1 {-# OPTIONS -optc-DNON_POSIX_SOURCE #-}
2 -- JRS 010117: we had to say NON_POSIX_SOURCE to get the resulting .hc
3 -- to compile on sparc-solaris. Blargh.
4 -----------------------------------------------------------------------------
6 -- Module : System.Time
7 -- Copyright : (c) The University of Glasgow 2001
8 -- License : BSD-style (see the file libraries/core/LICENSE)
10 -- Maintainer : libraries@haskell.org
11 -- Stability : provisional
12 -- Portability : portable
14 -- $Id: Time.hsc,v 1.1 2001/06/28 14:15:04 simonmar Exp $
16 -- The standard Time library.
18 -----------------------------------------------------------------------------
21 Haskell 98 Time of Day Library
22 ------------------------------
24 The Time library provides standard functionality for clock times,
25 including timezone information (i.e, the functionality of "time.h",
26 adapted to the Haskell environment), It follows RFC 1129 in its use of
27 Coordinated Universal Time (UTC).
29 2000/06/17 <michael.weber@post.rwth-aachen.de>:
31 * min./max. time diff currently is restricted to
32 [minBound::Int, maxBound::Int]
34 * surely other restrictions wrt. min/max bounds
40 `showTime' (used in `instance Show ClockTime') always prints time
41 converted to the local timezone (even if it is taken from
42 `(toClockTime . toUTCTime)'), whereas `calendarTimeToString'
43 honors the tzone & tz fields and prints UTC or whatever timezone
44 is stored inside CalendarTime.
46 Maybe `showTime' should be changed to use UTC, since it would
47 better correspond to the actual representation of `ClockTime'
48 (can be done by replacing localtime(3) by gmtime(3)).
52 * add proper handling of microsecs, currently, they're mostly
55 * `formatFOO' case of `%s' is currently broken...
59 * check for unusual date cases, like 1970/1/1 00:00h, and conversions
60 between different timezone's etc.
62 * check, what needs to be in the IO monad, the current situation
63 seems to be a bit inconsistent to me
65 * check whether `isDst = -1' works as expected on other arch's
68 * add functions to parse strings to `CalendarTime' (some day...)
70 * implement padding capabilities ("%_", "%-") in `formatFOO'
72 * add rfc822 timezone (+0200 is CEST) representation ("%z") in `formatFOO'
80 , ClockTime(..) -- non-standard, lib. report gives this as abstract
82 -- instance Show (non-standard)
87 , noTimeDiff -- non-standard (but useful when constructing TimeDiff vals.)
91 , normalizeTimeDiff -- non-standard
92 , timeDiffToString -- non-standard
93 , formatTimeDiff -- non-standard
99 , calendarTimeToString
110 import System.IO.Unsafe
115 -- One way to partition and give name to chunks of a year and a week:
118 = January | February | March | April
119 | May | June | July | August
120 | September | October | November | December
121 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
124 = Sunday | Monday | Tuesday | Wednesday
125 | Thursday | Friday | Saturday
126 deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
128 -- @ClockTime@ is an abstract type, used for the internal clock time.
129 -- Clock times may be compared, converted to strings, or converted to an
130 -- external calendar time @CalendarTime@.
132 data ClockTime = TOD Integer -- Seconds since 00:00:00 on 1 Jan 1970
133 Integer -- Picoseconds with the specified second
136 -- When a ClockTime is shown, it is converted to a CalendarTime in the current
137 -- timezone and then printed. FIXME: This is arguably wrong, since we can't
138 -- get the current timezone without being in the IO monad.
140 instance Show ClockTime where
141 showsPrec _ t = showString (calendarTimeToString
142 (unsafePerformIO (toCalendarTime t)))
145 @CalendarTime@ is a user-readable and manipulable
146 representation of the internal $ClockTime$ type. The
147 numeric fields have the following ranges.
153 year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
154 mon 0 .. 11 [Jan = 0, Dec = 11]
158 sec 0 .. 61 [Allows for two leap seconds]
159 picosec 0 .. (10^12)-1 [This could be over-precise?]
160 wday 0 .. 6 [Sunday = 0, Saturday = 6]
161 yday 0 .. 365 [364 in non-Leap years]
162 tz -43200 .. 43200 [Variation from UTC in seconds]
165 The {\em tzname} field is the name of the time zone. The {\em isdst}
166 field indicates whether Daylight Savings Time would be in effect.
