{-# OPTIONS -Wall -Werror #-} -- #hide module Data.Time.Clock.UTC ( -- * UTC -- | UTC is time as measured by a clock, corrected to keep pace with the earth by adding or removing -- occasional seconds, known as \"leap seconds\". -- These corrections are not predictable and are announced with six month's notice. -- No table of these corrections is provided, as any program compiled with it would become -- out of date in six months. -- -- If you don't care about leap seconds, use UTCTime and NominalDiffTime for your clock calculations, -- and you'll be fine. UTCTime(..),NominalDiffTime ) where import Data.Time.Calendar.Days import Data.Time.Clock.Scale import Data.Fixed -- | 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. data UTCTime = UTCTime { -- | the day utctDay :: Day, -- | the time from midnight, 0 <= t < 86401s (because of leap-seconds) utctDayTime :: DiffTime } instance Eq UTCTime where (UTCTime da ta) == (UTCTime db tb) = (da == db) && (ta == tb) instance Ord UTCTime where compare (UTCTime da ta) (UTCTime db tb) = case (compare da db) of EQ -> compare ta tb cmp -> cmp -- | This is a length of time, as measured by UTC. -- Conversion functions will treat it as seconds. -- It has an accuracy of 10^-12 s. -- It ignores leap-seconds, so it's not necessarily a fixed amount of clock time. -- For instance, 23:00 UTC + 2 hours of NominalDiffTime = 01:00 UTC (+ 1 day), -- regardless of whether a leap-second intervened. newtype NominalDiffTime = MkNominalDiffTime Pico deriving (Eq,Ord) instance Enum NominalDiffTime where succ (MkNominalDiffTime a) = MkNominalDiffTime (succ a) pred (MkNominalDiffTime a) = MkNominalDiffTime (pred a) toEnum = MkNominalDiffTime . toEnum fromEnum (MkNominalDiffTime a) = fromEnum a enumFrom (MkNominalDiffTime a) = fmap MkNominalDiffTime (enumFrom a) enumFromThen (MkNominalDiffTime a) (MkNominalDiffTime b) = fmap MkNominalDiffTime (enumFromThen a b) enumFromTo (MkNominalDiffTime a) (MkNominalDiffTime b) = fmap MkNominalDiffTime (enumFromTo a b) enumFromThenTo (MkNominalDiffTime a) (MkNominalDiffTime b) (MkNominalDiffTime c) = fmap MkNominalDiffTime (enumFromThenTo a b c) instance Show NominalDiffTime where show (MkNominalDiffTime t) = (showFixed True t) ++ "s" -- necessary because H98 doesn't have "cunning newtype" derivation instance Num NominalDiffTime where (MkNominalDiffTime a) + (MkNominalDiffTime b) = MkNominalDiffTime (a + b) (MkNominalDiffTime a) - (MkNominalDiffTime b) = MkNominalDiffTime (a - b) (MkNominalDiffTime a) * (MkNominalDiffTime b) = MkNominalDiffTime (a * b) negate (MkNominalDiffTime a) = MkNominalDiffTime (negate a) abs (MkNominalDiffTime a) = MkNominalDiffTime (abs a) signum (MkNominalDiffTime a) = MkNominalDiffTime (signum a) fromInteger i = MkNominalDiffTime (fromInteger i) -- necessary because H98 doesn't have "cunning newtype" derivation instance Real NominalDiffTime where toRational (MkNominalDiffTime a) = toRational a -- necessary because H98 doesn't have "cunning newtype" derivation instance Fractional NominalDiffTime where (MkNominalDiffTime a) / (MkNominalDiffTime b) = MkNominalDiffTime (a / b) recip (MkNominalDiffTime a) = MkNominalDiffTime (recip a) fromRational r = MkNominalDiffTime (fromRational r) -- necessary because H98 doesn't have "cunning newtype" derivation instance RealFrac NominalDiffTime where properFraction (MkNominalDiffTime a) = (i,MkNominalDiffTime f) where (i,f) = properFraction a truncate (MkNominalDiffTime a) = truncate a round (MkNominalDiffTime a) = round a ceiling (MkNominalDiffTime a) = ceiling a floor (MkNominalDiffTime a) = floor a