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 -- $Id: Time.hsc,v 1.6 2001/12/21 15:07:26 simonmar Exp $
13 -- The standard Time library.
15 -----------------------------------------------------------------------------
18 Haskell 98 Time of Day Library
19 ------------------------------
21 The Time library provides standard functionality for clock times,
22 including timezone information (i.e, the functionality of "time.h",
23 adapted to the Haskell environment), It follows RFC 1129 in its use of
24 Coordinated Universal Time (UTC).
26 2000/06/17 <michael.weber@post.rwth-aachen.de>:
28 * min./max. time diff currently is restricted to
29 [minBound::Int, maxBound::Int]
31 * surely other restrictions wrt. min/max bounds
37 `showTime' (used in `instance Show ClockTime') always prints time
38 converted to the local timezone (even if it is taken from
39 `(toClockTime . toUTCTime)'), whereas `calendarTimeToString'
40 honors the tzone & tz fields and prints UTC or whatever timezone
41 is stored inside CalendarTime.
43 Maybe `showTime' should be changed to use UTC, since it would
44 better correspond to the actual representation of `ClockTime'
45 (can be done by replacing localtime(3) by gmtime(3)).
49 * add proper handling of microsecs, currently, they're mostly
52 * `formatFOO' case of `%s' is currently broken...
56 * check for unusual date cases, like 1970/1/1 00:00h, and conversions
57 between different timezone's etc.
59 * check, what needs to be in the IO monad, the current situation
60 seems to be a bit inconsistent to me
62 * check whether `isDst = -1' works as expected on other arch's
65 * add functions to parse strings to `CalendarTime' (some day...)
67 * implement padding capabilities ("%_", "%-") in `formatFOO'
69 * add rfc822 timezone (+0200 is CEST) representation ("%z") in `formatFOO'
77 , ClockTime(..) -- non-standard, lib. report gives this as abstract
79 -- instance Show (non-standard)
84 , noTimeDiff -- non-standard (but useful when constructing TimeDiff vals.)
88 , normalizeTimeDiff -- non-standard
89 , timeDiffToString -- non-standard
90 , formatTimeDiff -- non-standard
96 , calendarTimeToString
107 import System.IO.Unsafe
112 -- One way to partition and give name to chunks of a year and a week:
115 = January | February | March | April
116 | May | June | July | August
117 | September | October | November | December
118 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
121 = Sunday | Monday | Tuesday | Wednesday
122 | Thursday | Friday | Saturday
123 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
125 -- @ClockTime@ is an abstract type, used for the internal clock time.
126 -- Clock times may be compared, converted to strings, or converted to an
127 -- external calendar time @CalendarTime@.
129 data ClockTime = TOD Integer -- Seconds since 00:00:00 on 1 Jan 1970
130 Integer -- Picoseconds with the specified second
133 -- When a ClockTime is shown, it is converted to a CalendarTime in the current
134 -- timezone and then printed. FIXME: This is arguably wrong, since we can't
135 -- get the current timezone without being in the IO monad.
137 instance Show ClockTime where
138 showsPrec _ t = showString (calendarTimeToString
139 (unsafePerformIO (toCalendarTime t)))
142 @CalendarTime@ is a user-readable and manipulable
143 representation of the internal $ClockTime$ type. The
144 numeric fields have the following ranges.
150 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
151 mon 0 .. 11 [Jan = 0, Dec = 11]
155 sec 0 .. 61 [Allows for two leap seconds]
156 picosec 0 .. (10^12)-1 [This could be over-precise?]
157 wday 0 .. 6 [Sunday = 0, Saturday = 6]
158 yday 0 .. 365 [364 in non-Leap years]
159 tz -43200 .. 43200 [Variation from UTC in seconds]
162 The {\em tzname} field is the name of the time zone. The {\em isdst}
163 field indicates whether Daylight Savings Time would be in effect.
174 ctPicosec :: Integer,
181 deriving (Eq,Ord,Read,Show)
183 -- The @TimeDiff@ type records the difference between two clock times in
184 -- a user-readable way.
194 tdPicosec :: Integer -- not standard
196 deriving (Eq,Ord,Read,Show)
198 noTimeDiff :: TimeDiff
199 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
201 -- -----------------------------------------------------------------------------
202 -- getClockTime returns the current time in its internal representation.