177 ctPicosec :: Integer,
184 deriving (Eq,Ord,Read,Show)
186 -- The @TimeDiff@ type records the difference between two clock times in
187 -- a user-readable way.
197 tdPicosec :: Integer -- not standard
199 deriving (Eq,Ord,Read,Show)
201 noTimeDiff :: TimeDiff
202 noTimeDiff = TimeDiff 0 0 0 0 0 0 0
204 -- -----------------------------------------------------------------------------
205 -- getClockTime returns the current time in its internal representation.
207 #if HAVE_GETTIMEOFDAY
209 allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
210 throwErrnoIfMinus1_ "getClockTime" $ gettimeofday p_timeval nullPtr
211 sec <- (#peek struct timeval,tv_sec) p_timeval :: IO CLong
212 usec <- (#peek struct timeval,tv_usec) p_timeval :: IO CLong
213 return (TOD (fromIntegral sec) ((fromIntegral usec) * 1000))
217 allocaBytes (#const sizeof(struct timeb)) $ \ p_timeb -> do
219 sec <- (#peek struct timeb,time) p_timeb :: IO CTime
220 msec <- (#peek struct timeb,millitm) p_timeb :: IO CUShort
221 return (TOD (fromIntegral sec) (fromIntegral msec * 1000{-ToDo: correct???-}))
223 #else /* use POSIX time() */
225 secs <- time nullPtr -- can't fail, according to POSIX
226 return (TOD (fromIntegral secs) 0)
230 -- -----------------------------------------------------------------------------
231 -- addToClockTime d t adds a time difference d and a
232 -- clock time t to yield a new clock time. The difference d
233 -- may be either positive or negative. diffClockTimes t1 t2 returns
234 -- the difference between two clock times t1 and t2 as a TimeDiff.
236 addToClockTime :: TimeDiff -> ClockTime -> ClockTime
237 addToClockTime (TimeDiff year mon day hour min sec psec)
240 sec_diff = toInteger sec +
242 3600 * toInteger hour +
243 24 * 3600 * toInteger day
244 cal = toUTCTime (TOD (c_sec + sec_diff) (c_psec + psec))
246 new_mon = fromEnum (ctMonth cal) + r_mon
248 | new_mon < 0 = (toEnum (12 + new_mon), (-1))
249 | new_mon > 11 = (toEnum (new_mon `mod` 12), 1)
250 | otherwise = (toEnum new_mon, 0)
252 (r_yr, r_mon) = mon `quotRem` 12
254 year' = ctYear cal + year + r_yr + yr_diff
256 toClockTime cal{ctMonth=month', ctYear=year'}
258 diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
259 -- diffClockTimes is meant to be the dual to `addToClockTime'.
260 -- If you want to have the TimeDiff properly splitted, use
261 -- `normalizeTimeDiff' on this function's result
263 -- CAVEAT: see comment of normalizeTimeDiff
264 diffClockTimes (TOD sa pa) (TOD sb pb) =
265 noTimeDiff{ tdSec = fromIntegral (sa - sb)
266 -- FIXME: can handle just 68 years...
267 , tdPicosec = pa - pb
271 normalizeTimeDiff :: TimeDiff -> TimeDiff
272 -- FIXME: handle psecs properly
273 -- FIXME: ?should be called by formatTimeDiff automagically?
275 -- when applied to something coming out of `diffClockTimes', you loose
276 -- the duality to `addToClockTime', since a year does not always have
279 -- apply this function as late as possible to prevent those "rounding"
281 normalizeTimeDiff td =
288 + 365 * tdYear td))))
290 (diffYears, rest1) = rest0 `quotRem` (365 * 24 * 3600)
291 (diffMonths, rest2) = rest1 `quotRem` (30 * 24 * 3600)
292 (diffDays, rest3) = rest2 `quotRem` (24 * 3600)
293 (diffHours, rest4) = rest3 `quotRem` 3600
294 (diffMins, diffSecs) = rest4 `quotRem` 60
296 td{ tdYear = diffYears
297 , tdMonth = diffMonths
304 -- -----------------------------------------------------------------------------
305 -- How do we deal with timezones on this architecture?
307 -- The POSIX way to do it is through the global variable tzname[].
308 -- But that's crap, so we do it The BSD Way if we can: namely use the
309 -- tm_zone and tm_gmtoff fields of struct tm, if they're available.
