1 -----------------------------------------------------------------------------
3 -- Module : System.Time
4 -- Copyright : (c) The University of Glasgow 2001
5 -- License : BSD-style (see the file libraries/core/LICENSE)
7 -- Maintainer : libraries@haskell.org
8 -- Stability : provisional
9 -- Portability : portable
11 -- The standard Time library.
13 -----------------------------------------------------------------------------
16 Haskell 98 Time of Day Library
17 ------------------------------
19 The Time library provides standard functionality for clock times,
20 including timezone information (i.e, the functionality of "time.h",
21 adapted to the Haskell environment), It follows RFC 1129 in its use of
22 Coordinated Universal Time (UTC).
24 2000/06/17 <michael.weber@post.rwth-aachen.de>:
26 * min./max. time diff currently is restricted to
27 [minBound::Int, maxBound::Int]
29 * surely other restrictions wrt. min/max bounds
35 `showTime' (used in `instance Show ClockTime') always prints time
36 converted to the local timezone (even if it is taken from
37 `(toClockTime . toUTCTime)'), whereas `calendarTimeToString'
38 honors the tzone & tz fields and prints UTC or whatever timezone
39 is stored inside CalendarTime.
41 Maybe `showTime' should be changed to use UTC, since it would
42 better correspond to the actual representation of `ClockTime'
43 (can be done by replacing localtime(3) by gmtime(3)).
47 * add proper handling of microsecs, currently, they're mostly
50 * `formatFOO' case of `%s' is currently broken...
54 * check for unusual date cases, like 1970/1/1 00:00h, and conversions
55 between different timezone's etc.
57 * check, what needs to be in the IO monad, the current situation
58 seems to be a bit inconsistent to me
60 * check whether `isDst = -1' works as expected on other arch's
63 * add functions to parse strings to `CalendarTime' (some day...)
65 * implement padding capabilities ("%_", "%-") in `formatFOO'
67 * add rfc822 timezone (+0200 is CEST) representation ("%z") in `formatFOO'
75 , ClockTime(..) -- non-standard, lib. report gives this as abstract
77 -- instance Show (non-standard)
82 , noTimeDiff -- non-standard (but useful when constructing TimeDiff vals.)
86 , normalizeTimeDiff -- non-standard
87 , timeDiffToString -- non-standard
88 , formatTimeDiff -- non-standard
94 , calendarTimeToString
105 import System.IO.Unsafe
110 -- One way to partition and give name to chunks of a year and a week:
113 = January | February | March | April
114 | May | June | July | August
115 | September | October | November | December
116 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
119 = Sunday | Monday | Tuesday | Wednesday
120 | Thursday | Friday | Saturday
121 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
123 -- @ClockTime@ is an abstract type, used for the internal clock time.
124 -- Clock times may be compared, converted to strings, or converted to an
125 -- external calendar time @CalendarTime@.
127 data ClockTime = TOD Integer -- Seconds since 00:00:00 on 1 Jan 1970
128 Integer -- Picoseconds with the specified second
131 -- When a ClockTime is shown, it is converted to a CalendarTime in the current
132 -- timezone and then printed. FIXME: This is arguably wrong, since we can't
133 -- get the current timezone without being in the IO monad.
135 instance Show ClockTime where
136 showsPrec _ t = showString (calendarTimeToString
137 (unsafePerformIO (toCalendarTime t)))
140 @CalendarTime@ is a user-readable and manipulable
141 representation of the internal $ClockTime$ type. The
142 numeric fields have the following ranges.
148 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
149 mon 0 .. 11 [Jan = 0, Dec = 11]
153 sec 0 .. 61 [Allows for two leap seconds]
154 picosec 0 .. (10^12)-1 [This could be over-precise?]
155 wday 0 .. 6 [Sunday = 0, Saturday = 6]
156 yday 0 .. 365 [364 in non-Leap years]
157 tz -43200 .. 43200 [Variation from UTC in seconds]
160 The {\em tzname} field is the name of the time zone. The {\em isdst}
161 field indicates whether Daylight Savings Time would be in effect.
172 ctPicosec :: Integer,
179 deriving (Eq,Ord,Read,Show)
181 -- The @TimeDiff@ type records the difference between two clock times in
182 -- a user-readable way.
