{-# OPTIONS -fno-warn-orphans #-} module Data.Time.LocalTime.Internal.LocalTime ( -- * Local Time LocalTime(..) , addLocalTime , diffLocalTime -- converting UTC and UT1 times to LocalTime , utcToLocalTime , localTimeToUTC , ut1ToLocalTime , localTimeToUT1 ) where import Control.DeepSeq import Data.Data import Data.Time.Calendar.Days import Data.Time.Calendar.Gregorian import Data.Time.Clock.Internal.NominalDiffTime import Data.Time.Clock.Internal.UTCDiff import Data.Time.Clock.Internal.UTCTime import Data.Time.Clock.Internal.UniversalTime import Data.Time.LocalTime.Internal.TimeOfDay import Data.Time.LocalTime.Internal.TimeZone -- | A simple day and time aggregate, where the day is of the specified parameter, -- and the time is a TimeOfDay. -- Conversion of this (as local civil time) to UTC depends on the time zone. -- Conversion of this (as local mean time) to UT1 depends on the longitude. data LocalTime = LocalTime { localDay :: Day , localTimeOfDay :: TimeOfDay } deriving (Eq, Ord, Data, Typeable) instance NFData LocalTime where rnf (LocalTime d t) = rnf d `seq` rnf t `seq` () instance Show LocalTime where show (LocalTime d t) = (showGregorian d) ++ " " ++ (show t) -- | addLocalTime a b = a + b addLocalTime :: NominalDiffTime -> LocalTime -> LocalTime addLocalTime x = utcToLocalTime utc . addUTCTime x . localTimeToUTC utc -- | diffLocalTime a b = a - b diffLocalTime :: LocalTime -> LocalTime -> NominalDiffTime diffLocalTime a b = diffUTCTime (localTimeToUTC utc a) (localTimeToUTC utc b) -- | Get the local time of a UTC time in a time zone. utcToLocalTime :: TimeZone -> UTCTime -> LocalTime utcToLocalTime tz (UTCTime day dt) = LocalTime (addDays i day) tod where (i, tod) = utcToLocalTimeOfDay tz (timeToTimeOfDay dt) -- | Get the UTC time of a local time in a time zone. localTimeToUTC :: TimeZone -> LocalTime -> UTCTime localTimeToUTC tz (LocalTime day tod) = UTCTime (addDays i day) (timeOfDayToTime todUTC) where (i, todUTC) = localToUTCTimeOfDay tz tod -- | Get the local time of a UT1 time on a particular meridian (in degrees, positive is East). ut1ToLocalTime :: Rational -> UniversalTime -> LocalTime ut1ToLocalTime long (ModJulianDate date) = LocalTime (ModifiedJulianDay localMJD) (dayFractionToTimeOfDay localToDOffset) where localTime = date + long / 360 :: Rational localMJD = floor localTime localToDOffset = localTime - (fromIntegral localMJD) -- | Get the UT1 time of a local time on a particular meridian (in degrees, positive is East). localTimeToUT1 :: Rational -> LocalTime -> UniversalTime localTimeToUT1 long (LocalTime (ModifiedJulianDay localMJD) tod) = ModJulianDate ((fromIntegral localMJD) + (timeOfDayToDayFraction tod) - (long / 360)) -- orphan instance instance Show UniversalTime where show t = show (ut1ToLocalTime 0 t)