1 -----------------------------------------------------------------------------
3 -- Module : System.Time
4 -- Copyright : (c) The University of Glasgow 2001
5 -- License : BSD-style (see the file libraries/base/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
99 #ifdef __GLASGOW_HASKELL__
105 #define HAVE_TM_ZONE 1
113 import System.IO.Unsafe
116 import Hugs.Time ( getClockTimePrim, toCalTimePrim, toClockTimePrim )
122 -- One way to partition and give name to chunks of a year and a week:
125 = January | February | March | April
126 | May | June | July | August
127 | September | October | November | December
128 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
131 = Sunday | Monday | Tuesday | Wednesday
132 | Thursday | Friday | Saturday
133 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
135 -- @ClockTime@ is an abstract type, used for the internal clock time.
136 -- Clock times may be compared, converted to strings, or converted to an
137 -- external calendar time @CalendarTime@.
139 data ClockTime = TOD Integer -- Seconds since 00:00:00 on 1 Jan 1970
140 Integer -- Picoseconds with the specified second
143 -- When a ClockTime is shown, it is converted to a CalendarTime in the current
144 -- timezone and then printed. FIXME: This is arguably wrong, since we can't
145 -- get the current timezone without being in the IO monad.
147 instance Show ClockTime where
148 showsPrec _ t = showString (calendarTimeToString
149 (unsafePerformIO (toCalendarTime t)))
152 @CalendarTime@ is a user-readable and manipulable
153 representation of the internal $ClockTime$ type. The
154 numeric fields have the following ranges.
160 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
161 mon 0 .. 11 [Jan = 0, Dec = 11]
165 sec 0 .. 61 [Allows for two leap seconds]
166 picosec 0 .. (10^12)-1 [This could be over-precise?]
167 wday 0 .. 6 [Sunday = 0, Saturday = 6]
168 yday 0 .. 365 [364 in non-Leap years]
169 tz -43200 .. 43200 [Variation from UTC in seconds]
172 The {\em tzname} field is the name of the time zone. The {\em isdst}
173 field indicates whether Daylight Savings Time would be in effect.
184 ctPicosec :: Integer,
191 deriving (Eq,Ord,Read,Show)
193 -- The @TimeDiff@ type records the difference between two clock times in
194 -- a user-readable way.
204 tdPicosec :: Integer -- not standard
206 deriving (Eq,Ord,Read,Show)
208 noTimeDiff :: TimeDiff
209 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
211 -- -----------------------------------------------------------------------------
212 -- getClockTime returns the current time in its internal representation.
214 getClockTime :: IO ClockTime
217 (sec,usec) <- getClockTimePrim
218 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
220 #elif HAVE_GETTIMEOFDAY
222 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
223 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
224 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CTime
225 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CTime
226 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
230 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
232 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
233 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
234 return (TOD (fromIntegral sec) (fromIntegral msec * 1000000000))
236 #else /* use POSIX time() */
238 secs <- time nullPtr -- can't fail, according to POSIX
239 return (TOD (fromIntegral secs) 0)
243 -- -----------------------------------------------------------------------------
244 -- addToClockTime d t adds a time difference d and a
245 -- clock time t to yield a new clock time. The difference d
246 -- may be either positive or negative. diffClockTimes t1 t2 returns
247 -- the difference between two clock times t1 and t2 as a TimeDiff.
249 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
250 addToClockTime (TimeDiff year mon day hour min sec psec)
253 sec_diff = toInteger sec +
255 3600 * toInteger hour +
256 24 * 3600 * toInteger day
257 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
259 new_mon = fromEnum (ctMonth cal) + r_mon
263 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
264 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
265 | otherwise = (toEnum new_mon, 0)
267 (r_yr, r_mon) = mon `quotRem` 12
269 year' = ctYear cal + year + r_yr + yr_diff
271 toClockTime cal{ctMonth=month', ctYear=year'}
273 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
274 -- diffClockTimes is meant to be the dual to `addToClockTime'.
275 -- If you want to have the TimeDiff properly splitted, use
276 -- `normalizeTimeDiff' on this function's result
278 -- CAVEAT: see comment of normalizeTimeDiff
279 diffClockTimes (TOD sa pa) (TOD sb pb) =
280 noTimeDiff{ tdSec = fromIntegral (sa - sb)
281 -- FIXME: can handle just 68 years...