192 tdPicosec :: Integer -- not standard
194 deriving (Eq,Ord,Read,Show)
196 noTimeDiff :: TimeDiff
197 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
199 -- -----------------------------------------------------------------------------
200 -- getClockTime returns the current time in its internal representation.
202 #if HAVE_GETTIMEOFDAY
204 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
205 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
206 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CTime
207 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CTime
208 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
212 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
214 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
215 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
216 return (TOD (fromIntegral sec) (fromIntegral msec * 1000000000))
218 #else /* use POSIX time() */
220 secs <- time nullPtr -- can't fail, according to POSIX
221 return (TOD (fromIntegral secs) 0)
225 -- -----------------------------------------------------------------------------
226 -- addToClockTime d t adds a time difference d and a
227 -- clock time t to yield a new clock time. The difference d
228 -- may be either positive or negative. diffClockTimes t1 t2 returns
229 -- the difference between two clock times t1 and t2 as a TimeDiff.
231 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
232 addToClockTime (TimeDiff year mon day hour min sec psec)
235 sec_diff = toInteger sec +
237 3600 * toInteger hour +
238 24 * 3600 * toInteger day
239 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
241 new_mon = fromEnum (ctMonth cal) + r_mon
243 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
244 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
245 | otherwise = (toEnum new_mon, 0)
247 (r_yr, r_mon) = mon `quotRem` 12
249 year' = ctYear cal + year + r_yr + yr_diff
251 toClockTime cal{ctMonth=month', ctYear=year'}
253 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
254 -- diffClockTimes is meant to be the dual to `addToClockTime'.
255 -- If you want to have the TimeDiff properly splitted, use
256 -- `normalizeTimeDiff' on this function's result
258 -- CAVEAT: see comment of normalizeTimeDiff
259 diffClockTimes (TOD sa pa) (TOD sb pb) =
260 noTimeDiff{ tdSec = fromIntegral (sa - sb)
261 -- FIXME: can handle just 68 years...
262 , tdPicosec = pa - pb
266 normalizeTimeDiff :: TimeDiff -> TimeDiff
267 -- FIXME: handle psecs properly
268 -- FIXME: ?should be called by formatTimeDiff automagically?
270 -- when applied to something coming out of `diffClockTimes', you loose
271 -- the duality to `addToClockTime', since a year does not always have
274 -- apply this function as late as possible to prevent those "rounding"
276 normalizeTimeDiff td =
283 + 365 * tdYear td))))
285 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
286 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
287 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
288 (diffHours, rest4) = rest3 `quotRem` 3600
289 (diffMins, diffSecs) = rest4 `quotRem` 60
291 td{ tdYear = diffYears
292 , tdMonth = diffMonths
299 -- -----------------------------------------------------------------------------
300 -- How do we deal with timezones on this architecture?
302 -- The POSIX way to do it is through the global variable tzname[].
303 -- But that's crap, so we do it The BSD Way if we can: namely use the
304 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
306 zone :: Ptr CTm -> IO (Ptr CChar)
307 gmtoff :: Ptr CTm -> IO CLong
309 zone x = (#peek struct tm,tm_zone) x
310 gmtoff x = (#peek struct tm,tm_gmtoff) x
312 #else /* ! HAVE_TM_ZONE */
313 # if HAVE_TZNAME || defined(_WIN32)
314 # if cygwin32_TARGET_OS
315 # define tzname _tzname
317 # ifndef mingw32_TARGET_OS
318 foreign import ccall unsafe "&tzname" tzname :: Ptr (Ptr CChar)
320 foreign import ccall unsafe "__hscore_timezone" timezone :: Ptr CLong
321 foreign import ccall unsafe "__hscore_tzname" tzname :: Ptr (Ptr CChar)
324 dst <- (#peek struct tm,tm_isdst) x
325 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
326 # else /* ! HAVE_TZNAME */
327 -- We're in trouble. If you should end up here, please report this as a bug.
328 # error "Don't know how to get at timezone name on your OS."