204 #if HAVE_GETTIMEOFDAY
206 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
207 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
208 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CTime
209 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CTime
210 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000000))
214 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
216 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
217 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
218 return (TOD (fromIntegral sec) (fromIntegral msec * 1000000000))
220 #else /* use POSIX time() */
222 secs <- time nullPtr -- can't fail, according to POSIX
223 return (TOD (fromIntegral secs) 0)
227 -- -----------------------------------------------------------------------------
228 -- addToClockTime d t adds a time difference d and a
229 -- clock time t to yield a new clock time. The difference d
230 -- may be either positive or negative. diffClockTimes t1 t2 returns
231 -- the difference between two clock times t1 and t2 as a TimeDiff.
233 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
234 addToClockTime (TimeDiff year mon day hour min sec psec)
237 sec_diff = toInteger sec +
239 3600 * toInteger hour +
240 24 * 3600 * toInteger day
241 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
243 new_mon = fromEnum (ctMonth cal) + r_mon
245 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
246 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
247 | otherwise = (toEnum new_mon, 0)
249 (r_yr, r_mon) = mon `quotRem` 12
251 year' = ctYear cal + year + r_yr + yr_diff
253 toClockTime cal{ctMonth=month', ctYear=year'}
255 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
256 -- diffClockTimes is meant to be the dual to `addToClockTime'.
257 -- If you want to have the TimeDiff properly splitted, use
258 -- `normalizeTimeDiff' on this function's result
260 -- CAVEAT: see comment of normalizeTimeDiff
261 diffClockTimes (TOD sa pa) (TOD sb pb) =
262 noTimeDiff{ tdSec = fromIntegral (sa - sb)
263 -- FIXME: can handle just 68 years...
264 , tdPicosec = pa - pb
268 normalizeTimeDiff :: TimeDiff -> TimeDiff
269 -- FIXME: handle psecs properly
270 -- FIXME: ?should be called by formatTimeDiff automagically?
272 -- when applied to something coming out of `diffClockTimes', you loose
273 -- the duality to `addToClockTime', since a year does not always have
276 -- apply this function as late as possible to prevent those "rounding"
278 normalizeTimeDiff td =
285 + 365 * tdYear td))))
287 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
288 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
289 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
290 (diffHours, rest4) = rest3 `quotRem` 3600
291 (diffMins, diffSecs) = rest4 `quotRem` 60
293 td{ tdYear = diffYears
294 , tdMonth = diffMonths
301 -- -----------------------------------------------------------------------------
302 -- How do we deal with timezones on this architecture?
304 -- The POSIX way to do it is through the global variable tzname[].
305 -- But that's crap, so we do it The BSD Way if we can: namely use the
306 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
308 zone :: Ptr CTm -> IO (Ptr CChar)
309 gmtoff :: Ptr CTm -> IO CLong
311 zone x = (#peek struct tm,tm_zone) x
312 gmtoff x = (#peek struct tm,tm_gmtoff) x
314 #else /* ! HAVE_TM_ZONE */
315 # if HAVE_TZNAME || defined(_WIN32)
316 # if cygwin32_TARGET_OS
317 # define tzname _tzname
319 # ifndef mingw32_TARGET_OS
320 foreign label tzname :: Ptr (Ptr CChar)
322 foreign import "ghcTimezone" unsafe timezone :: Ptr CLong
323 foreign import "ghcTzname" unsafe tzname :: Ptr (Ptr CChar)
324 # def inline long *ghcTimezone(void) { return &_timezone; }
325 # def inline char **ghcTzname(void) { return _tzname; }
328 dst <- (#peek struct tm,tm_isdst) x
329 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
330 # else /* ! HAVE_TZNAME */
331 -- We're in trouble. If you should end up here, please report this as a bug.
332 # error "Don't know how to get at timezone name on your OS."
333 # endif /* ! HAVE_TZNAME */
335 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
336 #if defined(mingw32_TARGET_OS) || defined(cygwin32_TARGET_OS)
337 #define timezone _timezone
341 foreign label altzone :: Ptr CTime
342 foreign label timezone :: Ptr CTime
344 dst <- (#peek struct tm,tm_isdst) x
345 tz <- if dst then peek altzone else peek timezone
346 return (fromIntegral tz)
347 # define GMTOFF(x) (((struct tm *)x)->tm_isdst ? altzone : timezone )
348 # else /* ! HAVE_ALTZONE */
349 -- Assume that DST offset is 1 hour ...
