2 -- -----------------------------------------------------------------------------
3 -- $Id: Time.hsc,v 1.21 2001/09/06 15:38:16 sewardj Exp $
5 -- (c) The University of Glasgow, 1995-2001
9 Haskell 98 Time of Day Library
10 ------------------------------
12 The Time library provides standard functionality for clock times,
13 including timezone information (i.e, the functionality of "time.h",
14 adapted to the Haskell environment), It follows RFC 1129 in its use of
15 Coordinated Universal Time (UTC).
17 2000/06/17 <michael.weber@post.rwth-aachen.de>:
19 * min./max. time diff currently is restricted to
20 [minBound::Int, maxBound::Int]
22 * surely other restrictions wrt. min/max bounds
28 `showTime' (used in `instance Show ClockTime') always prints time
29 converted to the local timezone (even if it is taken from
30 `(toClockTime . toUTCTime)'), whereas `calendarTimeToString'
31 honors the tzone & tz fields and prints UTC or whatever timezone
32 is stored inside CalendarTime.
34 Maybe `showTime' should be changed to use UTC, since it would
35 better correspond to the actual representation of `ClockTime'
36 (can be done by replacing localtime(3) by gmtime(3)).
40 * add proper handling of microsecs, currently, they're mostly
43 * `formatFOO' case of `%s' is currently broken...
47 * check for unusual date cases, like 1970/1/1 00:00h, and conversions
48 between different timezone's etc.
50 * check, what needs to be in the IO monad, the current situation
51 seems to be a bit inconsistent to me
53 * check whether `isDst = -1' works as expected on other arch's
56 * add functions to parse strings to `CalendarTime' (some day...)
58 * implement padding capabilities ("%_", "%-") in `formatFOO'
60 * add rfc822 timezone (+0200 is CEST) representation ("%z") in `formatFOO'
68 , ClockTime(..) -- non-standard, lib. report gives this as abstract
70 -- instance Show (non-standard)
75 , noTimeDiff -- non-standard (but useful when constructing TimeDiff vals.)
79 , normalizeTimeDiff -- non-standard
80 , timeDiffToString -- non-standard
81 , formatTimeDiff -- non-standard
87 , calendarTimeToString
97 import PrelMarshalAlloc
98 import PrelMarshalUtils
99 import PrelMarshalError
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)))
140 showList = showList__ (showsPrec 0)
143 @CalendarTime@ is a user-readable and manipulable
144 representation of the internal $ClockTime$ type. The
145 numeric fields have the following ranges.
151 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
152 mon 0 .. 11 [Jan = 0, Dec = 11]
156 sec 0 .. 61 [Allows for two leap seconds]
157 picosec 0 .. (10^12)-1 [This could be over-precise?]
158 wday 0 .. 6 [Sunday = 0, Saturday = 6]
159 yday 0 .. 365 [364 in non-Leap years]
160 tz -43200 .. 43200 [Variation from UTC in seconds]
163 The {\em tzname} field is the name of the time zone. The {\em isdst}
164 field indicates whether Daylight Savings Time would be in effect.
175 ctPicosec :: Integer,
182 deriving (Eq,Ord,Read,Show)
184 -- The @TimeDiff@ type records the difference between two clock times in
185 -- a user-readable way.
195 tdPicosec :: Integer -- not standard
197 deriving (Eq,Ord,Read,Show)
199 noTimeDiff :: TimeDiff
200 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
202 -- -----------------------------------------------------------------------------
203 -- getClockTime returns the current time in its internal representation.
205 #if HAVE_GETTIMEOFDAY
207 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
208 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
209 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CTime
210 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CTime
211 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000))
215 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
217 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
218 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
219 return (TOD (fromIntegral sec) (fromIntegral msec * 1000{-ToDo: correct???-}))
221 #else /* use POSIX time() */
223 secs <- time nullPtr -- can't fail, according to POSIX
224 return (TOD (fromIntegral secs) 0)
228 -- -----------------------------------------------------------------------------
229 -- addToClockTime d t adds a time difference d and a
230 -- clock time t to yield a new clock time. The difference d
231 -- may be either positive or negative. diffClockTimes t1 t2 returns
232 -- the difference between two clock times t1 and t2 as a TimeDiff.