311 zone :: Ptr CTm -> IO (Ptr CChar)
312 gmtoff :: Ptr CTm -> IO CLong
314 zone x = (#peek struct tm,tm_zone) x
315 gmtoff x = (#peek struct tm,tm_gmtoff) x
317 #else /* ! HAVE_TM_ZONE */
318 # if HAVE_TZNAME || defined(_WIN32)
319 # if cygwin32_TARGET_OS
320 # define tzname _tzname
322 # ifndef mingw32_TARGET_OS
323 foreign label tzname :: Ptr (Ptr CChar)
325 foreign import "ghcTimezone" unsafe timezone :: Ptr CLong
326 foreign import "ghcTzname" unsafe tzname :: Ptr (Ptr CChar)
327 # def inline long *ghcTimezone(void) { return &_timezone; }
328 # def inline char **ghcTzname(void) { return _tzname; }
331 dst <- (#peek struct tm,tm_isdst) x
332 if dst then peekElemOff tzname 1 else peekElemOff tzname 0
333 # else /* ! HAVE_TZNAME */
334 -- We're in trouble. If you should end up here, please report this as a bug.
335 # error "Don't know how to get at timezone name on your OS."
336 # endif /* ! HAVE_TZNAME */
338 -- Get the offset in secs from UTC, if (struct tm) doesn't supply it. */
339 #if defined(mingw32_TARGET_OS) || defined(cygwin32_TARGET_OS)
340 #define timezone _timezone
344 foreign label altzone :: Ptr CTime
345 foreign label timezone :: Ptr CTime
347 dst <- (#peek struct tm,tm_isdst) x
348 tz <- if dst then peek altzone else peek timezone
349 return (fromIntegral tz)
350 # define GMTOFF(x) (((struct tm *)x)->tm_isdst ? altzone : timezone )
351 # else /* ! HAVE_ALTZONE */
352 -- Assume that DST offset is 1 hour ...
354 dst <- (#peek struct tm,tm_isdst) x
356 if dst then return (fromIntegral tz - 3600) else return tz
357 # endif /* ! HAVE_ALTZONE */
358 #endif /* ! HAVE_TM_ZONE */
360 -- -----------------------------------------------------------------------------
361 -- toCalendarTime t converts t to a local time, modified by
362 -- the current timezone and daylight savings time settings. toUTCTime
363 -- t converts t into UTC time. toClockTime l converts l into the
364 -- corresponding internal ClockTime. The wday, yday, tzname, and isdst fields
368 toCalendarTime :: ClockTime -> IO CalendarTime
369 toCalendarTime = clockToCalendarTime localtime False
371 toUTCTime :: ClockTime -> CalendarTime
372 toUTCTime = unsafePerformIO . clockToCalendarTime gmtime True
374 -- ToDo: should be made thread safe, because localtime uses static storage,
375 -- or use the localtime_r version.
376 clockToCalendarTime :: (Ptr CTime -> IO (Ptr CTm)) -> Bool -> ClockTime
378 clockToCalendarTime fun is_utc (TOD secs psec) = do
379 withObject (fromIntegral secs :: CTime) $ \ p_timer -> do
380 p_tm <- fun p_timer -- can't fail, according to POSIX
381 sec <- (#peek struct tm,tm_sec ) p_tm :: IO CInt
382 min <- (#peek struct tm,tm_min ) p_tm :: IO CInt
383 hour <- (#peek struct tm,tm_hour ) p_tm :: IO CInt
384 mday <- (#peek struct tm,tm_mday ) p_tm :: IO CInt
385 mon <- (#peek struct tm,tm_mon ) p_tm :: IO CInt
386 year <- (#peek struct tm,tm_year ) p_tm :: IO CInt
387 wday <- (#peek struct tm,tm_wday ) p_tm :: IO CInt
388 yday <- (#peek struct tm,tm_yday ) p_tm :: IO CInt
389 isdst <- (#peek struct tm,tm_isdst) p_tm :: IO CInt
393 tzname <- peekCString zone
395 let month | mon >= 0 && mon <= 11 = toEnum (fromIntegral mon)
396 | otherwise = error ("toCalendarTime: illegal month value: " ++ show mon)
399 (1900 + fromIntegral year)
406 (toEnum (fromIntegral wday))
408 (if is_utc then "UTC" else tzname)
409 (if is_utc then 0 else fromIntegral tz)
410 (if is_utc then False else isdst /= 0))
413 toClockTime :: CalendarTime -> ClockTime
414 toClockTime (CalendarTime year mon mday hour min sec psec
415 _wday _yday _tzname tz isdst) =
417 -- `isDst' causes the date to be wrong by one hour...