351 dst <- (#peek struct tm,tm_isdst) x
353 if dst then return (fromIntegral tz - 3600) else return tz
354 # endif /* ! HAVE_ALTZONE */
355 #endif /* ! HAVE_TM_ZONE */
357 -- -----------------------------------------------------------------------------
358 -- toCalendarTime t converts t to a local time, modified by
359 -- the current timezone and daylight savings time settings. toUTCTime
360 -- t converts t into UTC time. toClockTime l converts l into the
361 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
365 toCalendarTime :: ClockTime -> IO CalendarTime
367 toCalendarTime = clockToCalendarTime_reentrant (throwAwayReturnPointer localtime_r) False
369 toCalendarTime = clockToCalendarTime_static localtime False
372 toUTCTime :: ClockTime -> CalendarTime
374 toUTCTime = unsafePerformIO . clockToCalendarTime_reentrant (throwAwayReturnPointer gmtime_r) True
376 toUTCTime = unsafePerformIO . clockToCalendarTime_static gmtime True
379 throwAwayReturnPointer :: (Ptr CTime -> Ptr CTm -> IO (Ptr CTm))
380 -> (Ptr CTime -> Ptr CTm -> IO ( ))
381 throwAwayReturnPointer fun x y = fun x y >> return ()
383 clockToCalendarTime_static :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
385 clockToCalendarTime_static fun is_utc (TOD secs psec) = do
386 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
387 p_tm <- fun p_timer -- can't fail, according to POSIX
388 clockToCalendarTime_aux is_utc p_tm psec
390 clockToCalendarTime_reentrant :: (Ptr CTime -> Ptr CTm -> IO ()) -> Bool -> ClockTime
392 clockToCalendarTime_reentrant fun is_utc (TOD secs psec) = do
393 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
394 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
396 clockToCalendarTime_aux is_utc p_tm psec
398 clockToCalendarTime_aux :: Bool -> Ptr CTm -> Integer -> IO CalendarTime
399 clockToCalendarTime_aux is_utc p_tm psec = do
400 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
401 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
402 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
403 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
404 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
405 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
406 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
407 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
408 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
412 tzname <- peekCString zone
414 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
415 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
418 (1900 + fromIntegral year)
425 (toEnum (fromIntegral wday))
427 (if is_utc then "UTC" else tzname)
428 (if is_utc then 0 else fromIntegral tz)
429 (if is_utc then False else isdst /= 0))
432 toClockTime :: CalendarTime -> ClockTime
433 toClockTime (CalendarTime year mon mday hour min sec psec
434 _wday _yday _tzname tz isdst) =
436 -- `isDst' causes the date to be wrong by one hour...
437 -- FIXME: check, whether this works on other arch's than Linux, too...
439 -- so we set it to (-1) (means `unknown') and let `mktime' determine
441 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
443 if psec < 0 || psec > 999999999999 then
444 error "Time.toClockTime: picoseconds out of range"
445 else if tz < -43200 || tz > 43200 then
446 error "Time.toClockTime: timezone offset out of range"
449 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
450 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
451 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
452 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
453 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
454 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
455 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
456 (#poke struct tm,tm_isdst) p_tm isDst
457 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
460 -- mktime expects its argument to be in the local timezone, but
461 -- toUTCTime makes UTC-encoded CalendarTime's ...
463 -- Since there is no any_tz_struct_tm-to-time_t conversion
464 -- function, we have to fake one... :-) If not in all, it works in
465 -- most cases (before, it was the other way round...)
467 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
468 -- to compensate, we add the timezone difference to mktime's
471 gmtoff <- gmtoff p_tm
472 let res = fromIntegral t - tz + fromIntegral gmtoff
473 return (TOD (fromIntegral res) psec)
475 -- -----------------------------------------------------------------------------
476 -- Converting time values to strings.
