------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- A D A . C A L E N D A R -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2007, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Ada.Unchecked_Conversion; with System.OS_Primitives; -- used for Clock package body Ada.Calendar is -------------------------- -- Implementation Notes -- -------------------------- -- In complex algorithms, some variables of type Ada.Calendar.Time carry -- suffix _S or _N to denote units of seconds or nanoseconds. -- -- Because time is measured in different units and from different origins -- on various targets, a system independent model is incorporated into -- Ada.Calendar. The idea behind the design is to encapsulate all target -- dependent machinery in a single package, thus providing a uniform -- interface to all existing and any potential children. -- package Ada.Calendar -- procedure Split (5 parameters) -------+ -- | Call from local routine -- private | -- package Formatting_Operations | -- procedure Split (11 parameters) <--+ -- end Formatting_Operations | -- end Ada.Calendar | -- | -- package Ada.Calendar.Formatting | Call from child routine -- procedure Split (9 or 10 parameters) -+ -- end Ada.Calendar.Formatting -- The behaviour of the interfacing routines is controlled via various -- flags. All new Ada 2005 types from children of Ada.Calendar are -- emulated by a similar type. For instance, type Day_Number is replaced -- by Integer in various routines. One ramification of this model is that -- the caller site must perform validity checks on returned results. -- The end result of this model is the lack of target specific files per -- child of Ada.Calendar (a-calfor, a-calfor-vms, a-calfor-vxwors, etc). ----------------------- -- Local Subprograms -- ----------------------- procedure Check_Within_Time_Bounds (T : Time_Rep); -- Ensure that a time representation value falls withing the bounds of Ada -- time. Leap seconds support is taken into account. procedure Cumulative_Leap_Seconds (Start_Date : Time_Rep; End_Date : Time_Rep; Elapsed_Leaps : out Natural; Next_Leap : out Time_Rep); -- Elapsed_Leaps is the sum of the leap seconds that have occured on or -- after Start_Date and before (strictly before) End_Date. Next_Leap_Sec -- represents the next leap second occurence on or after End_Date. If -- there are no leaps seconds after End_Date, End_Of_Time is returned. -- End_Of_Time can be used as End_Date to count all the leap seconds that -- have occured on or after Start_Date. -- -- Note: Any sub seconds of Start_Date and End_Date are discarded before -- the calculations are done. For instance: if 113 seconds is a leap -- second (it isn't) and 113.5 is input as an End_Date, the leap second -- at 113 will not be counted in Leaps_Between, but it will be returned -- as Next_Leap_Sec. Thus, if the caller wants to know if the End_Date is -- a leap second, the comparison should be: -- -- End_Date >= Next_Leap_Sec; -- -- After_Last_Leap is designed so that this comparison works without -- having to first check if Next_Leap_Sec is a valid leap second. function Duration_To_Time_Rep is new Ada.Unchecked_Conversion (Duration, Time_Rep); -- Convert a duration value into a time representation value function Time_Rep_To_Duration is new Ada.Unchecked_Conversion (Time_Rep, Duration); -- Convert a time representation value into a duration value ----------------- -- Local Types -- ----------------- -- An integer time duration. The type is used whenever a positive elapsed -- duration is needed, for instance when splitting a time value. Here is -- how Time_Rep and Time_Dur are related: -- 'First Ada_Low Ada_High 'Last -- Time_Rep: +-------+------------------------+---------+ -- Time_Dur: +------------------------+---------+ -- 0 'Last type Time_Dur is range 0 .. 