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
107 import System.IO.Unsafe
110 import Hugs.Time ( getClockTimePrim, toCalTimePrim, toClockTimePrim )
116 -- One way to partition and give name to chunks of a year and a week:
119 = January | February | March | April
120 | May | June | July | August
121 | September | October | November | December
122 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
125 = Sunday | Monday | Tuesday | Wednesday
126 | Thursday | Friday | Saturday
127 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
129 -- @ClockTime@ is an abstract type, used for the internal clock time.
130 -- Clock times may be compared, converted to strings, or converted to an
131 -- external calendar time @CalendarTime@.
133 data ClockTime = TOD Integer -- Seconds since 00:00:00 on 1 Jan 1970
134 Integer -- Picoseconds with the specified second
137 -- When a ClockTime is shown, it is converted to a CalendarTime in the current
138 -- timezone and then printed. FIXME: This is arguably wrong, since we can't
139 -- get the current timezone without being in the IO monad.
141 instance Show ClockTime where
142 showsPrec _ t = showString (calendarTimeToString
143 (unsafePerformIO (toCalendarTime t)))
146 @CalendarTime@ is a user-readable and manipulable
147 representation of the internal $ClockTime$ type. The
148 numeric fields have the following ranges.
154 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
155 mon 0 .. 11 [Jan = 0, Dec = 11]
159 sec 0 .. 61 [Allows for two leap seconds]
160 picosec 0 .. (10^12)-1 [This could be over-precise?]
161 wday 0 .. 6 [Sunday = 0, Saturday = 6]
162 yday 0 .. 365 [364 in non-Leap years]
163 tz -43200 .. 43200 [Variation from UTC in seconds]
166 The {\em tzname} field is the name of the time zone. The {\em isdst}
167 field indicates whether Daylight Savings Time would be in effect.
178 ctPicosec :: Integer,
185 deriving (Eq,Ord,Read,Show)
187 -- The @TimeDiff@ type records the difference between two clock times in
188 -- a user-readable way.
198 tdPicosec :: Integer -- not standard
200 deriving (Eq,Ord,Read,Show)
202 noTimeDiff :: TimeDiff
203 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
205 -- -----------------------------------------------------------------------------
206 -- getClockTime returns the current time in its internal representation.
208 getClockTime :: IO ClockTime
211 (sec,usec) <- getClockTimePrim
212 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
214 #elif HAVE_GETTIMEOFDAY
216 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
217 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
218 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CTime
219 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CTime
220 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
224 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
226 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
227 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
228 return (TOD (fromIntegral sec) (fromIntegral msec * 1000000000))
230 #else /* use POSIX time() */
232 secs <- time nullPtr -- can't fail, according to POSIX
233 return (TOD (fromIntegral secs) 0)
237 -- -----------------------------------------------------------------------------
238 -- addToClockTime d t adds a time difference d and a
239 -- clock time t to yield a new clock time. The difference d
240 -- may be either positive or negative. diffClockTimes t1 t2 returns
241 -- the difference between two clock times t1 and t2 as a TimeDiff.
243 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
244 addToClockTime (TimeDiff year mon day hour min sec psec)
247 sec_diff = toInteger sec +
249 3600 * toInteger hour +
250 24 * 3600 * toInteger day
251 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
253 new_mon = fromEnum (ctMonth cal) + r_mon
255 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
256 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
257 | otherwise = (toEnum new_mon, 0)
259 (r_yr, r_mon) = mon `quotRem` 12
261 year' = ctYear cal + year + r_yr + yr_diff
263 toClockTime cal{ctMonth=month', ctYear=year'}
265 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
266 -- diffClockTimes is meant to be the dual to `addToClockTime'.
267 -- If you want to have the TimeDiff properly splitted, use
268 -- `normalizeTimeDiff' on this function's result
270 -- CAVEAT: see comment of normalizeTimeDiff
271 diffClockTimes (TOD sa pa) (TOD sb pb) =
272 noTimeDiff{ tdSec = fromIntegral (sa - sb)
273 -- FIXME: can handle just 68 years...
274 , tdPicosec = pa - pb
278 normalizeTimeDiff :: TimeDiff -> TimeDiff
279 -- FIXME: handle psecs properly
280 -- FIXME: ?should be called by formatTimeDiff automagically?
