README.md

leapseconds-announced

This libraray provides a static Data.Time.Clock.TAI.LeapSecondTable "containing" the leap seconds announced at library release time. A new version of the library is released every time the International Earth Rotation and Reference Systems Service (IERS) announces a new leap second at http://hpiers.obspm.fr/eoppc/bul/bulc/bulletinc.dat.

This module is intended to provide a quick-and-dirty leap second solution for one-off analyses concerned only with the past and present (i.e. up until the next as of yet unannounced leap second), or for applications which can afford to be recompiled against an updated library as often as every six months.

Usage

Import Data.Time.Clock.AnnouncedLeapSeconds to bring the leap second table lst into scope. Here is a usage example:

import Data.Time
import Data.Time.Clock.TAI
import Data.Time.Clock.AnnouncedLeapSeconds

-- | Convert from UTC to TAI.
utcToTAITime' = utcToTAITime lst
-- | Convert from TAI to UTC.
taiToUTCTime' = taiToUTCTime lst

-- | Add a length of time to a UTC time, respecting leap seconds
--   (as opposed to Data.Time.Clock.addUTCTime).
addUTCTime' :: DiffTime -> UTCTime -> Maybe UTCTime
addUTCTime' dt utc = taiToUTCTime' . addAbsoluteTime dt =<< utcToTAITime' utc