2 ** 63 - 1; --------------------- -- Local Constants -- --------------------- -- Currently none of the GNAT targets support leap seconds. At some point -- it might be necessary to query a C function to determine if the target -- supports leap seconds, but for now this is deemed unnecessary. Leap_Support : constant Boolean := False; Leap_Seconds_Count : constant Natural := 23; Ada_Min_Year : constant Year_Number := Year_Number'First; Secs_In_Four_Years : constant := (3 * 365 + 366) * Secs_In_Day; Secs_In_Non_Leap_Year : constant := 365 * Secs_In_Day; -- Lower and upper bound of Ada time. The zero (0) value of type Time is -- positioned at year 2150. Note that the lower and upper bound account -- for the non-leap centenial years. Ada_Low : constant Time_Rep := -(61 * 366 + 188 * 365) * Nanos_In_Day; Ada_High : constant Time_Rep := (60 * 366 + 190 * 365) * Nanos_In_Day; -- Even though the upper bound of time is 2399-12-31 23:59:59.999999999 -- UTC, it must be increased to include all leap seconds. Ada_High_And_Leaps : constant Time_Rep := Ada_High + Time_Rep (Leap_Seconds_Count) * Nano; -- Two constants used in the calculations of elapsed leap seconds. -- End_Of_Time is later than Ada_High in time zone -28. Start_Of_Time -- is earlier than Ada_Low in time zone +28. End_Of_Time : constant Time_Rep := Ada_High + Time_Rep (3) * Nanos_In_Day; Start_Of_Time : constant Time_Rep := Ada_Low - Time_Rep (3) * Nanos_In_Day; -- The Unix lower time bound expressed as nanoseconds since the -- start of Ada time in UTC. Unix_Min : constant Time_Rep := Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day; Cumulative_Days_Before_Month : constant array (Month_Number) of Natural := (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334); Leap_Second_Times : array (1 .. Leap_Seconds_Count) of Time_Rep; -- Each value represents a time value which is one second before a leap -- second occurence. This table is populated during the elaboration of -- Ada.Calendar. --------- -- "+" -- --------- function "+" (Left : Time; Right : Duration) return Time is pragma Unsuppress (Overflow_Check); Left_N : constant Time_Rep := Time_Rep (Left); Res_N : Time_Rep; begin -- Trivial case if Right = Duration (0.0) then return Left; end if; Res_N := Left_N + Duration_To_Time_Rep (Right); Check_Within_Time_Bounds (Res_N); return Time (Res_N); exception when Constraint_Error => raise Time_Error; end "+"; function "+" (Left : Duration; Right : Time) return Time is begin return Right + Left; end "+"; --------- -- "-" -- --------- function "-" (Left : Time; Right : Duration) return Time is pragma Unsuppress (Overflow_Check); Left_N : constant Time_Rep := Time_Rep (Left); Res_N : Time_Rep; begin -- Trivial case if Right = Duration (0.0) then return Left; end if; Res_N := Left_N - Duration_To_Time_Rep (Right); Check_Within_Time_Bounds (Res_N); return Time (Res_N); exception when Constraint_Error => raise Time_Error; end "-"; function "-" (Left : Time; Right : Time) return Duration is pragma Unsuppress (Overflow_Check); -- The bounds of type Duration expressed as time representations Dur_Low : constant Time_Rep := Duration_To_Time_Rep (Duration'First); Dur_High : constant Time_Rep := Duration_To_Time_Rep (Duration'Last); Res_N : Time_Rep; begin Res_N := Time_Rep (Left) - Time_Rep (Right); -- The result does not fit in a duration value if Res_N < Dur_Low or else Res_N > Dur_High then raise Time_Error; end if; return Time_Rep_To_Duration (Res_N); exception when Constraint_Error => raise Time_Error; end "-"; --------- -- "<" -- --------- function "<" (Left, Right : Time) return Boolean is begin return Time_Rep (Left) < Time_Rep (Right); end "<"; ---------- -- "<=" -- ---------- function "<=" (Left, Right : Time) return Boolean is begin return Time_Rep (Left) <= Time_Rep (Right); end "<="; --------- -- ">" -- --------- function ">" (Left, Right : Time) return Boolean is begin return Time_Rep (Left) > Time_Rep (Right); end ">"; ---------- -- ">=" -- ---------- function ">=" (Left, Right : Time) return Boolean is begin return Time_Rep (Left) >= Time_Rep (Right); end ">="; ------------------------------ -- Check_Within_Time_Bounds -- ------------------------------ procedure Check_Within_Time_Bounds (T : Time_Rep) is