282 -- when applied to something coming out of `diffClockTimes', you loose
283 -- the duality to `addToClockTime', since a year does not always have
286 -- apply this function as late as possible to prevent those "rounding"
288 normalizeTimeDiff td =
295 + 365 * tdYear td))))
297 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
298 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
299 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
300 (diffHours, rest4) = rest3 `quotRem` 3600
301 (diffMins, diffSecs) = rest4 `quotRem` 60
303 td{ tdYear = diffYears
304 , tdMonth = diffMonths
312 -- -----------------------------------------------------------------------------
313 -- How do we deal with timezones on this architecture?
315 -- The POSIX way to do it is through the global variable tzname[].
316 -- But that's crap, so we do it The BSD Way if we can: namely use the
317 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
319 zone :: Ptr CTm -> IO (Ptr CChar)
320 gmtoff :: Ptr CTm -> IO CLong
322 zone x = (#peek struct tm,tm_zone) x
323 gmtoff x = (#peek struct tm,tm_gmtoff) x
325 #else /* ! HAVE_TM_ZONE */
326 # if HAVE_TZNAME || defined(_WIN32)
327 # if cygwin32_TARGET_OS
328 # define tzname _tzname
330 # ifndef mingw32_TARGET_OS
331 foreign import ccall unsafe "&tzname" tzname :: Ptr (Ptr CChar)
333 foreign import ccall unsafe "__hscore_timezone" timezone :: Ptr CLong
334 foreign import ccall unsafe "__hscore_tzname" tzname :: Ptr (Ptr CChar)
337 dst <- (#peek struct tm,tm_isdst) x
338 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
339 # else /* ! HAVE_TZNAME */
340 -- We're in trouble. If you should end up here, please report this as a bug.
341 # error "Don't know how to get at timezone name on your OS."
342 # endif /* ! HAVE_TZNAME */
344 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
345 # if HAVE_DECL_ALTZONE
346 foreign import ccall "&altzone" altzone :: Ptr CTime
347 foreign import ccall "&timezone" timezone :: Ptr CTime
349 dst <- (#peek struct tm,tm_isdst) x
350 tz <- if dst then peek altzone else peek timezone
351 return (-fromIntegral tz)
352 # else /* ! HAVE_DECL_ALTZONE */
354 #if !defined(mingw32_TARGET_OS)
355 foreign import ccall unsafe "timezone" timezone :: Ptr CLong
358 -- Assume that DST offset is 1 hour ...
360 dst <- (#peek struct tm,tm_isdst) x
362 -- According to the documentation for tzset(),
363 -- http://www.opengroup.org/onlinepubs/007908799/xsh/tzset.html
364 -- timezone offsets are > 0 west of the Prime Meridian.
366 -- This module assumes the interpretation of tm_gmtoff, i.e., offsets
367 -- are > 0 East of the Prime Meridian, so flip the sign.