234 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
235 addToClockTime (TimeDiff year mon day hour min sec psec)
238 sec_diff = toInteger sec +
240 3600 * toInteger hour +
241 24 * 3600 * toInteger day
242 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
244 new_mon = fromEnum (ctMonth cal) + r_mon
246 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
247 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
248 | otherwise = (toEnum new_mon, 0)
250 (r_yr, r_mon) = mon `quotRem` 12
252 year' = ctYear cal + year + r_yr + yr_diff
254 toClockTime cal{ctMonth=month', ctYear=year'}
256 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
257 -- diffClockTimes is meant to be the dual to `addToClockTime'.
258 -- If you want to have the TimeDiff properly splitted, use
259 -- `normalizeTimeDiff' on this function's result
261 -- CAVEAT: see comment of normalizeTimeDiff
262 diffClockTimes (TOD sa pa) (TOD sb pb) =
263 noTimeDiff{ tdSec = fromIntegral (sa - sb)
264 -- FIXME: can handle just 68 years...
265 , tdPicosec = pa - pb
269 normalizeTimeDiff :: TimeDiff -> TimeDiff
270 -- FIXME: handle psecs properly
271 -- FIXME: ?should be called by formatTimeDiff automagically?
273 -- when applied to something coming out of `diffClockTimes', you loose
274 -- the duality to `addToClockTime', since a year does not always have
277 -- apply this function as late as possible to prevent those "rounding"
279 normalizeTimeDiff td =
286 + 365 * tdYear td))))
288 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
289 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
290 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
291 (diffHours, rest4) = rest3 `quotRem` 3600
292 (diffMins, diffSecs) = rest4 `quotRem` 60
294 td{ tdYear = diffYears
295 , tdMonth = diffMonths
302 -- -----------------------------------------------------------------------------
303 -- How do we deal with timezones on this architecture?
305 -- The POSIX way to do it is through the global variable tzname[].
306 -- But that's crap, so we do it The BSD Way if we can: namely use the
307 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
309 zone :: Ptr CTm -> IO (Ptr CChar)
310 gmtoff :: Ptr CTm -> IO CLong
312 zone x = (#peek struct tm,tm_zone) x
313 gmtoff x = (#peek struct tm,tm_gmtoff) x
315 #else /* ! HAVE_TM_ZONE */
316 # if HAVE_TZNAME || defined(_WIN32)
317 # if cygwin32_TARGET_OS
318 # define tzname _tzname
320 # ifndef mingw32_TARGET_OS
321 foreign label tzname :: Ptr (Ptr CChar)
323 foreign import "ghcTimezone" unsafe timezone :: Ptr CLong
324 foreign import "ghcTzname" unsafe tzname :: Ptr (Ptr CChar)
325 # def inline long *ghcTimezone(void) { return &_timezone; }
326 # def inline char **ghcTzname(void) { return _tzname; }
329 dst <- (#peek struct tm,tm_isdst) x
330 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
331 # else /* ! HAVE_TZNAME */
332 -- We're in trouble. If you should end up here, please report this as a bug.
333 # error "Don't know how to get at timezone name on your OS."
334 # endif /* ! HAVE_TZNAME */
336 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
337 #if defined(mingw32_TARGET_OS) || defined(cygwin32_TARGET_OS)
338 #define timezone _timezone
342 foreign label altzone :: Ptr CTime
343 foreign label timezone :: Ptr CTime
345 dst <- (#peek struct tm,tm_isdst) x
346 tz <- if dst then peek altzone else peek timezone
347 return (fromIntegral tz)
348 # define GMTOFF(x) (((struct tm *)x)->tm_isdst ? altzone : timezone )
349 # else /* ! HAVE_ALTZONE */
350 -- Assume that DST offset is 1 hour ...