begin if Leap_Support then if T < Ada_Low or else T > Ada_High_And_Leaps then raise Time_Error; end if; else if T < Ada_Low or else T > Ada_High then raise Time_Error; end if; end if; end Check_Within_Time_Bounds; ----------- -- Clock -- ----------- function Clock return Time is Elapsed_Leaps : Natural; Next_Leap_N : Time_Rep; -- The system clock returns the time in UTC since the Unix Epoch of -- 1970-01-01 00:00:00.0. We perform an origin shift to the Ada Epoch -- by adding the number of nanoseconds between the two origins. Res_N : Time_Rep := Duration_To_Time_Rep (System.OS_Primitives.Clock) + Unix_Min; begin -- If the target supports leap seconds, determine the number of leap -- seconds elapsed until this moment. if Leap_Support then Cumulative_Leap_Seconds (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N); -- The system clock may fall exactly on a leap second if Res_N >= Next_Leap_N then Elapsed_Leaps := Elapsed_Leaps + 1; end if; -- The target does not support leap seconds else Elapsed_Leaps := 0; end if; Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano; return Time (Res_N); end Clock; ----------------------------- -- Cumulative_Leap_Seconds -- ----------------------------- procedure Cumulative_Leap_Seconds (Start_Date : Time_Rep; End_Date : Time_Rep; Elapsed_Leaps : out Natural; Next_Leap : out Time_Rep) is End_Index : Positive; End_T : Time_Rep := End_Date; Start_Index : Positive; Start_T : Time_Rep := Start_Date; begin -- Both input dates must be normalized to UTC pragma Assert (Leap_Support and then End_Date >= Start_Date); Next_Leap := End_Of_Time; -- Make sure that the end date does not excede the upper bound -- of Ada time. if End_Date > Ada_High then End_T := Ada_High; end if; -- Remove the sub seconds from both dates Start_T := Start_T - (Start_T mod Nano); End_T := End_T - (End_T mod Nano); -- Some trivial cases: -- Leap 1 . . . Leap N -- ---+========+------+############+-------+========+----- -- Start_T End_T Start_T End_T if End_T < Leap_Second_Times (1) then Elapsed_Leaps := 0; Next_Leap := Leap_Second_Times (1); return; elsif Start_T > Leap_Second_Times (Leap_Seconds_Count) then Elapsed_Leaps := 0; Next_Leap := End_Of_Time; return; end if; -- Perform the calculations only if the start date is within the leap -- second occurences table. if Start_T <= Leap_Second_Times (Leap_Seconds_Count) then -- 1 2 N - 1 N -- +----+----+-- . . . --+-------+---+ -- | T1 | T2 | | N - 1 | N | -- +----+----+-- . . . --+-------+---+ -- ^ ^ -- | Start_Index | End_Index -- +-------------------+ -- Leaps_Between -- The idea behind the algorithm is to iterate and find two -- closest dates which are after Start_T and End_T. Their -- corresponding index difference denotes the number of leap -- seconds elapsed. Start_Index := 1; loop exit when Leap_Second_Times (Start_Index) >= Start_T; Start_Index := Start_Index + 1; end loop; End_Index := Start_Index; loop exit when End_Index > Leap_Seconds_Count or else Leap_Second_Times (End_Index) >= End_T; End_Index := End_Index + 1; end loop; if End_Index <= Leap_Seconds_Count then Next_Leap := Leap_Second_Times (End_Index); end if; Elapsed_Leaps := End_Index - Start_Index; else Elapsed_Leaps := 0; end if; end Cumulative_Leap_Seconds; --------- -- Day -- --------- function Day (Date : Time) return Day_Number is Y : Year_Number; M : Month_Number; D : Day_Number; S : Day_Duration; begin Split (Date, Y, M, D, S); return D; end Day; ------------- -- Is_Leap -- ------------- function Is_Leap (Year : Year_Number) return Boolean is begin -- Leap centenial years if Year mod 400 = 0 then return True; -- Non-leap centenial years elsif Year mod 100 = 0 then return False; -- Regular years else return Year mod 4 = 0; end if; end Is_Leap; ----------- -- Month -- ----------- function Month (Date : Time) return Month_Number is Y : Year_Number; M : Month_Number; D : Day_Number; S : Day_Duration; begin Split (Date, Y, M, D, S); return M; end Month; ------------- -- Seconds -- ------------- function Seconds (Date : Time) return