368 return (- (if dst then (fromIntegral tz - 3600) else tz))
369 # endif /* ! HAVE_DECL_ALTZONE */
370 #endif /* ! HAVE_TM_ZONE */
371 #endif /* ! __HUGS__ */
373 -- -----------------------------------------------------------------------------
374 -- toCalendarTime t converts t to a local time, modified by
375 -- the current timezone and daylight savings time settings. toUTCTime
376 -- t converts t into UTC time. toClockTime l converts l into the
377 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
381 toCalendarTime :: ClockTime -> IO CalendarTime
383 toCalendarTime = toCalTime False
384 #elif HAVE_LOCALTIME_R
385 toCalendarTime = clockToCalendarTime_reentrant (throwAwayReturnPointer localtime_r) False
387 toCalendarTime = clockToCalendarTime_static localtime False
390 toUTCTime :: ClockTime -> CalendarTime
392 toUTCTime = unsafePerformIO . toCalTime True
394 toUTCTime = unsafePerformIO . clockToCalendarTime_reentrant (throwAwayReturnPointer gmtime_r) True
396 toUTCTime = unsafePerformIO . clockToCalendarTime_static gmtime True
400 toCalTime :: Bool -> ClockTime -> IO CalendarTime
401 toCalTime toUTC (TOD s psecs)
402 | (s > fromIntegral (maxBound :: Int)) ||
403 (s < fromIntegral (minBound :: Int))
404 = error ((if toUTC then "toUTCTime: " else "toCalendarTime: ") ++
405 "clock secs out of range")
407 (sec,min,hour,mday,mon,year,wday,yday,isdst,zone,off) <-
408 toCalTimePrim (if toUTC then 1 else 0) (fromIntegral s)
409 return (CalendarTime{ ctYear=1900+year
418 , ctTZName=(if toUTC then "UTC" else zone)
419 , ctTZ=(if toUTC then 0 else off)
420 , ctIsDST=not toUTC && (isdst/=0)
422 #else /* ! __HUGS__ */
423 throwAwayReturnPointer :: (Ptr CTime -> Ptr CTm -> IO (Ptr CTm))
424 -> (Ptr CTime -> Ptr CTm -> IO ( ))
425 throwAwayReturnPointer fun x y = fun x y >> return ()
427 clockToCalendarTime_static :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
429 clockToCalendarTime_static fun is_utc (TOD secs psec) = do
430 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
431 p_tm <- fun p_timer -- can't fail, according to POSIX
432 clockToCalendarTime_aux is_utc p_tm psec
434 clockToCalendarTime_reentrant :: (Ptr CTime -> Ptr CTm -> IO ()) -> Bool -> ClockTime
436 clockToCalendarTime_reentrant fun is_utc (TOD secs psec) = do
437 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
438 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
440 clockToCalendarTime_aux is_utc p_tm psec
442 clockToCalendarTime_aux :: Bool -> Ptr CTm -> Integer -> IO CalendarTime
443 clockToCalendarTime_aux is_utc p_tm psec = do
444 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
445 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
446 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
447 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
448 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
449 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
450 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
451 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
452 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
456 tzname <- peekCString zone
458 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
459 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
462 (1900 + fromIntegral year)
469 (toEnum (fromIntegral wday))
471 (if is_utc then "UTC" else tzname)
472 (if is_utc then 0 else fromIntegral tz)
473 (if is_utc then False else isdst /= 0))
474 #endif /* ! __HUGS__ */
476 toClockTime :: CalendarTime -> ClockTime
478 toClockTime (CalendarTime yr mon mday hour min sec psec
479 _wday _yday _tzname tz _isdst) =
481 s <- toClockTimePrim (yr-1900) (fromEnum mon) mday hour min sec tz
482 return (TOD (fromIntegral s) psec)
483 #else /* ! __HUGS__ */
484 toClockTime (CalendarTime year mon mday hour min sec psec
485 _wday _yday _tzname tz isdst) =
487 -- `isDst' causes the date to be wrong by one hour...
488 -- FIXME: check, whether this works on other arch's than Linux, too...
490 -- so we set it to (-1) (means `unknown') and let `mktime' determine
492 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
494 if psec < 0 || psec > 999999999999 then
495 error "Time.toClockTime: picoseconds out of range"
496 else if tz < -43200 || tz > 43200 then
497 error "Time.toClockTime: timezone offset out of range"
500 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
501 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
502 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
503 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
504 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
505 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
506 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
507 (#poke struct tm,tm_isdst) p_tm isDst
508 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
511 -- mktime expects its argument to be in the local timezone, but
512 -- toUTCTime makes UTC-encoded CalendarTime's ...
514 -- Since there is no any_tz_struct_tm-to-time_t conversion
515 -- function, we have to fake one... :-) If not in all, it works in
516 -- most cases (before, it was the other way round...)
518 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
519 -- to compensate, we add the timezone difference to mktime's
522 gmtoff <- gmtoff p_tm
523 let res = fromIntegral t - tz + fromIntegral gmtoff
524 return (TOD (fromIntegral res) psec)
525 #endif /* ! __HUGS__ */
527 -- -----------------------------------------------------------------------------
528 -- Converting time values to strings.