282 , tdPicosec = pa - pb
286 normalizeTimeDiff :: TimeDiff -> TimeDiff
287 -- FIXME: handle psecs properly
288 -- FIXME: ?should be called by formatTimeDiff automagically?
290 -- when applied to something coming out of `diffClockTimes', you loose
291 -- the duality to `addToClockTime', since a year does not always have
294 -- apply this function as late as possible to prevent those "rounding"
296 normalizeTimeDiff td =
303 + 365 * tdYear td))))
305 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
306 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
307 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
308 (diffHours, rest4) = rest3 `quotRem` 3600
309 (diffMins, diffSecs) = rest4 `quotRem` 60
311 td{ tdYear = diffYears
312 , tdMonth = diffMonths
320 -- -----------------------------------------------------------------------------
321 -- How do we deal with timezones on this architecture?
323 -- The POSIX way to do it is through the global variable tzname[].
324 -- But that's crap, so we do it The BSD Way if we can: namely use the
325 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
327 zone :: Ptr CTm -> IO (Ptr CChar)
328 gmtoff :: Ptr CTm -> IO CLong
330 zone x = (#peek struct tm,tm_zone) x
331 gmtoff x = (#peek struct tm,tm_gmtoff) x
333 #else /* ! HAVE_TM_ZONE */
334 # if HAVE_TZNAME || defined(_WIN32)
335 # if cygwin32_TARGET_OS
336 # define tzname _tzname
338 # ifndef mingw32_TARGET_OS
339 foreign import ccall unsafe "&tzname" tzname :: Ptr (Ptr CChar)
341 foreign import ccall unsafe "__hscore_timezone" timezone :: Ptr CLong
342 foreign import ccall unsafe "__hscore_tzname" tzname :: Ptr (Ptr CChar)
345 dst <- (#peek struct tm,tm_isdst) x
346 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
347 # else /* ! HAVE_TZNAME */
348 -- We're in trouble. If you should end up here, please report this as a bug.
349 # error "Don't know how to get at timezone name on your OS."
350 # endif /* ! HAVE_TZNAME */
352 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
353 # if HAVE_DECL_ALTZONE
354 foreign import ccall "&altzone" altzone :: Ptr CTime
355 foreign import ccall "&timezone" timezone :: Ptr CTime
357 dst <- (#peek struct tm,tm_isdst) x
358 tz <- if dst then peek altzone else peek timezone
359 return (-fromIntegral tz)
360 # else /* ! HAVE_DECL_ALTZONE */
362 #if !defined(mingw32_TARGET_OS)
363 foreign import ccall unsafe "timezone" timezone :: Ptr CLong
366 -- Assume that DST offset is 1 hour ...
368 dst <- (#peek struct tm,tm_isdst) x
370 -- According to the documentation for tzset(),
371 -- http://www.opengroup.org/onlinepubs/007908799/xsh/tzset.html
372 -- timezone offsets are > 0 west of the Prime Meridian.
374 -- This module assumes the interpretation of tm_gmtoff, i.e., offsets
375 -- are > 0 East of the Prime Meridian, so flip the sign.