Day_Duration is Y : Year_Number; M : Month_Number; D : Day_Number; S : Day_Duration; begin Split (Date, Y, M, D, S); return S; end Seconds; ----------- -- Split -- ----------- procedure Split (Date : Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Seconds : out Day_Duration) is H : Integer; M : Integer; Se : Integer; Ss : Duration; Le : Boolean; begin -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will -- ensure that Split picks up the local time zone. Formatting_Operations.Split (Date => Date, Year => Year, Month => Month, Day => Day, Day_Secs => Seconds, Hour => H, Minute => M, Second => Se, Sub_Sec => Ss, Leap_Sec => Le, Is_Ada_05 => False, Time_Zone => 0); -- Validity checks if not Year'Valid or else not Month'Valid or else not Day'Valid or else not Seconds'Valid then raise Time_Error; end if; end Split; ------------- -- Time_Of -- ------------- function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Seconds : Day_Duration := 0.0) return Time is -- The values in the following constants are irrelevant, they are just -- placeholders; the choice of constructing a Day_Duration value is -- controlled by the Use_Day_Secs flag. H : constant Integer := 1; M : constant Integer := 1; Se : constant Integer := 1; Ss : constant Duration := 0.1; begin -- Validity checks if not Year'Valid or else not Month'Valid or else not Day'Valid or else not Seconds'Valid then raise Time_Error; end if; -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will -- ensure that Split picks up the local time zone. return Formatting_Operations.Time_Of (Year => Year, Month => Month, Day => Day, Day_Secs => Seconds, Hour => H, Minute => M, Second => Se, Sub_Sec => Ss, Leap_Sec => False, Use_Day_Secs => True, Is_Ada_05 => False, Time_Zone => 0); end Time_Of; ---------- -- Year -- ---------- function Year (Date : Time) return Year_Number is Y : Year_Number; M : Month_Number; D : Day_Number; S : Day_Duration; begin Split (Date, Y, M, D, S); return Y; end Year; -- The following packages assume that Time is a signed 64 bit integer -- type, the units are nanoseconds and the origin is the start of Ada -- time (1901-01-01 00:00:00.0 UTC). --------------------------- -- Arithmetic_Operations -- --------------------------- package body Arithmetic_Operations is --------- -- Add -- --------- function Add (Date : Time; Days : Long_Integer) return Time is pragma Unsuppress (Overflow_Check); Date_N : constant Time_Rep := Time_Rep (Date); Res_N : Time_Rep; begin -- Trivial case if Days = 0 then return Date; end if; Res_N := Date_N + Time_Rep (Days) * Nanos_In_Day; Check_Within_Time_Bounds (Res_N); return Time (Res_N); exception when Constraint_Error => raise Time_Error; end Add; ---------------- -- Difference -- ---------------- procedure Difference (Left : Time; Right : Time; Days : out Long_Integer; Seconds : out Duration; Leap_Seconds : out Integer) is Res_Dur : Time_Dur; Earlier : Time_Rep; Earlier_Sub : Time_Rep; Elapsed_Leaps : Natural; Later : Time_Rep; Later_Sub : Time_Rep; Negate : Boolean := False; Next_Leap_N : Time_Rep; Sub_Seconds : Duration; begin -- Both input time values are assumed to be in UTC if Left >= Right then Later := Time_Rep (Left); Earlier := Time_Rep (Right); else Later := Time_Rep (Right); Earlier := Time_Rep (Left); Negate := True; end if; -- If the target supports leap seconds, process them if Leap_Support then Cumulative_Leap_Seconds (Earlier, Later, Elapsed_Leaps, Next_Leap_N); if Later >= Next_Leap_N then Elapsed_Leaps := Elapsed_Leaps + 1; end if; -- The target does not support leap seconds else Elapsed_Leaps := 0; end if; -- Sub seconds Earlier_Sub := Earlier mod Nano; Later_Sub := Later mod Nano; if Later_Sub < Earlier_Sub then Later_Sub := Later_Sub + Time_Rep (1) * Nano; Later := Later - Time_Rep (1) * Nano; end if; Sub_Seconds := Duration (Later_Sub - Earlier_Sub) / Nano_F; Res_Dur := Time_Dur (Later / Nano - Earlier / Nano) - Time_Dur (Elapsed_Leaps); Days := Long_Integer (Res_Dur / Secs_In_Day); Seconds := Duration (Res_Dur mod