418 -- FIXME: check, whether this works on other arch's than Linux, too...
420 -- so we set it to (-1) (means `unknown') and let `mktime' determine
422 let isDst = -1 :: CInt in -- if isdst then (1::Int) else 0
424 if psec < 0 || psec > 999999999999 then
425 error "Time.toClockTime: picoseconds out of range"
426 else if tz < -43200 || tz > 43200 then
427 error "Time.toClockTime: timezone offset out of range"
430 allocaBytes (#const sizeof(struct tm)) $ \ p_tm -> do
431 (#poke struct tm,tm_sec ) p_tm (fromIntegral sec :: CInt)
432 (#poke struct tm,tm_min ) p_tm (fromIntegral min :: CInt)
433 (#poke struct tm,tm_hour ) p_tm (fromIntegral hour :: CInt)
434 (#poke struct tm,tm_mday ) p_tm (fromIntegral mday :: CInt)
435 (#poke struct tm,tm_mon ) p_tm (fromIntegral (fromEnum mon) :: CInt)
436 (#poke struct tm,tm_year ) p_tm (fromIntegral year - 1900 :: CInt)
437 (#poke struct tm,tm_isdst) p_tm isDst
438 t <- throwIf (== -1) (\_ -> "Time.toClockTime: invalid input")
441 -- mktime expects its argument to be in the local timezone, but
442 -- toUTCTime makes UTC-encoded CalendarTime's ...
444 -- Since there is no any_tz_struct_tm-to-time_t conversion
445 -- function, we have to fake one... :-) If not in all, it works in
446 -- most cases (before, it was the other way round...)
448 -- Luckily, mktime tells us, what it *thinks* the timezone is, so,
449 -- to compensate, we add the timezone difference to mktime's
452 gmtoff <- gmtoff p_tm
453 let res = fromIntegral t - tz + fromIntegral gmtoff
454 return (TOD (fromIntegral res) 0)
456 -- -----------------------------------------------------------------------------
457 -- Converting time values to strings.
459 calendarTimeToString :: CalendarTime -> String
460 calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
462 formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
463 formatCalendarTime l fmt (CalendarTime year mon day hour min sec _
464 wday yday tzname _ _) =
466 where doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
467 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
468 doFmt ('%':c:cs) = decode c ++ doFmt cs
469 doFmt (c:cs) = c : doFmt cs
472 decode 'A' = fst (wDays l !! fromEnum wday) -- day of the week, full name
473 decode 'a' = snd (wDays l !! fromEnum wday) -- day of the week, abbrev.
474 decode 'B' = fst (months l !! fromEnum mon) -- month, full name
475 decode 'b' = snd (months l !! fromEnum mon) -- month, abbrev
476 decode 'h' = snd (months l !! fromEnum mon) -- ditto
477 decode 'C' = show2 (year `quot` 100) -- century
478 decode 'c' = doFmt (dateTimeFmt l) -- locale's data and time format.
479 decode 'D' = doFmt "%m/%d/%y"
480 decode 'd' = show2 day -- day of the month
481 decode 'e' = show2' day -- ditto, padded
482 decode 'H' = show2 hour -- hours, 24-hour clock, padded
483 decode 'I' = show2 (to12 hour) -- hours, 12-hour clock
484 decode 'j' = show3 yday -- day of the year
485 decode 'k' = show2' hour -- hours, 24-hour clock, no padding
486 decode 'l' = show2' (to12 hour) -- hours, 12-hour clock, no padding
487 decode 'M' = show2 min -- minutes
488 decode 'm' = show2 (fromEnum mon+1) -- numeric month
490 decode 'p' = (if hour < 12 then fst else snd) (amPm l) -- am or pm
491 decode 'R' = doFmt "%H:%M"
492 decode 'r' = doFmt (time12Fmt l)
493 decode 'T' = doFmt "%H:%M:%S"
495 decode 'S' = show2 sec -- seconds
496 decode 's' = show2 sec -- number of secs since Epoch. (ToDo.)