478 calendarTimeToString :: CalendarTime -> String
479 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
481 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
482 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
483 wday yday tzname _ _) =
485 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
486 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
487 doFmt ('%':c:cs) = decode c ++ doFmt cs
488 doFmt (c:cs) = c : doFmt cs
491 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
492 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
493 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
494 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
495 decode 'h' = snd (months l !! fromEnum mon) -- ditto
496 decode 'C' = show2 (year `quot` 100) -- century
497 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
498 decode 'D' = doFmt "%m/%d/%y"
499 decode 'd' = show2 day -- day of the month
500 decode 'e' = show2' day -- ditto, padded
501 decode 'H' = show2 hour -- hours, 24-hour clock, padded
502 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
503 decode 'j' = show3 yday -- day of the year
504 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
505 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
506 decode 'M' = show2 min -- minutes
507 decode 'm' = show2 (fromEnum mon+1) -- numeric month
509 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
510 decode 'R' = doFmt "%H:%M"
511 decode 'r' = doFmt (time12Fmt l)
512 decode 'T' = doFmt "%H:%M:%S"
514 decode 'S' = show2 sec -- seconds
515 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
516 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
517 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
518 if n == 0 then 7 else n)
519 decode 'V' = -- week number (as per ISO-8601.)
520 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
521 (yday + 7 - if fromEnum wday > 0 then
522 fromEnum wday - 1 else 6) `divMod` 7
523 in show2 (if days >= 4 then
525 else if week == 0 then 53 else week)
527 decode 'W' = -- week number, weeks starting on monday
528 show2 ((yday + 7 - if fromEnum wday > 0 then
529 fromEnum wday - 1 else 6) `div` 7)
530 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
531 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
532 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
533 decode 'Y' = show year -- year, including century.
534 decode 'y' = show2 (year `rem` 100) -- year, within century.
535 decode 'Z' = tzname -- timezone name
540 show2, show2', show3 :: Int -> String
542 | x' < 10 = '0': show x'
543 | otherwise = show x'
544 where x' = x `rem` 100
547 | x' < 10 = ' ': show x'
548 | otherwise = show x'
549 where x' = x `rem` 100
551 show3 x = show (x `quot` 100) ++ show2 (x `rem` 100)
552 where x' = x `rem` 1000
555 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
557 -- Useful extensions for formatting TimeDiffs.
559 timeDiffToString :: TimeDiff -> String
560 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
562 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
563 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
567 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
568 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
569 doFmt ('%':c:cs) = decode c ++ doFmt cs
570 doFmt (c:cs) = c : doFmt cs
574 'B' -> fst (months l !! fromEnum month)
575 'b' -> snd (months l !! fromEnum month)
576 'h' -> snd (months l !! fromEnum month)
577 'c' -> defaultTimeDiffFmt td
578 'C' -> show2 (year `quot` 100)
579 'D' -> doFmt "%m/%d/%y"
583 'I' -> show2 (to12 hour)
585 'l' -> show2' (to12 hour)
587 'm' -> show2 (fromEnum month + 1)
589 'p' -> (if hour < 12 then fst else snd) (amPm l)
591 'r' -> doFmt (time12Fmt l)
592 'T' -> doFmt "%H:%M:%S"
595 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
596 'X' -> doFmt (timeFmt l)
597 'x' -> doFmt (dateFmt l)
599 'y' -> show2 (year `rem` 100)
603 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
604 foldr (\ (v,s) rest ->
606 then show v ++ ' ':(addS v s)
607 ++ if null rest then "" else ", "
611 (zip [year, month, day, hour, min, sec] (intervals l))
613 addS v s = if abs v == 1 then fst s else snd s
616 -- -----------------------------------------------------------------------------
617 -- Foreign time interface (POSIX)
619 type CTm = () -- struct tm
622 foreign import unsafe localtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
624 foreign import unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
627 foreign import unsafe gmtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
629 foreign import unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
631 foreign import unsafe mktime :: Ptr CTm -> IO CTime
632 foreign import unsafe time :: Ptr CTime -> IO CTime
634 #if HAVE_GETTIMEOFDAY
636 foreign import unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
641 #ifndef mingw32_TARGET_OS
642 foreign import unsafe ftime :: Ptr CTimeB -> IO CInt
644 foreign import unsafe ftime :: Ptr CTimeB -> IO ()