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|
{- Time for humans.
-
- Copyright 2012-2013 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.HumanTime (
Duration(..),
durationSince,
durationToPOSIXTime,
durationToDays,
daysToDuration,
parseDuration,
fromDuration,
prop_duration_roundtrips
) where
import Utility.PartialPrelude
import Utility.QuickCheck
import qualified Data.Map as M
import Data.Time.Clock
import Data.Time.Clock.POSIX (POSIXTime)
import Data.Char
import Control.Applicative
import Prelude
newtype Duration = Duration { durationSeconds :: Integer }
deriving (Eq, Ord, Read, Show)
durationSince :: UTCTime -> IO Duration
durationSince pasttime = do
now <- getCurrentTime
return $ Duration $ round $ diffUTCTime now pasttime
durationToPOSIXTime :: Duration -> POSIXTime
durationToPOSIXTime = fromIntegral . durationSeconds
durationToDays :: Duration -> Integer
durationToDays d = durationSeconds d `div` dsecs
daysToDuration :: Integer -> Duration
daysToDuration i = Duration $ i * dsecs
{- Parses a human-input time duration, of the form "5h", "1m", "5h1m", etc -}
parseDuration :: Monad m => String -> m Duration
parseDuration = maybe parsefail (return . Duration) . go 0
where
go n [] = return n
go n s = do
num <- readish s :: Maybe Integer
case dropWhile isDigit s of
(c:rest) -> do
u <- M.lookup c unitmap
go (n + num * u) rest
_ -> return $ n + num
parsefail = fail "duration parse error; expected eg \"5m\" or \"1h5m\""
fromDuration :: Duration -> String
fromDuration Duration { durationSeconds = d }
| d == 0 = "0s"
| otherwise = concatMap showunit $ take 2 $ go [] units d
where
showunit (u, n) = show n ++ [u]
go c [] _ = reverse c
go c ((u, n):us) v =
let (q,r) = v `quotRem` n
in if q > 0
then go ((u, q):c) us r
else if null c
then go c us r
else reverse c
units :: [(Char, Integer)]
units =
[ ('y', ysecs)
, ('d', dsecs)
, ('h', hsecs)
, ('m', msecs)
, ('s', 1)
]
unitmap :: M.Map Char Integer
unitmap = M.fromList units
ysecs :: Integer
ysecs = dsecs * 365
dsecs :: Integer
dsecs = hsecs * 24
hsecs :: Integer
hsecs = msecs * 60
msecs :: Integer
msecs = 60
-- Durations cannot be negative.
instance Arbitrary Duration where
arbitrary = Duration <$> nonNegative arbitrary
prop_duration_roundtrips :: Duration -> Bool
prop_duration_roundtrips d = parseDuration (fromDuration d) == Just d
|
