b = a - b

Convert a time of day in some timezone to a time of day in UTC, together with a day adjustment.

Convert SystemTime to UTCTime, matching zero SystemTime to midnight of systemEpochDay UTC.