376 return (- (if dst then (fromIntegral tz - 3600) else tz))
377 # endif /* ! HAVE_DECL_ALTZONE */
378 #endif /* ! HAVE_TM_ZONE */
379 #endif /* ! __HUGS__ */
381 -- -----------------------------------------------------------------------------
382 -- toCalendarTime t converts t to a local time, modified by
383 -- the current timezone and daylight savings time settings. toUTCTime
384 -- t converts t into UTC time. toClockTime l converts l into the
385 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
389 toCalendarTime :: ClockTime -> IO CalendarTime
391 toCalendarTime = toCalTime False
392 #elif HAVE_LOCALTIME_R
393 toCalendarTime = clockToCalendarTime_reentrant (throwAwayReturnPointer localtime_r) False
395 toCalendarTime = clockToCalendarTime_static localtime False
398 toUTCTime :: ClockTime -> CalendarTime
400 toUTCTime = unsafePerformIO . toCalTime True
402 toUTCTime = unsafePerformIO . clockToCalendarTime_reentrant (throwAwayReturnPointer gmtime_r) True
404 toUTCTime = unsafePerformIO . clockToCalendarTime_static gmtime True
408 toCalTime :: Bool -> ClockTime -> IO CalendarTime
409 toCalTime toUTC (TOD s psecs)
410 | (s > fromIntegral (maxBound :: Int)) ||
411 (s < fromIntegral (minBound :: Int))
412 = error ((if toUTC then "toUTCTime: " else "toCalendarTime: ") ++
413 "clock secs out of range")
415 (sec,min,hour,mday,mon,year,wday,yday,isdst,zone,off) <-
416 toCalTimePrim (if toUTC then 1 else 0) (fromIntegral s)
417 return (CalendarTime{ ctYear=1900+year
426 , ctTZName=(if toUTC then "UTC" else zone)
427 , ctTZ=(if toUTC then 0 else off)
428 , ctIsDST=not toUTC && (isdst/=0)
430 #else /* ! __HUGS__ */
431 throwAwayReturnPointer :: (Ptr CTime -> Ptr CTm -> IO (Ptr CTm))
432 -> (Ptr CTime -> Ptr CTm -> IO ( ))
433 throwAwayReturnPointer fun x y = fun x y >> return ()
435 clockToCalendarTime_static :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
437 clockToCalendarTime_static fun is_utc (TOD secs psec) = do
438 with (fromIntegral secs :: CTime) $ \ p_timer -> do
439 p_tm <- fun p_timer -- can't fail, according to POSIX
440 clockToCalendarTime_aux is_utc p_tm psec
442 clockToCalendarTime_reentrant :: (Ptr CTime -> Ptr CTm -> IO ()) -> Bool -> ClockTime
444 clockToCalendarTime_reentrant fun is_utc (TOD secs psec) = do
445 with (fromIntegral secs :: CTime) $ \ p_timer -> do
446 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
448 clockToCalendarTime_aux is_utc p_tm psec
450 clockToCalendarTime_aux :: Bool -> Ptr CTm -> Integer -> IO CalendarTime
451 clockToCalendarTime_aux is_utc p_tm psec = do
452 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
453 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
454 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
455 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
456 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
457 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
458 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
459 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
460 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
464 tzname <- peekCString zone
466 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
467 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
470 (1900 + fromIntegral year)
477 (toEnum (fromIntegral wday))
479 (if is_utc then "UTC" else tzname)
480 (if is_utc then 0 else fromIntegral tz)
481 (if is_utc then False else isdst /= 0))
482 #endif /* ! __HUGS__ */
484 toClockTime :: CalendarTime -> ClockTime
486 toClockTime (CalendarTime yr mon mday hour min sec psec
487 _wday _yday _tzname tz _isdst) =
489 s <- toClockTimePrim (yr-1900) (fromEnum mon) mday hour min sec tz
490 return (TOD (fromIntegral s) psec)
491 #else /* ! __HUGS__ */
492 toClockTime (CalendarTime year mon mday hour min sec psec
493 _wday _yday _tzname tz isdst) =
495 -- `isDst' causes the date to be wrong by one hour...
496 -- FIXME: check, whether this works on other arch's than Linux, too...
498 -- so we set it to (-1) (means `unknown') and let `mktime' determine
500 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
502 if psec < 0 || psec > 999999999999 then
503 error "Time.toClockTime: picoseconds out of range"
504 else if tz < -43200 || tz > 43200 then
505 error "Time.toClockTime: timezone offset out of range"
508 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
509 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
510 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
511 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
512 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
513 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
514 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
515 (#poke struct tm,tm_isdst) p_tm isDst
516 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
519 -- mktime expects its argument to be in the local timezone, but
520 -- toUTCTime makes UTC-encoded CalendarTime's ...
522 -- Since there is no any_tz_struct_tm-to-time_t conversion
523 -- function, we have to fake one... :-) If not in all, it works in
524 -- most cases (before, it was the other way round...)
526 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
527 -- to compensate, we add the timezone difference to mktime's
530 gmtoff <- gmtoff p_tm
531 let res = fromIntegral t - tz + fromIntegral gmtoff
532 return (TOD (fromIntegral res) psec)
533 #endif /* ! __HUGS__ */
535 -- -----------------------------------------------------------------------------
536 -- Converting time values to strings.