329 # endif /* ! HAVE_TZNAME */
331 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
333 foreign import ccall "&altzone" altzone :: Ptr CTime
334 foreign import ccall "&timezone" timezone :: Ptr CTime
336 dst <- (#peek struct tm,tm_isdst) x
337 tz <- if dst then peek altzone else peek timezone
338 return (fromIntegral tz)
339 # define GMTOFF(x) (((struct tm *)x)->tm_isdst ? altzone : timezone )
340 # else /* ! HAVE_ALTZONE */
342 #if !defined(mingw32_TARGET_OS)
343 foreign import ccall unsafe "timezone" timezone :: Ptr CLong
346 -- Assume that DST offset is 1 hour ...
348 dst <- (#peek struct tm,tm_isdst) x
350 if dst then return (fromIntegral tz - 3600) else return tz
351 # endif /* ! HAVE_ALTZONE */
352 #endif /* ! HAVE_TM_ZONE */
354 -- -----------------------------------------------------------------------------
355 -- toCalendarTime t converts t to a local time, modified by
356 -- the current timezone and daylight savings time settings. toUTCTime
357 -- t converts t into UTC time. toClockTime l converts l into the
358 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
362 toCalendarTime :: ClockTime -> IO CalendarTime
364 toCalendarTime = clockToCalendarTime_reentrant (throwAwayReturnPointer localtime_r) False
366 toCalendarTime = clockToCalendarTime_static localtime False
369 toUTCTime :: ClockTime -> CalendarTime
371 toUTCTime = unsafePerformIO . clockToCalendarTime_reentrant (throwAwayReturnPointer gmtime_r) True
373 toUTCTime = unsafePerformIO . clockToCalendarTime_static gmtime True
376 throwAwayReturnPointer :: (Ptr CTime -> Ptr CTm -> IO (Ptr CTm))
377 -> (Ptr CTime -> Ptr CTm -> IO ( ))
378 throwAwayReturnPointer fun x y = fun x y >> return ()
380 clockToCalendarTime_static :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
382 clockToCalendarTime_static fun is_utc (TOD secs psec) = do
383 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
384 p_tm <- fun p_timer -- can't fail, according to POSIX
385 clockToCalendarTime_aux is_utc p_tm psec
387 clockToCalendarTime_reentrant :: (Ptr CTime -> Ptr CTm -> IO ()) -> Bool -> ClockTime
389 clockToCalendarTime_reentrant fun is_utc (TOD secs psec) = do
390 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
391 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
393 clockToCalendarTime_aux is_utc p_tm psec
395 clockToCalendarTime_aux :: Bool -> Ptr CTm -> Integer -> IO CalendarTime
396 clockToCalendarTime_aux is_utc p_tm psec = do
397 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
398 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
399 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
400 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
401 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
402 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
403 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
404 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
405 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
409 tzname <- peekCString zone
411 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
412 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
415 (1900 + fromIntegral year)
422 (toEnum (fromIntegral wday))
424 (if is_utc then "UTC" else tzname)
425 (if is_utc then 0 else fromIntegral tz)
426 (if is_utc then False else isdst /= 0))
429 toClockTime :: CalendarTime -> ClockTime
430 toClockTime (CalendarTime year mon mday hour min sec psec
431 _wday _yday _tzname tz isdst) =
433 -- `isDst' causes the date to be wrong by one hour...
434 -- FIXME: check, whether this works on other arch's than Linux, too...
436 -- so we set it to (-1) (means `unknown') and let `mktime' determine
438 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
440 if psec < 0 || psec > 999999999999 then
441 error "Time.toClockTime: picoseconds out of range"
442 else if tz < -43200 || tz > 43200 then
443 error "Time.toClockTime: timezone offset out of range"
446 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
447 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
448 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
449 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
450 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
451 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
452 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
453 (#poke struct tm,tm_isdst) p_tm isDst
454 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
457 -- mktime expects its argument to be in the local timezone, but
458 -- toUTCTime makes UTC-encoded CalendarTime's ...
460 -- Since there is no any_tz_struct_tm-to-time_t conversion
461 -- function, we have to fake one... :-) If not in all, it works in
462 -- most cases (before, it was the other way round...)
464 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
465 -- to compensate, we add the timezone difference to mktime's
468 gmtoff <- gmtoff p_tm
469 let res = fromIntegral t - tz + fromIntegral gmtoff
470 return (TOD (fromIntegral res) psec)
472 -- -----------------------------------------------------------------------------
473 -- Converting time values to strings.
