-- | ISO 8601 Ordinal Date format module Data.Time.Calendar.OrdinalDate where import Data.Time.Calendar.Days import Data.Time.Calendar.Private -- | convert to ISO 8601 Ordinal Date format. First element of result is year (proleptic Gregoran calendar), -- second is the day of the year, with 1 for Jan 1, and 365 (or 366 in leap years) for Dec 31. toOrdinalDate :: Day -> (Integer,Int) toOrdinalDate (ModifiedJulianDay mjd) = (year,yd) where a = mjd + 678575 quadcent = div a 146097 b = mod a 146097 cent = min (div b 36524) 3 c = b - (cent * 36524) quad = div c 1461 d = mod c 1461 y = min (div d 365) 3 yd = fromInteger (d - (y * 365) + 1) year = quadcent * 400 + cent * 100 + quad * 4 + y + 1 -- | convert from ISO 8601 Ordinal Date format. -- Invalid day numbers will be clipped to the correct range (1 to 365 or 366). fromOrdinalDate :: Integer -> Int -> Day fromOrdinalDate year day = ModifiedJulianDay mjd where y = year - 1 mjd = (fromIntegral (clip 1 (if isLeapYear year then 366 else 365) day)) + (365 * y) + (div y 4) - (div y 100) + (div y 400) - 678576 -- | show in ISO 8601 Ordinal Date format (yyyy-ddd) showOrdinalDate :: Day -> String showOrdinalDate date = (show4 y) ++ "-" ++ (show3 d) where (y,d) = toOrdinalDate date -- | Is this year a leap year according to the proleptic Gregorian calendar? isLeapYear :: Integer -> Bool isLeapYear year = (mod year 4 == 0) && ((mod year 400 == 0) || not (mod year 100 == 0)) -- | Get the number of the Monday-starting week in the year and the day of the week. -- The first Monday is the first day of week 1, any earlier days in the year are week 0 (as \"%W\" in 'Data.Time.Format.formatTime'). -- Monday is 1, Sunday is 7 (as \"%u\" in 'Data.Time.Format.formatTime'). mondayStartWeek :: Day -> (Int,Int) mondayStartWeek date = (fromInteger ((div d 7) - (div k 7)),fromInteger (mod d 7) + 1) where yd = snd (toOrdinalDate date) d = (toModifiedJulianDay date) + 2 k = d - (toInteger yd) -- | Get the number of the Sunday-starting week in the year and the day of the week. -- The first Sunday is the first day of week 1, any earlier days in the year are week 0 (as \"%U\" in 'Data.Time.Format.formatTime'). -- Sunday is 0, Saturday is 6 (as \"%w\" in 'Data.Time.Format.formatTime'). sundayStartWeek :: Day -> (Int,Int) sundayStartWeek date =(fromInteger ((div d 7) - (div k 7)),fromInteger (mod d 7)) where yd = snd (toOrdinalDate date) d = (toModifiedJulianDay date) + 3 k = d - (toInteger yd) -- | The inverse of 'mondayStartWeek'. Get a 'Day' given the year, -- the number of the Monday-starting week, and the day of the week. -- The first Monday is the first day of week 1, any earlier days in the year -- are week 0 (as \"%W\" in 'Data.Time.Format.formatTime'). fromMondayStartWeek :: Integer -- ^ Year. -> Int -- ^ Monday-starting week number. -> Int -- ^ Day of week. -- Monday is 1, Sunday is 7 (as \"%u\" in 'Data.Time.Format.formatTime'). -> Day fromMondayStartWeek y w d = ModifiedJulianDay (firstDay + yd) where yd = firstMonday + 7 * toInteger (w-1) + toInteger d - 1 -- first day of the year firstDay = toModifiedJulianDay (fromOrdinalDate y 1) -- 0-based year day of first monday of the year firstMonday = (5 - firstDay) `mod` 7 -- | The inverse of 'sundayStartWeek'. Get a 'Day' given the year and -- the number of the day of a Sunday-starting week. -- The first Sunday is the first day of week 1, any earlier days in the -- year are week 0 (as \"%U\" in 'Data.Time.Format.formatTime'). fromSundayStartWeek :: Integer -- ^ Year. -> Int -- ^ Sunday-starting week number. -> Int -- ^ Day of week -- Sunday is 0, Saturday is 6 (as \"%w\" in 'Data.Time.Format.formatTime'). -> Day fromSundayStartWeek y w d = ModifiedJulianDay (firstDay + yd) where yd = firstSunday + 7 * toInteger (w-1) + toInteger d -- first day of the year firstDay = toModifiedJulianDay (fromOrdinalDate y 1) -- 0-based year day of first sunday of the year firstSunday = (4 - firstDay) `mod` 7