352 dst <- (#peek struct tm,tm_isdst) x
354 if dst then return (fromIntegral tz - 3600) else return tz
355 # endif /* ! HAVE_ALTZONE */
356 #endif /* ! HAVE_TM_ZONE */
358 -- -----------------------------------------------------------------------------
359 -- toCalendarTime t converts t to a local time, modified by
360 -- the current timezone and daylight savings time settings. toUTCTime
361 -- t converts t into UTC time. toClockTime l converts l into the
362 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
366 toCalendarTime :: ClockTime -> IO CalendarTime
368 toCalendarTime = clockToCalendarTime_reentrant (throwAwayReturnPointer localtime_r) False
370 toCalendarTime = clockToCalendarTime_static localtime False
373 toUTCTime :: ClockTime -> CalendarTime
375 toUTCTime = unsafePerformIO . clockToCalendarTime_reentrant (throwAwayReturnPointer gmtime_r) True
377 toUTCTime = unsafePerformIO . clockToCalendarTime_static gmtime True
380 throwAwayReturnPointer :: (Ptr CTime -> Ptr CTm -> IO (Ptr CTm))
381 -> (Ptr CTime -> Ptr CTm -> IO ( ))
382 throwAwayReturnPointer fun x y = fun x y >> return ()
384 clockToCalendarTime_static :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
386 clockToCalendarTime_static fun is_utc (TOD secs psec) = do
387 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
388 p_tm <- fun p_timer -- can't fail, according to POSIX
389 clockToCalendarTime_aux is_utc p_tm psec
391 clockToCalendarTime_reentrant :: (Ptr CTime -> Ptr CTm -> IO ()) -> Bool -> ClockTime
393 clockToCalendarTime_reentrant fun is_utc (TOD secs psec) = do
394 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
395 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
397 clockToCalendarTime_aux is_utc p_tm psec
399 clockToCalendarTime_aux :: Bool -> Ptr CTm -> Integer -> IO CalendarTime
400 clockToCalendarTime_aux is_utc p_tm psec = do
401 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
402 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
403 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
404 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
405 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
406 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
407 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
408 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
409 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
413 tzname <- peekCString zone
415 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
416 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
419 (1900 + fromIntegral year)
426 (toEnum (fromIntegral wday))
428 (if is_utc then "UTC" else tzname)
429 (if is_utc then 0 else fromIntegral tz)
430 (if is_utc then False else isdst /= 0))
433 toClockTime :: CalendarTime -> ClockTime
434 toClockTime (CalendarTime year mon mday hour min sec psec
435 _wday _yday _tzname tz isdst) =
437 -- `isDst' causes the date to be wrong by one hour...
438 -- FIXME: check, whether this works on other arch's than Linux, too...
440 -- so we set it to (-1) (means `unknown') and let `mktime' determine
442 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
444 if psec < 0 || psec > 999999999999 then
445 error "Time.toClockTime: picoseconds out of range"
446 else if tz < -43200 || tz > 43200 then
447 error "Time.toClockTime: timezone offset out of range"
450 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
451 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
452 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
453 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
454 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
455 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
456 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
457 (#poke struct tm,tm_isdst) p_tm isDst
458 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
461 -- mktime expects its argument to be in the local timezone, but
462 -- toUTCTime makes UTC-encoded CalendarTime's ...
464 -- Since there is no any_tz_struct_tm-to-time_t conversion
465 -- function, we have to fake one... :-) If not in all, it works in
466 -- most cases (before, it was the other way round...)
468 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
469 -- to compensate, we add the timezone difference to mktime's
472 gmtoff <- gmtoff p_tm
473 let res = fromIntegral t - tz + fromIntegral gmtoff
474 return (TOD (fromIntegral res) 0)
476 -- -----------------------------------------------------------------------------
477 -- Converting time values to strings.