530 calendarTimeToString :: CalendarTime -> String
531 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
533 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
534 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
535 wday yday tzname _ _) =
537 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
538 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
539 doFmt ('%':c:cs) = decode c ++ doFmt cs
540 doFmt (c:cs) = c : doFmt cs
543 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
544 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
545 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
546 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
547 decode 'h' = snd (months l !! fromEnum mon) -- ditto
548 decode 'C' = show2 (year `quot` 100) -- century
549 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
550 decode 'D' = doFmt "%m/%d/%y"
551 decode 'd' = show2 day -- day of the month
552 decode 'e' = show2' day -- ditto, padded
553 decode 'H' = show2 hour -- hours, 24-hour clock, padded
554 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
555 decode 'j' = show3 yday -- day of the year
556 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
557 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
558 decode 'M' = show2 min -- minutes
559 decode 'm' = show2 (fromEnum mon+1) -- numeric month
561 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
562 decode 'R' = doFmt "%H:%M"
563 decode 'r' = doFmt (time12Fmt l)
564 decode 'T' = doFmt "%H:%M:%S"
566 decode 'S' = show2 sec -- seconds
567 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
568 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
569 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
570 if n == 0 then 7 else n)
571 decode 'V' = -- week number (as per ISO-8601.)
572 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
573 (yday + 7 - if fromEnum wday > 0 then
574 fromEnum wday - 1 else 6) `divMod` 7
575 in show2 (if days >= 4 then
577 else if week == 0 then 53 else week)
579 decode 'W' = -- week number, weeks starting on monday
580 show2 ((yday + 7 - if fromEnum wday > 0 then
581 fromEnum wday - 1 else 6) `div` 7)
582 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
583 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
584 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
585 decode 'Y' = show year -- year, including century.
586 decode 'y' = show2 (year `rem` 100) -- year, within century.
587 decode 'Z' = tzname -- timezone name
592 show2, show2', show3 :: Int -> String
594 | x' < 10 = '0': show x'
595 | otherwise = show x'
596 where x' = x `rem` 100
599 | x' < 10 = ' ': show x'
600 | otherwise = show x'
601 where x' = x `rem` 100
603 show3 x = show (x `quot` 100) ++ show2 (x `rem` 100)
604 where x' = x `rem` 1000
607 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
609 -- Useful extensions for formatting TimeDiffs.
611 timeDiffToString :: TimeDiff -> String
612 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
614 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
615 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
619 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
620 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
621 doFmt ('%':c:cs) = decode c ++ doFmt cs
622 doFmt (c:cs) = c : doFmt cs
626 'B' -> fst (months l !! fromEnum month)
627 'b' -> snd (months l !! fromEnum month)
628 'h' -> snd (months l !! fromEnum month)
629 'c' -> defaultTimeDiffFmt td
630 'C' -> show2 (year `quot` 100)
631 'D' -> doFmt "%m/%d/%y"
635 'I' -> show2 (to12 hour)
637 'l' -> show2' (to12 hour)
639 'm' -> show2 (fromEnum month + 1)
641 'p' -> (if hour < 12 then fst else snd) (amPm l)
643 'r' -> doFmt (time12Fmt l)
644 'T' -> doFmt "%H:%M:%S"
647 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
648 'X' -> doFmt (timeFmt l)
649 'x' -> doFmt (dateFmt l)
651 'y' -> show2 (year `rem` 100)
655 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
656 foldr (\ (v,s) rest ->
658 then show v ++ ' ':(addS v s)
659 ++ if null rest then "" else ", "
663 (zip [year, month, day, hour, min, sec] (intervals l))
665 addS v s = if abs v == 1 then fst s else snd s
668 -- -----------------------------------------------------------------------------
669 -- Foreign time interface (POSIX)
671 type CTm = () -- struct tm
674 foreign import ccall unsafe localtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
676 foreign import ccall unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
679 foreign import ccall unsafe gmtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
681 foreign import ccall unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
683 foreign import ccall unsafe mktime :: Ptr CTm -> IO CTime
684 foreign import ccall unsafe time :: Ptr CTime -> IO CTime
686 #if HAVE_GETTIMEOFDAY
688 foreign import ccall unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
693 #ifndef mingw32_TARGET_OS
694 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO CInt
696 foreign import ccall unsafe ftime :: Ptr CTimeB -> IO ()
699 #endif /* ! __HUGS__ */