497 decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7) -- week number, starting on Sunday.
498 decode 'u' = show (let n = fromEnum wday in -- numeric day of the week (1=Monday, 7=Sunday)
499 if n == 0 then 7 else n)
500 decode 'V' = -- week number (as per ISO-8601.)
501 let (week, days) = -- [yep, I've always wanted to be able to display that too.]
502 (yday + 7 - if fromEnum wday > 0 then
503 fromEnum wday - 1 else 6) `divMod` 7
504 in show2 (if days >= 4 then
506 else if week == 0 then 53 else week)
508 decode 'W' = -- week number, weeks starting on monday
509 show2 ((yday + 7 - if fromEnum wday > 0 then
510 fromEnum wday - 1 else 6) `div` 7)
511 decode 'w' = show (fromEnum wday) -- numeric day of the week, weeks starting on Sunday.
512 decode 'X' = doFmt (timeFmt l) -- locale's preferred way of printing time.
513 decode 'x' = doFmt (dateFmt l) -- locale's preferred way of printing dates.
514 decode 'Y' = show year -- year, including century.
515 decode 'y' = show2 (year `rem` 100) -- year, within century.
516 decode 'Z' = tzname -- timezone name
521 show2, show2', show3 :: Int -> String
523 | x' < 10 = '0': show x'
524 | otherwise = show x'
525 where x' = x `rem` 100
528 | x' < 10 = ' ': show x'
529 | otherwise = show x'
530 where x' = x `rem` 100
532 show3 x = show (x `quot` 100) ++ show2 (x `rem` 100)
533 where x' = x `rem` 1000
536 to12 h = let h' = h `mod` 12 in if h' == 0 then 12 else h'
538 -- Useful extensions for formatting TimeDiffs.
540 timeDiffToString :: TimeDiff -> String
541 timeDiffToString = formatTimeDiff defaultTimeLocale "%c"
543 formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String
544 formatTimeDiff l fmt td@(TimeDiff year month day hour min sec _)
548 doFmt ('%':'-':cs) = doFmt ('%':cs) -- padding not implemented
549 doFmt ('%':'_':cs) = doFmt ('%':cs) -- padding not implemented
550 doFmt ('%':c:cs) = decode c ++ doFmt cs
551 doFmt (c:cs) = c : doFmt cs
555 'B' -> fst (months l !! fromEnum month)
556 'b' -> snd (months l !! fromEnum month)
557 'h' -> snd (months l !! fromEnum month)
558 'c' -> defaultTimeDiffFmt td
559 'C' -> show2 (year `quot` 100)
560 'D' -> doFmt "%m/%d/%y"
564 'I' -> show2 (to12 hour)
566 'l' -> show2' (to12 hour)
568 'm' -> show2 (fromEnum month + 1)
570 'p' -> (if hour < 12 then fst else snd) (amPm l)
572 'r' -> doFmt (time12Fmt l)
573 'T' -> doFmt "%H:%M:%S"
576 's' -> show2 sec -- Implementation-dependent, sez the lib doc..
577 'X' -> doFmt (timeFmt l)
578 'x' -> doFmt (dateFmt l)
580 'y' -> show2 (year `rem` 100)
584 defaultTimeDiffFmt (TimeDiff year month day hour min sec _) =
585 foldr (\ (v,s) rest ->
587 then show v ++ ' ':(addS v s)
588 ++ if null rest then "" else ", "
592 (zip [year, month, day, hour, min, sec] (intervals l))
594 addS v s = if abs v == 1 then fst s else snd s
597 -- -----------------------------------------------------------------------------
598 -- Foreign time interface (POSIX)
600 type CTm = () -- struct tm
602 foreign import unsafe localtime :: Ptr CTime -> IO (Ptr CTm)
603 foreign import unsafe gmtime :: Ptr CTime -> IO (Ptr CTm)
604 foreign import unsafe mktime :: Ptr CTm -> IO CTime
605 foreign import unsafe time :: Ptr CTime -> IO CTime
607 #if HAVE_GETTIMEOFDAY
609 foreign import unsafe gettimeofday :: Ptr CTimeVal -> Ptr () -> IO CInt
614 #ifndef mingw32_TARGET_OS
615 foreign import unsafe ftime :: Ptr CTimeB -> IO CInt
617 foreign import unsafe ftime :: Ptr CTimeB -> IO ()