{-# OPTIONS -fno-warn-unused-imports #-} {-# LANGUAGE ForeignFunctionInterface #-} #include "HsConfigure.h" -- #hide module Data.Time.LocalTime.TimeZone ( -- * Time zones TimeZone(..),timeZoneOffsetString,timeZoneOffsetString',minutesToTimeZone,hoursToTimeZone,utc, -- getting the locale time zone getTimeZone,getCurrentTimeZone ) where --import System.Time.Calendar.Format import Data.Time.Calendar.Private import Data.Time.Clock import Data.Time.Clock.POSIX import Foreign.Safe import Foreign.C import Control.DeepSeq import Data.Typeable #if LANGUAGE_Rank2Types import Data.Data #endif -- | A TimeZone is a whole number of minutes offset from UTC, together with a name and a \"just for summer\" flag. data TimeZone = TimeZone { -- | The number of minutes offset from UTC. Positive means local time will be later in the day than UTC. timeZoneMinutes :: Int, -- | Is this time zone just persisting for the summer? timeZoneSummerOnly :: Bool, -- | The name of the zone, typically a three- or four-letter acronym. timeZoneName :: String } deriving (Eq,Ord #if LANGUAGE_DeriveDataTypeable #if LANGUAGE_Rank2Types ,Data, Typeable #endif #endif ) instance NFData TimeZone where rnf (TimeZone m so n) = m `deepseq` so `deepseq` n `deepseq` () -- | Create a nameless non-summer timezone for this number of minutes minutesToTimeZone :: Int -> TimeZone minutesToTimeZone m = TimeZone m False "" -- | Create a nameless non-summer timezone for this number of hours hoursToTimeZone :: Int -> TimeZone hoursToTimeZone i = minutesToTimeZone (60 * i) showT :: NumericPadOption -> Int -> String showT opt t = show4 opt ((div t 60) * 100 + (mod t 60)) -- | Text representing the offset of this timezone, such as \"-0800\" or \"+0400\" (like %z in formatTime), with arbitrary padding timeZoneOffsetString' :: NumericPadOption -> TimeZone -> String timeZoneOffsetString' opt (TimeZone t _ _) | t < 0 = '-':(showT opt (negate t)) timeZoneOffsetString' opt (TimeZone t _ _) = '+':(showT opt t) -- | Text representing the offset of this timezone, such as \"-0800\" or \"+0400\" (like %z in formatTime) timeZoneOffsetString :: TimeZone -> String timeZoneOffsetString = timeZoneOffsetString' (Just '0') instance Show TimeZone where show zone@(TimeZone _ _ "") = timeZoneOffsetString zone show (TimeZone _ _ name) = name -- | The UTC time zone utc :: TimeZone utc = TimeZone 0 False "UTC" {-# CFILES cbits/HsTime.c #-} foreign import ccall unsafe "HsTime.h get_current_timezone_seconds" get_current_timezone_seconds :: CTime -> Ptr CInt -> Ptr CString -> IO CLong posixToCTime :: POSIXTime -> CTime posixToCTime = fromInteger . floor -- | Get the local time-zone for a given time (varying as per summertime adjustments) getTimeZone :: UTCTime -> IO TimeZone getTimeZone time = with 0 (\pdst -> with nullPtr (\pcname -> do secs <- get_current_timezone_seconds (posixToCTime (utcTimeToPOSIXSeconds time)) pdst pcname case secs of 0x80000000 -> fail "localtime_r failed" _ -> do dst <- peek pdst cname <- peek pcname name <- peekCString cname return (TimeZone (div (fromIntegral secs) 60) (dst == 1) name) )) -- | Get the current time-zone getCurrentTimeZone :: IO TimeZone getCurrentTimeZone = getCurrentTime >>= getTimeZone