Secs_In_Day) + Sub_Seconds; Leap_Seconds := Integer (Elapsed_Leaps); if Negate then Days := -Days; Seconds := -Seconds; if Leap_Seconds /= 0 then Leap_Seconds := -Leap_Seconds; end if; end if; end Difference; -------------- -- Subtract -- -------------- function Subtract (Date : Time; Days : Long_Integer) return Time is pragma Unsuppress (Overflow_Check); Date_N : constant Time_Rep := Time_Rep (Date); Res_N : Time_Rep; begin -- Trivial case if Days = 0 then return Date; end if; Res_N := Date_N - Time_Rep (Days) * Nanos_In_Day; Check_Within_Time_Bounds (Res_N); return Time (Res_N); exception when Constraint_Error => raise Time_Error; end Subtract; end Arithmetic_Operations; ---------------------- -- Delay_Operations -- ---------------------- package body Delays_Operations is ----------------- -- To_Duration -- ----------------- function To_Duration (Date : Time) return Duration is Elapsed_Leaps : Natural; Next_Leap_N : Time_Rep; Res_N : Time_Rep; begin Res_N := Time_Rep (Date); -- If the target supports leap seconds, remove any leap seconds -- elapsed upto the input date. if Leap_Support then Cumulative_Leap_Seconds (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N); -- The input time value may fall on a leap second occurence if Res_N >= Next_Leap_N then Elapsed_Leaps := Elapsed_Leaps + 1; end if; -- The target does not support leap seconds else Elapsed_Leaps := 0; end if; Res_N := Res_N - Time_Rep (Elapsed_Leaps) * Nano; -- Perform a shift in origins, note that enforcing type Time on -- both operands will invoke Ada.Calendar."-". return Time (Res_N) - Time (Unix_Min); end To_Duration; end Delays_Operations; --------------------------- -- Formatting_Operations -- --------------------------- package body Formatting_Operations is ----------------- -- Day_Of_Week -- ----------------- function Day_Of_Week (Date : Time) return Integer is Y : Year_Number; Mo : Month_Number; D : Day_Number; Ds : Day_Duration; H : Integer; Mi : Integer; Se : Integer; Su : Duration; Le : Boolean; Day_Count : Long_Integer; Res_Dur : Time_Dur; Res_N : Time_Rep; begin Formatting_Operations.Split (Date => Date, Year => Y, Month => Mo, Day => D, Day_Secs => Ds, Hour => H, Minute => Mi, Second => Se, Sub_Sec => Su, Leap_Sec => Le, Is_Ada_05 => True, Time_Zone => 0); -- Build a time value in the middle of the same day Res_N := Time_Rep (Formatting_Operations.Time_Of (Year => Y, Month => Mo, Day => D, Day_Secs => 0.0, Hour => 12, Minute => 0, Second => 0, Sub_Sec => 0.0, Leap_Sec => False, Use_Day_Secs => False, Is_Ada_05 => True, Time_Zone => 0)); -- Determine the elapsed seconds since the start of Ada time Res_Dur := Time_Dur (Res_N / Nano - Ada_Low / Nano); -- Count the number of days since the start of Ada time. 1901-1-1 -- GMT was a Tuesday. Day_Count := Long_Integer (Res_Dur / Secs_In_Day) + 1; return Integer (Day_Count mod 7); end Day_Of_Week; ----------- -- Split -- ----------- procedure Split (Date : Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Day_Secs : out Day_Duration; Hour : out Integer; Minute : out Integer; Second : out Integer; Sub_Sec : out Duration; Leap_Sec : out Boolean; Is_Ada_05 : Boolean; Time_Zone : Long_Integer) is -- The following constants represent the number of nanoseconds -- elapsed since the start of Ada time to and including the non -- leap centenial years. Year_2101 : constant Time_Rep := Ada_Low + Time_Rep (49 * 366 + 151 * 365) * Nanos_In_Day; Year_2201 : constant Time_Rep := Ada_Low + Time_Rep (73 * 366 + 227 * 365) * Nanos_In_Day; Year_2301 : constant Time_Rep := Ada_Low + Time_Rep (97 * 366 + 303 * 365) * Nanos_In_Day; Date_Dur : Time_Dur; Date_N : Time_Rep; Day_Seconds : Natural; Elapsed_Leaps : Natural; Four_Year_Segs : Natural; Hour_Seconds : Natural; Is_Leap_Year : Boolean; Next_Leap_N : Time_Rep; Rem_Years : Natural; Sub_Sec_N : Time_Rep; Year_Day : Natural; begin Date_N := Time_Rep (Date); -- Step 1: Leap seconds processing in UTC if Leap_Support then Cumulative_Leap_Seconds (Start_Of_Time, Date_N, Elapsed_Leaps, Next_Leap_N); Leap_Sec := Date_N >= Next_Leap_N; if Leap_Sec then Elapsed_Leaps := Elapsed_Leaps + 1; end if; -- The target does not support leap seconds else Elapsed_Leaps := 0; Leap_Sec := False; end if; Date_N := Date_N - Time_Rep (Elapsed_Leaps) * Nano; -- Step 2: Time zone processing. This action converts the input date -- from GMT to the requested time zone. if Is_Ada_05 then if Time_Zone /= 0 then Date_N := Date_N + Time_Rep (Time_Zone) * 60 * Nano; end if; -- Ada 83 and 95 else declare Off : constant Long_Integer := Time_Zones_Operations.UTC_Time_Offset (Time (Date_N)); begin Date_N := Date_N + Time_Rep (Off) * Nano; end; end if; -- Step 3: Non-leap centenial year adjustment in local time zone -- In order for all divisions to work properly and to avoid more -- complicated arithmetic, we add fake Febriary 29s to dates which -- occur after a non-leap centenial year. if Date_N >= Year_2301 then Date_N := Date_N + Time_Rep (3) * Nanos_In_Day; elsif Date_N >= Year_2201 then Date_N := Date_N + Time_Rep (2) * Nanos_In_Day; elsif Date_N >= Year_2101 then Date_N := Date_N + Time_Rep (1) * Nanos_In_Day; end if; -- Step 4: Sub second processing in local time zone Sub_Sec_N := Date_N mod Nano; Sub_Sec := Duration (Sub_Sec_N) / Nano_F; Date_N := Date_N - Sub_Sec_N; -- Convert Date_N into a time duration value, changing the units -- to seconds. Date_Dur := Time_Dur (Date_N / Nano - Ada_Low / Nano); -- Step 5: Year processing in local time zone. Determine the number -- of four year segments since the start of Ada time and the input -- date. Four_Year_Segs := Natural (Date_Dur / Secs_In_Four_Years); if Four_Year_Segs > 0 then Date_Dur := Date_Dur - Time_Dur (Four_Year_Segs) * Secs_In_Four_Years; end if; -- Calculate the remaining non-leap years Rem_Years := Natural (Date_Dur / Secs_In_Non_Leap_Year); if Rem_Years > 3 then Rem_Years := 3; end if; Date_Dur := Date_Dur - Time_Dur (Rem_Years) * Secs_In_Non_Leap_Year; Year := Ada_Min_Year + Natural (4 * Four_Year_Segs + Rem_Years); Is_Leap_Year := Is_Leap (Year); -- Step 6: Month and day processing in local time zone Year_Day := Natural (Date_Dur / Secs_In_Day) + 1; Month := 1; -- Processing for months after January if Year_Day > 31 then Month := 2; Year_Day := Year_Day - 31; -- Processing for a new month or a leap February if Year_Day > 28 and then (not Is_Leap_Year or else Year_Day > 29) then Month := 3; Year_Day := Year_Day - 28; if Is_Leap_Year then Year_Day := Year_Day - 1; end if; -- Remaining months while Year_Day > Days_In_Month (Month) loop Year_Day := Year_Day - Days_In_Month (Month); Month := Month + 1; end loop; end if; end if; -- Step 7: Hour, minute, second and sub second processing in local -- time zone. Day := Day_Number (Year_Day); Day_Seconds := Integer (Date_Dur mod Secs_In_Day); Day_Secs := Duration (Day_Seconds) + Sub_Sec; Hour := Day_Seconds / 3_600; Hour_Seconds := Day_Seconds mod 3_600; Minute := Hour_Seconds / 60; Second := Hour_Seconds mod 60; end Split; ------------- -- Time_Of -- ------------- function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Day_Secs : Day_Duration; Hour : Integer; Minute : Integer; Second : Integer; Sub_Sec : Duration; Leap_Sec : Boolean; Use_Day_Secs : Boolean; Is_Ada_05 : Boolean; Time_Zone : Long_Integer) return Time is Count : Integer; Elapsed_Leaps : Natural; Next_Leap_N : Time_Rep; Res_N : Time_Rep; Rounded_Res_N : Time_Rep; begin -- Step 1: Check whether the day, month and year form a valid date if Day > Days_In_Month (Month) and then (Day /= 29 or else Month /= 2 or else not Is_Leap (Year)) then raise Time_Error; end if; -- Start accumulating nanoseconds from the low bound of Ada time Res_N := Ada_Low; -- Step 2: Year processing and centenial year adjustment. Determine -- the number of four year segments since the start of Ada time and -- the input date. Count := (Year - Year_Number'First) / 4; Res_N := Res_N + Time_Rep (Count) * Secs_In_Four_Years * Nano; -- Note that non-leap centenial years are automatically considered -- leap in the operation above. An adjustment of several days