475 calendarTimeToString :: CalendarTime -> String
476 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
478 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
479 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
480 wday yday tzname _ _) =
482 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
483 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
484 doFmt ('%':c:cs) = decode c ++ doFmt cs
485 doFmt (c:cs) = c : doFmt cs
488 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
489 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
490 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
491 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
492 decode 'h' = snd (months l !! fromEnum mon) -- ditto
493 decode 'C' = show2 (year `quot` 100) -- century
494 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
495 decode 'D' = doFmt "%m/%d/%y"
496 decode 'd' = show2 day -- day of the month
497 decode 'e' = show2' day -- ditto, padded
498 decode 'H' = show2 hour -- hours, 24-hour clock, padded
499 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
500 decode 'j' = show3 yday -- day of the year
501 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
502 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
503 decode 'M' = show2 min -- minutes
504 decode 'm' = show2 (fromEnum mon+1) -- numeric month
506 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
507 decode 'R' = doFmt "%H:%M"
508 decode 'r' = doFmt (time12Fmt l)
509 decode 'T' = doFmt "%H:%M:%S"
511 decode 'S' = show2 sec -- seconds
512 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
513 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
514 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
515 if n == 0 then 7 else n)
516 decode 'V' = -- week number (as per ISO-8601.)
517 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
518 (yday + 7 - if fromEnum wday > 0 then
519 fromEnum wday - 1 else 6) `divMod` 7
520 in show2 (if days >= 4 then
522 else if week == 0 then 53 else week)
524 decode 'W' = -- week number, weeks starting on monday
525 show2 ((yday + 7 - if fromEnum wday > 0 then
526 fromEnum wday - 1 else 6) `div` 7)
527 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
528 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
529 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
530 decode 'Y' = show year -- year, including century.
531 decode 'y' = show2 (year `rem` 100) -- year, within century.
532 decode 'Z' = tzname -- timezone name
537 show2, show2', show3 :: Int -> String
539 | x' < 10 = '0': show x'
540 | otherwise = show x'
541 where x' = x `rem` 100
544 | x' < 10 = ' ': show x'
545 | otherwise = show x'
546 where x' = x `rem` 100
548 show3 x = show (x `quot` 100) ++ show2 (x `rem` 100)
549 where x' = x `rem` 1000
552 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
554 -- Useful extensions for formatting TimeDiffs.
556 timeDiffToString :: TimeDiff -> String
557 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
559 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
560 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
564 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
565 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
566 doFmt ('%':c:cs) = decode c ++ doFmt cs
567 doFmt (c:cs) = c : doFmt cs
571 'B' -> fst (months l !! fromEnum month)
572 'b' -> snd (months l !! fromEnum month)
573 'h' -> snd (months l !! fromEnum month)
574 'c' -> defaultTimeDiffFmt td
575 'C' -> show2 (year `quot` 100)
576 'D' -> doFmt "%m/%d/%y"
580 'I' -> show2 (to12 hour)
582 'l' -> show2' (to12 hour)
584 'm' -> show2 (fromEnum month + 1)
586 'p' -> (if hour < 12 then fst else snd) (amPm l)
588 'r' -> doFmt (time12Fmt l)
589 'T' -> doFmt "%H:%M:%S"
592 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
593 'X' -> doFmt (timeFmt l)
594 'x' -> doFmt (dateFmt l)
596 'y' -> show2 (year `rem` 100)
600 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
601 foldr (\ (v,s) rest ->
603 then show v ++ ' ':(addS v s)
604 ++ if null rest then "" else ", "
608 (zip [year, month, day, hour, min, sec] (intervals l))
610 addS v s = if abs v == 1 then fst s else snd s
613 -- -----------------------------------------------------------------------------
614 -- Foreign time interface (POSIX)
616 type CTm = () -- struct tm
619 foreign import ccall unsafe localtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
621 foreign import ccall unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
624 foreign import ccall unsafe gmtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
626 foreign import ccall unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
628 foreign import ccall unsafe mktime :: Ptr CTm -> IO CTime
629 foreign import ccall unsafe time :: Ptr CTime -> IO CTime
631 #if HAVE_GETTIMEOFDAY
633 foreign import ccall unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
638 #ifndef mingw32_TARGET_OS
639 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO CInt
641 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO ()