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+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1995-97
+%
+\section[Time]{Haskell 1.4 Time of Day Library}
+
+The {\em Time} library provides standard functionality for
+clock times, including timezone information (i.e, the functionality of
+"time.h", adapted to the Haskell environment), It follows RFC 1129 in
+its use of Coordinated Universal Time (UTC).
+
+\begin{code}
+module Time
+ (
+ CalendarTime(..),
+ Month,
+ Day,
+ CalendarTime(CalendarTime),
+ TimeDiff(TimeDiff),
+ ClockTime,
+ getClockTime, addToClockTime, diffClockTimes,
+ toCalendarTime, toUTCTime, toClockTime,
+ calendarToTimeString, formatCalendarTime
+ ) where
+
+import PrelBase
+import ST
+import IOBase ( IOError(..), constructErrorAndFail )
+import ArrBase
+import STBase
+
+import PackedString (unpackPS, packCBytesST)
+import PosixUtil (allocWords, allocChars)
+\end{code}
+
+One way to partition and give name to chunks of a year and a week:
+
+\begin{code}
+data Month
+ = January | February | March | April
+ | May | June | July | August
+ | September | October | November | December
+ deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
+
+data Day
+ = Sunday | Monday | Tuesday | Wednesday
+ | Thursday | Friday | Saturday
+ deriving (Eq, Ord, Enum, Bounded, Ix, Read, Show)
+
+\end{code}
+
+@ClockTime@ is an abstract type, used for the internal clock time.
+Clock times may be compared, converted to strings, or converted to an
+external calendar time @CalendarTime@.
+
+\begin{code}
+data ClockTime = TOD Integer Integer
+ deriving (Eq, Ord)
+\end{code}
+
+When a @ClockTime@ is shown, it is converted to a string of the form
+@"Mon Nov 28 21:45:41 GMT 1994"@.
+
+For now, we are restricted to roughly:
+Fri Dec 13 20:45:52 1901 through Tue Jan 19 03:14:07 2038, because
+we use the C library routines based on 32 bit integers.
+
+\begin{code}
+instance Show ClockTime where
+ showsPrec p (TOD sec@(J# a# s# d#) nsec) = showString $ unsafePerformPrimIO $
+ allocChars 32 >>= \ buf ->
+ _ccall_ showTime (I# s#) (ByteArray bottom d#) buf
+ >>= \ str ->
+ _ccall_ strlen str >>= \ len ->
+ packCBytesST len str >>= \ ps ->
+ return (unpackPS ps)
+
+ showList = showList__ (showsPrec 0)
+\end{code}
+
+
+@CalendarTime@ is a user-readable and manipulable
+representation of the internal $ClockTime$ type. The
+numeric fields have the following ranges.
+
+\begin{verbatim}
+Value Range Comments
+----- ----- --------
+
+year -maxInt .. maxInt [Pre-Gregorian dates are inaccurate]
+mon 0 .. 11 [Jan = 0, Dec = 11]
+day 1 .. 31
+hour 0 .. 23
+min 0 .. 59
+sec 0 .. 61 [Allows for two leap seconds]
+picosec 0 .. (10^12)-1 [This could be over-precise?]
+wday 0 .. 6 [Sunday = 0, Saturday = 6]
+yday 0 .. 365 [364 in non-Leap years]
+tz -43200 .. 43200 [Variation from UTC in seconds]
+\end{verbatim}
+
+The {\em tzname} field is the name of the time zone. The {\em isdst}
+field indicates whether Daylight Savings Time would be in effect.
+
+\begin{code}
+data CalendarTime
+ = CalendarTime {
+ ctYear :: Int,
+ ctMonth :: Int,
+ ctDay :: Int,
+ ctHour :: Int,
+ ctMin :: Int,
+ ctSec :: Int,
+ ctPicosec :: Integer,
+ ctWDay :: Day,
+ ctYDay :: Int,
+ ctTZName :: String,
+ ctTZ :: Int,
+ ctIsDST :: Bool
+ }
+ deriving (Eq,Ord,Read,Show)
+
+\end{code}
+
+The @TimeDiff@ type records the difference between two clock times in
+a user-readable way.
+
+\begin{code}
+data TimeDiff
+ = TimeDiff {
+ tdYear :: Int,
+ tdMonth :: Int,
+ tdDay :: Int,
+ tdHour :: Int,
+ tdMin :: Int,
+ tdSec :: Int,
+ tdPicosec :: Integer -- not standard
+ }
+ deriving (Eq,Ord,Read,Show)
+\end{code}
+
+@getClockTime@ returns the current time in its internal representation.
+
+\begin{code}
+getClockTime :: IO ClockTime
+getClockTime =
+ malloc1 `thenIO_Prim` \ i1 ->
+ malloc1 `thenIO_Prim` \ i2 ->
+ _ccall_ getClockTime i1 i2 `thenIO_Prim` \ rc ->
+ if rc == 0 then
+ cvtUnsigned i1 `thenIO_Prim` \ sec ->
+ cvtUnsigned i2 `thenIO_Prim` \ nsec ->
+ return (TOD sec (nsec * 1000))
+ else
+ constructErrorAndFail "getClockTime"
+ where
+ malloc1 = ST $ \ (S# s#) ->
+ case newIntArray# 1# s# of
+ StateAndMutableByteArray# s2# barr# -> (MutableByteArray bottom barr#, S# s2#)
+
+ -- The C routine fills in an unsigned word. We don't have `unsigned2Integer#,'
+ -- so we freeze the data bits and use them for an MP_INT structure. Note that
+ -- zero is still handled specially, although (J# 1# 1# (ptr to 0#)) is probably
+ -- acceptable to gmp.
+
+ cvtUnsigned (MutableByteArray _ arr#) = ST $ \ (S# s#) ->
+ case readIntArray# arr# 0# s# of
+ StateAndInt# s2# r# ->
+ if r# ==# 0# then
+ (0, S# s2#)
+ else
+ case unsafeFreezeByteArray# arr# s2# of
+ StateAndByteArray# s3# frozen# -> (J# 1# 1# frozen#, S# s3#)
+
+\end{code}
+
+@addToClockTime@ {\em d} {\em t} adds a time difference {\em d} and a
+clock time {\em t} to yield a new clock time. The difference {\em d}
+may be either positive or negative. @[diffClockTimes@ {\em t1} {\em
+t2} returns the difference between two clock times {\em t1} and {\em
+t2} as a @TimeDiff@.
+
+
+\begin{code}
+addToClockTime :: TimeDiff -> ClockTime -> ClockTime
+addToClockTime (TimeDiff year mon day hour min sec psec)
+ (TOD c_sec c_psec) = unsafePerformPrimIO $
+ allocWords (``sizeof(time_t)'') >>= \ res ->
+ _ccall_ toClockSec year mon day hour min sec 1 res
+ >>= \ ptr@(A# ptr#) ->
+ if ptr /= ``NULL'' then
+ let
+ diff_sec = (int2Integer# (indexIntOffAddr# ptr# 0#))
+ diff_psec = psec
+ in
+ return (TOD (c_sec + diff_sec) (c_psec + diff_psec))
+ else
+ error "Time.addToClockTime: can't perform conversion of TimeDiff"
+
+
+diffClockTimes :: ClockTime -> ClockTime -> TimeDiff
+diffClockTimes tod_a tod_b =
+ let
+ CalendarTime year_a mon_a day_a hour_a min_a sec_a psec_a _ _ _ _ _ = toCalendarTime tod_a
+ CalendarTime year_b mon_b day_b hour_b min_b sec_b psec_b _ _ _ _ _ = toCalendarTime tod_b
+ in
+ TimeDiff (year_a - year_b)
+ (mon_a - mon_b)
+ (day_a - day_b)
+ (hour_a - hour_b)
+ (min_b - min_a)
+ (sec_a - sec_b)
+ (psec_a - psec_b)
+\end{code}
+
+@toCalendarTime@ {\em t} converts {\em t} to a local time, modified by
+the current timezone and daylight savings time settings. @toUTCTime@
+{\em t} converts {\em t} into UTC time. @toClockTime@ {\em l}
+converts {\em l} into the corresponding internal @ClockTime@. The
+{\em wday}, {\em yday}, {\em tzname}, and {\em isdst} fields are
+ignored.
+
+\begin{code}
+toCalendarTime :: ClockTime -> CalendarTime
+toCalendarTime (TOD sec@(J# a# s# d#) psec) = unsafePerformPrimIO $
+ allocWords (``sizeof(struct tm)''::Int) >>= \ res ->
+ allocChars 32 >>= \ zoneNm ->
+ _casm_ ``SETZONE((struct tm *)%0,(char *)%1); '' res zoneNm >>= \ () ->
+ _ccall_ toLocalTime (I# s#) (ByteArray bottom d#) res
+ >>= \ tm ->
+ if tm == (``NULL''::Addr) then
+ error "Time.toCalendarTime: out of range"
+ else
+ _casm_ ``%r = ((struct tm *)%0)->tm_sec;'' tm >>= \ sec ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_min;'' tm >>= \ min ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_hour;'' tm >>= \ hour ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_mday;'' tm >>= \ mday ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_mon;'' tm >>= \ mon ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_year;'' tm >>= \ year ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_wday;'' tm >>= \ wday ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_yday;'' tm >>= \ yday ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_isdst;'' tm >>= \ isdst ->
+ _ccall_ ZONE tm >>= \ zone ->
+ _ccall_ GMTOFF tm >>= \ tz ->
+ _ccall_ strlen zone >>= \ len ->
+ packCBytesST len zone >>= \ tzname ->
+ returnPrimIO (CalendarTime (1900+year) mon mday hour min sec psec
+ wday yday (unpackPS tzname) tz (isdst /= 0))
+
+toUTCTime :: ClockTime -> CalendarTime
+toUTCTime (TOD sec@(J# a# s# d#) psec) = unsafePerformPrimIO (
+ allocWords (``sizeof(struct tm)''::Int) >>= \ res ->
+ allocChars 32 >>= \ zoneNm ->
+ _casm_ ``SETZONE((struct tm *)%0,(char *)%1); '' res zoneNm >>= \ () ->
+ _ccall_ toUTCTime (I# s#) (ByteArray bottom d#) res
+ >>= \ tm ->
+ if tm == (``NULL''::Addr) then
+ error "Time.toUTCTime: out of range"
+ else
+ _casm_ ``%r = ((struct tm *)%0)->tm_sec;'' tm >>= \ sec ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_min;'' tm >>= \ min ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_hour;'' tm >>= \ hour ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_mday;'' tm >>= \ mday ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_mon;'' tm >>= \ mon ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_year;'' tm >>= \ year ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_wday;'' tm >>= \ wday ->
+ _casm_ ``%r = ((struct tm *)%0)->tm_yday;'' tm >>= \ yday ->
+ returnPrimIO (CalendarTime (1900+year) mon mday hour min sec psec
+ wday yday "UTC" 0 False)
+ )
+
+toClockTime :: CalendarTime -> ClockTime
+toClockTime (CalendarTime year mon mday hour min sec psec wday yday tzname tz isdst) =
+ if psec < 0 || psec > 999999999999 then
+ error "Time.toClockTime: picoseconds out of range"
+ else if tz < -43200 || tz > 43200 then
+ error "Time.toClockTime: timezone offset out of range"
+ else
+ unsafePerformPrimIO (
+ allocWords (``sizeof(time_t)'') >>= \ res ->
+ _ccall_ toClockSec year mon mday hour min sec tz res
+ >>= \ ptr@(A# ptr#) ->
+ if ptr /= ``NULL'' then
+ returnPrimIO (TOD (int2Integer# (indexIntOffAddr# ptr# 0#)) psec)
+ else
+ error "Time.toClockTime: can't perform conversion"
+ )
+
+bottom :: (Int,Int)
+bottom = error "Time.bottom"
+\end{code}
+
+\begin{code}
+calendarTimeToString :: CalendarTime -> String
+calendarTimeToString = formatCalendarTime defaultTimeLocale "%c"
+
+formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String
+formatCalendarTime l
+ fmt
+ ct@(CalendarTime
+ year mon
+ day hour
+ min sec
+ sdec
+ wday yday tzname _ _)
+ = doFmt fmt
+ where
+ doFmt ('%':c:cs) = decode c ++ doFmt cs
+ doFmt (c:cs) = c : doFmt cs
+ doFmt "" = ""
+
+ to12 h = let h' = h `mod` 12 in if h == 0 then 12 else h
+
+ decode 'A' = fst (wdays l !! fromEnum wday)
+ decode 'a' = snd (wdays l !! fromEnum wday)
+ decode 'B' = fst (months l !! fromEnum mon)
+ decode 'b' = snd (months l !! fromEnum mon)
+ decode 'h' = snd (months l !! fromEnum mon)
+ decode 'C' = show2 (year `quot` 100)
+ decode 'c' = doFmt (dateTimeFmt l)
+ decode 'D' = doFmt "%m/%d/%y"
+ decode 'd' = show2 day
+ decode 'e' = show2' day
+ decode 'H' = show2 hour
+ decode 'I' = show2 (to12 hour)
+ decode 'j' = show3 yday
+ decode 'k' = show2' hour
+ decode 'l' = show2' (to12 hour)
+ decode 'M' = show2 min
+ decode 'm' = show2 (fromEnum mon+1)
+ decode 'n' = "\n"
+ decode 'p' = (if hour < 12 then fst else snd) (amPm l)
+ decode 'R' = doFmt "%H:%M"
+ decode 'r' = doFmt (time12Fmt l)
+ decode 'T' = doFmt "%H:%M:%S"
+ decode 't' = "\t"
+ decode 'S' = show2 sec
+ decode 's' = show2 sec -- Implementation-dependent, sez the lib doc..
+ decode 'U' = show2 ((yday + 7 - fromEnum wday) `div` 7)
+ decode 'u' = show (let n = fromEnum wday in if n == 0 then 7 else n)
+ decode 'V' =
+ let (week, days) =
+ (yday + 7 - if fromEnum wday > 0 then
+ fromEnum wday - 1 else 6) `divMod` 7
+ in
+ show2 (if days >= 4
+ then week+1
+ else if week == 0 then 53 else week)
+ decode 'W' =
+ show2 ((yday + 7 - if fromEnum wday > 0 then
+ fromEnum wday - 1 else 6) `div` 7)
+ decode 'w' = show (fromEnum wday)
+ decode 'X' = doFmt (timeFmt l)
+ decode 'x' = doFmt (dateFmt l)
+ decode 'Y' = show year
+ decode 'y' = show2 (year `rem` 100)
+ decode 'Z' = tzname
+ decode '%' = "%"
+ decode c = [c]
+
+show2, show2', show3 :: Int -> String
+show2 x = [intToDigit (x `quot` 10), intToDigit (x `rem` 10)]
+show2' x = if x < 10 then [ ' ', intToDigit x] else show2 x
+show3 x = intToDigit (x `quot` 100) : show2 (x `rem` 100)
+
+\end{code}