is -- required to compensate for this. if Year > 2300 then Res_N := Res_N - Time_Rep (3) * Nanos_In_Day; elsif Year > 2200 then Res_N := Res_N - Time_Rep (2) * Nanos_In_Day; elsif Year > 2100 then Res_N := Res_N - Time_Rep (1) * Nanos_In_Day; end if; -- Add the remaining non-leap years Count := (Year - Year_Number'First) mod 4; Res_N := Res_N + Time_Rep (Count) * Secs_In_Non_Leap_Year * Nano; -- Step 3: Day of month processing. Determine the number of days -- since the start of the current year. Do not add the current -- day since it has not elapsed yet. Count := Cumulative_Days_Before_Month (Month) + Day - 1; -- The input year is leap and we have passed February if Is_Leap (Year) and then Month > 2 then Count := Count + 1; end if; Res_N := Res_N + Time_Rep (Count) * Nanos_In_Day; -- Step 4: Hour, minute, second and sub second processing if Use_Day_Secs then Res_N := Res_N + Duration_To_Time_Rep (Day_Secs); else Res_N := Res_N + Time_Rep (Hour * 3_600 + Minute * 60 + Second) * Nano; if Sub_Sec = 1.0 then Res_N := Res_N + Time_Rep (1) * Nano; else Res_N := Res_N + Duration_To_Time_Rep (Sub_Sec); end if; end if; -- At this point, the generated time value should be withing the -- bounds of Ada time. Check_Within_Time_Bounds (Res_N); -- Step 4: Time zone processing. At this point we have built an -- arbitrary time value which is not related to any time zone. -- For simplicity, the time value is normalized to GMT, producing -- a uniform representation which can be treated by arithmetic -- operations for instance without any additional corrections. if Is_Ada_05 then if Time_Zone /= 0 then Res_N := Res_N - Time_Rep (Time_Zone) * 60 * Nano; end if; -- Ada 83 and 95 else declare Current_Off : constant Long_Integer := Time_Zones_Operations.UTC_Time_Offset (Time (Res_N)); Current_Res_N : constant Time_Rep := Res_N - Time_Rep (Current_Off) * Nano; Off : constant Long_Integer := Time_Zones_Operations.UTC_Time_Offset (Time (Current_Res_N)); begin Res_N := Res_N - Time_Rep (Off) * Nano; end; end if; -- Step 5: Leap seconds processing in GMT if Leap_Support then Cumulative_Leap_Seconds (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N); Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano; -- An Ada 2005 caller requesting an explicit leap second or an -- Ada 95 caller accounting for an invisible leap second. if Leap_Sec or else Res_N >= Next_Leap_N then Res_N := Res_N + Time_Rep (1) * Nano; end if; -- Leap second validity check Rounded_Res_N := Res_N - (Res_N mod Nano); if Is_Ada_05 and then Leap_Sec and then Rounded_Res_N /= Next_Leap_N then raise Time_Error; end if; end if; return Time (Res_N); end Time_Of; end Formatting_Operations; --------------------------- -- Time_Zones_Operations -- --------------------------- package body Time_Zones_Operations is -- The Unix time bounds in nanoseconds: 1970/1/1 .. 2037/1/1 Unix_Min : constant Time_Rep := Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day; Unix_Max : constant Time_Rep := Ada_Low + Time_Rep (34 * 366 + 102 * 365) * Nanos_In_Day + Time_Rep (Leap_Seconds_Count) * Nano; -- The following constants denote February 28 during non-leap -- centenial years, the units are nanoseconds. T_2100_2_28 : constant Time_Rep := Ada_Low + (Time_Rep (49 * 366 + 150 * 365 + 59) * Secs_In_Day + Time_Rep (Leap_Seconds_Count)) * Nano; T_2200_2_28 : constant Time_Rep := Ada_Low + (Time_Rep (73 * 366 + 226 * 365 + 59) * Secs_In_Day + Time_Rep (Leap_Seconds_Count)) * Nano; T_2300_2_28 : constant Time_Rep := Ada_Low + (Time_Rep (97 * 366 + 302 * 365 + 59) * Secs_In_Day + Time_Rep (Leap_Seconds_Count)) * Nano; -- 56 years (14 leap years + 42 non leap years) in nanoseconds: Nanos_In_56_Years : constant := (14 * 366 + 42 * 365) * Nanos_In_Day; -- Base C types. There is no point dragging in Interfaces.C just for -- these four types. type char_Pointer is access Character; subtype int is Integer; subtype long is Long_Integer; type long_Pointer is access all long; -- The Ada equivalent of struct tm and type time_t type tm is record tm_sec : int; -- seconds after the minute (0 .. 