538 calendarTimeToString :: CalendarTime -> String
539 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
541 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
542 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
543 wday yday tzname _ _) =
545 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
546 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
547 doFmt ('%':c:cs) = decode c ++ doFmt cs
548 doFmt (c:cs) = c : doFmt cs
551 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
552 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
553 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
554 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
555 decode 'h' = snd (months l !! fromEnum mon) -- ditto
556 decode 'C' = show2 (year `quot` 100) -- century
557 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
558 decode 'D' = doFmt "%m/%d/%y"
559 decode 'd' = show2 day -- day of the month
560 decode 'e' = show2' day -- ditto, padded
561 decode 'H' = show2 hour -- hours, 24-hour clock, padded
562 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
563 decode 'j' = show3 yday -- day of the year
564 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
565 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
566 decode 'M' = show2 min -- minutes
567 decode 'm' = show2 (fromEnum mon+1) -- numeric month
569 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
570 decode 'R' = doFmt "%H:%M"
571 decode 'r' = doFmt (time12Fmt l)
572 decode 'T' = doFmt "%H:%M:%S"
574 decode 'S' = show2 sec -- seconds
575 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
576 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
577 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
578 if n == 0 then 7 else n)
579 decode 'V' = -- week number (as per ISO-8601.)
580 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
581 (yday + 7 - if fromEnum wday > 0 then
582 fromEnum wday - 1 else 6) `divMod` 7
583 in show2 (if days >= 4 then
585 else if week == 0 then 53 else week)
587 decode 'W' = -- week number, weeks starting on monday
588 show2 ((yday + 7 - if fromEnum wday > 0 then
589 fromEnum wday - 1 else 6) `div` 7)
590 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
591 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
592 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
593 decode 'Y' = show year -- year, including century.
594 decode 'y' = show2 (year `rem` 100) -- year, within century.
595 decode 'Z' = tzname -- timezone name
600 show2, show2', show3 :: Int -> String
602 | x' < 10 = '0': show x'
603 | otherwise = show x'
604 where x' = x `rem` 100
607 | x' < 10 = ' ': show x'
608 | otherwise = show x'
609 where x' = x `rem` 100
611 show3 x = show (x `quot` 100) ++ show2 (x `rem` 100)
612 where x' = x `rem` 1000
615 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
617 -- Useful extensions for formatting TimeDiffs.
619 timeDiffToString :: TimeDiff -> String
620 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
622 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
623 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
627 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
628 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
629 doFmt ('%':c:cs) = decode c ++ doFmt cs
630 doFmt (c:cs) = c : doFmt cs
634 'B' -> fst (months l !! fromEnum month)
635 'b' -> snd (months l !! fromEnum month)
636 'h' -> snd (months l !! fromEnum month)
637 'c' -> defaultTimeDiffFmt td
638 'C' -> show2 (year `quot` 100)
639 'D' -> doFmt "%m/%d/%y"
643 'I' -> show2 (to12 hour)
645 'l' -> show2' (to12 hour)
647 'm' -> show2 (fromEnum month + 1)
649 'p' -> (if hour < 12 then fst else snd) (amPm l)
651 'r' -> doFmt (time12Fmt l)
652 'T' -> doFmt "%H:%M:%S"
655 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
656 'X' -> doFmt (timeFmt l)
657 'x' -> doFmt (dateFmt l)
659 'y' -> show2 (year `rem` 100)
663 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
664 foldr (\ (v,s) rest ->
666 then show v ++ ' ':(addS v s)
667 ++ if null rest then "" else ", "
671 (zip [year, month, day, hour, min, sec] (intervals l))
673 addS v s = if abs v == 1 then fst s else snd s
676 -- -----------------------------------------------------------------------------
677 -- Foreign time interface (POSIX)
679 type CTm = () -- struct tm
682 foreign import ccall unsafe localtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
684 foreign import ccall unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
687 foreign import ccall unsafe gmtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
689 foreign import ccall unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
691 foreign import ccall unsafe mktime :: Ptr CTm -> IO CTime
692 foreign import ccall unsafe time :: Ptr CTime -> IO CTime
694 #if HAVE_GETTIMEOFDAY
696 foreign import ccall unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
701 #ifndef mingw32_TARGET_OS
702 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO CInt
704 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO ()
707 #endif /* ! __HUGS__ */