479 calendarTimeToString :: CalendarTime -> String
480 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
482 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
483 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
484 wday yday tzname _ _) =
486 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
487 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
488 doFmt ('%':c:cs) = decode c ++ doFmt cs
489 doFmt (c:cs) = c : doFmt cs
492 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
493 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
494 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
495 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
496 decode 'h' = snd (months l !! fromEnum mon) -- ditto
497 decode 'C' = show2 (year `quot` 100) -- century
498 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
499 decode 'D' = doFmt "%m/%d/%y"
500 decode 'd' = show2 day -- day of the month
501 decode 'e' = show2' day -- ditto, padded
502 decode 'H' = show2 hour -- hours, 24-hour clock, padded
503 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
504 decode 'j' = show3 yday -- day of the year
505 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
506 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
507 decode 'M' = show2 min -- minutes
508 decode 'm' = show2 (fromEnum mon+1) -- numeric month
510 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
511 decode 'R' = doFmt "%H:%M"
512 decode 'r' = doFmt (time12Fmt l)
513 decode 'T' = doFmt "%H:%M:%S"
515 decode 'S' = show2 sec -- seconds
516 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
517 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
518 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
519 if n == 0 then 7 else n)
520 decode 'V' = -- week number (as per ISO-8601.)
521 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
522 (yday + 7 - if fromEnum wday > 0 then
523 fromEnum wday - 1 else 6) `divMod` 7
524 in show2 (if days >= 4 then
526 else if week == 0 then 53 else week)
528 decode 'W' = -- week number, weeks starting on monday
529 show2 ((yday + 7 - if fromEnum wday > 0 then
530 fromEnum wday - 1 else 6) `div` 7)
531 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
532 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
533 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
534 decode 'Y' = show year -- year, including century.
535 decode 'y' = show2 (year `rem` 100) -- year, within century.
536 decode 'Z' = tzname -- timezone name
541 show2, show2', show3 :: Int -> String
542 show2 x = [intToDigit (x `quot` 10), intToDigit (x `rem` 10)]
544 show2' x = if x < 10 then [ ' ', intToDigit x] else show2 x
546 show3 x = intToDigit (x `quot` 100) : show2 (x `rem` 100)
549 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
551 -- Useful extensions for formatting TimeDiffs.
553 timeDiffToString :: TimeDiff -> String
554 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
556 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
557 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
561 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
562 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
563 doFmt ('%':c:cs) = decode c ++ doFmt cs
564 doFmt (c:cs) = c : doFmt cs
568 'B' -> fst (months l !! fromEnum month)
569 'b' -> snd (months l !! fromEnum month)
570 'h' -> snd (months l !! fromEnum month)
571 'c' -> defaultTimeDiffFmt td
572 'C' -> show2 (year `quot` 100)
573 'D' -> doFmt "%m/%d/%y"
577 'I' -> show2 (to12 hour)
579 'l' -> show2' (to12 hour)
581 'm' -> show2 (fromEnum month + 1)
583 'p' -> (if hour < 12 then fst else snd) (amPm l)
585 'r' -> doFmt (time12Fmt l)
586 'T' -> doFmt "%H:%M:%S"
589 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
590 'X' -> doFmt (timeFmt l)
591 'x' -> doFmt (dateFmt l)
593 'y' -> show2 (year `rem` 100)
597 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
598 foldr (\ (v,s) rest ->
600 then show v ++ ' ':(addS v s)
601 ++ if null rest then "" else ", "
605 (zip [year, month, day, hour, min, sec] (intervals l))
607 addS v s = if abs v == 1 then fst s else snd s
610 -- -----------------------------------------------------------------------------
611 -- Foreign time interface (POSIX)
613 type CTm = () -- struct tm
616 foreign import unsafe localtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
618 foreign import unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
621 foreign import unsafe gmtime_r :: Ptr CTime -> Ptr CTm -> IO (Ptr CTm)
623 foreign import unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
625 foreign import unsafe mktime :: Ptr CTm -> IO CTime
626 foreign import unsafe time :: Ptr CTime -> IO CTime
628 #if HAVE_GETTIMEOFDAY
630 foreign import unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
635 #ifndef mingw32_TARGET_OS
636 foreign import unsafe ftime :: Ptr CTimeB -> IO CInt
638 foreign import unsafe ftime :: Ptr CTimeB -> IO ()