60) tm_min : int; -- minutes after the hour (0 .. 59) tm_hour : int; -- hours since midnight (0 .. 24) tm_mday : int; -- day of the month (1 .. 31) tm_mon : int; -- months since January (0 .. 11) tm_year : int; -- years since 1900 tm_wday : int; -- days since Sunday (0 .. 6) tm_yday : int; -- days since January 1 (0 .. 365) tm_isdst : int; -- Daylight Savings Time flag (-1 .. 1) tm_gmtoff : long; -- offset from UTC in seconds tm_zone : char_Pointer; -- timezone abbreviation end record; type tm_Pointer is access all tm; subtype time_t is long; type time_t_Pointer is access all time_t; procedure localtime_tzoff (C : time_t_Pointer; res : tm_Pointer; off : long_Pointer); pragma Import (C, localtime_tzoff, "__gnat_localtime_tzoff"); -- This is a lightweight wrapper around the system library function -- localtime_r. Parameter 'off' captures the UTC offset which is either -- retrieved from the tm struct or calculated from the 'timezone' extern -- and the tm_isdst flag in the tm struct. --------------------- -- UTC_Time_Offset -- --------------------- function UTC_Time_Offset (Date : Time) return Long_Integer is Adj_Cent : Integer := 0; Date_N : Time_Rep; Offset : aliased long; Secs_T : aliased time_t; Secs_TM : aliased tm; begin Date_N := Time_Rep (Date); -- Dates which are 56 years appart fall on the same day, day light -- saving and so on. Non-leap centenial years violate this rule by -- one day and as a consequence, special adjustment is needed. if Date_N > T_2100_2_28 then if Date_N > T_2200_2_28 then if Date_N > T_2300_2_28 then Adj_Cent := 3; else Adj_Cent := 2; end if; else Adj_Cent := 1; end if; end if; if Adj_Cent > 0 then Date_N := Date_N - Time_Rep (Adj_Cent) * Nanos_In_Day; end if; -- Shift the date within bounds of Unix time while Date_N < Unix_Min loop Date_N := Date_N + Nanos_In_56_Years; end loop; while Date_N >= Unix_Max loop Date_N := Date_N - Nanos_In_56_Years; end loop; -- Perform a shift in origins from Ada to Unix Date_N := Date_N - Unix_Min; -- Convert the date into seconds Secs_T := time_t (Date_N / Nano); localtime_tzoff (Secs_T'Unchecked_Access, Secs_TM'Unchecked_Access, Offset'Unchecked_Access); return Offset; end UTC_Time_Offset; end Time_Zones_Operations; -- Start of elaboration code for Ada.Calendar begin System.OS_Primitives.Initialize; -- Population of the leap seconds table if Leap_Support then declare type Leap_Second_Date is record Year : Year_Number; Month : Month_Number; Day : Day_Number; end record; Leap_Second_Dates : constant array (1 .. Leap_Seconds_Count) of Leap_Second_Date := ((1972, 6, 30), (1972, 12, 31), (1973, 12, 31), (1974, 12, 31), (1975, 12, 31), (1976, 12, 31), (1977, 12, 31), (1978, 12, 31), (1979, 12, 31), (1981, 6, 30), (1982, 6, 30), (1983, 6, 30), (1985, 6, 30), (1987, 12, 31), (1989, 12, 31), (1990, 12, 31), (1992, 6, 30), (1993, 6, 30), (1994, 6, 30), (1995, 12, 31), (1997, 6, 30), (1998, 12, 31), (2005, 12, 31)); Days_In_Four_Years : constant := 365 * 3 + 366; Days : Natural; Leap : Leap_Second_Date; Years : Natural; begin for Index in 1 .. Leap_Seconds_Count loop Leap := Leap_Second_Dates (Index); -- Calculate the number of days from the start of Ada time until -- the current leap second occurence. Non-leap centenial years -- are not accounted for in these calculations since there are -- no leap seconds after 2100 yet. Years := Leap.Year - Ada_Min_Year; Days := (Years / 4) * Days_In_Four_Years; Years := Years mod 4; if Years = 1 then Days := Days + 365; elsif Years = 2 then Days := Days + 365 * 2; elsif Years = 3 then Days := Days + 365 * 3; end if; Days := Days + Cumulative_Days_Before_Month (Leap.Month); if Is_Leap (Leap.Year) and then Leap.Month > 2 then Days := Days + 1; end if; Days := Days + Leap.Day; -- Index - 1 previous leap seconds are added to Time (Index) as -- well as the lower buffer for time zones. Leap_Second_Times (Index) := Ada_Low + (Time_Rep (Days) * Secs_In_Day + Time_Rep (Index - 1)) * Nano; end loop; end; end if; end Ada.Calendar;