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------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- A D A . C A L E N D A R -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2012, 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 3, 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. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- <http://www.gnu.org/licenses/>. -- -- -- -- 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 Interfaces.C; with System.OS_Primitives; 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 occurred on or -- after Start_Date and before (strictly before) End_Date. Next_Leap_Sec -- represents the next leap second occurrence 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 occurred 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 function UTC_Time_Offset (Date : Time; Is_Historic : Boolean) return Long_Integer; -- This routine acts as an Ada wrapper around __gnat_localtime_tzoff which -- in turn utilizes various OS-dependent mechanisms to calculate the time -- zone offset of a date. Formal parameter Date represents an arbitrary -- time stamp, either in the past, now, or in the future. If the flag -- Is_Historic is set, this routine would try to calculate to the best of -- the OS's abilities the time zone offset that was or will be in effect -- on Date. If the flag is set to False, the routine returns the current -- time zone with Date effectively set to Clock. -- -- NOTE: Targets which support localtime_r will aways return a historic -- time zone even if flag Is_Historic is set to False because this is how -- localtime_r operates. ----------------- -- 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; -------------------------- -- Leap seconds control -- -------------------------- Flag : Integer; pragma Import (C, Flag, "__gl_leap_seconds_support"); -- This imported value is used to determine whether the compilation had -- binder flag "-y" present which enables leap seconds. A value of zero -- signifies no leap seconds support while a value of one enables support. Leap_Support : constant Boolean := (Flag = 1); -- Flag to controls the usage of leap seconds in all Ada.Calendar routines Leap_Seconds_Count : constant Natural := 25; --------------------- -- Local Constants -- --------------------- 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; Nanos_In_Four_Years : constant := Secs_In_Four_Years * Nano; -- 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 centennial 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; -- The Unix upper time bound expressed as nanoseconds since the start of -- Ada time in UTC. Unix_Max : constant Time_Rep := Ada_Low + Time_Rep (34 * 366 + 102 * 365) * Nanos_In_Day + Time_Rep (Leap_Seconds_Count) * Nano; Epoch_Offset : constant Time_Rep := (136 * 365 + 44 * 366) * Nanos_In_Day; -- The difference between 2150-1-1 UTC and 1970-1-1 UTC expressed in -- nanoseconds. Note that year 2100 is non-leap. Cumulative_Days_Before_Month : constant array (Month_Number) of Natural := (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334); -- The following table contains the hard time values of all existing leap -- seconds. The values are produced by the utility program xleaps.adb. This -- must be updated when additional leap second times are defined. Leap_Second_Times : constant array (1 .. Leap_Seconds_Count) of Time_Rep := (-5601484800000000000, -5585587199000000000, -5554051198000000000, -5522515197000000000, -5490979196000000000, -5459356795000000000, -5427820794000000000, -5396284793000000000, -5364748792000000000, -5317487991000000000, -5285951990000000000, -5254415989000000000, -5191257588000000000, -5112287987000000000, -5049129586000000000, -5017593585000000000, -4970332784000000000, -4938796783000000000, -4907260782000000000, -4859827181000000000, -4812566380000000000, -4765132779000000000, -4544207978000000000, -4449513577000000000, -4339180776000000000); --------- -- "+" -- --------- function "+" (Left : Time; Right : Duration) return Time is pragma Unsuppress (Overflow_Check); Left_N : constant Time_Rep := Time_Rep (Left); begin return Time (Left_N + Duration_To_Time_Rep (Right)); 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); begin return Time (Left_N - Duration_To_Time_Rep (Right)); exception when Constraint_Error => raise Time_Error; end "-"; function "-" (Left : Time; Right : Time) return Duration is pragma Unsuppress (Overflow_Check); Dur_Low : constant Time_Rep := Duration_To_Time_Rep (Duration'First); Dur_High : constant Time_Rep := Duration_To_Time_Rep (Duration'Last); -- The bounds of type Duration expressed as time representations Res_N : Time_Rep; begin Res_N := Time_Rep (Left) - Time_Rep (Right); -- Due to the extended range of Ada time, "-" is capable of producing -- results which may exceed the range of Duration. In order to prevent -- the generation of bogus values by the Unchecked_Conversion, we apply -- the following check. 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 exceed 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 occurrences 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 D : Day_Number; Y : Year_Number; M : Month_Number; S : Day_Duration; pragma Unreferenced (Y, M, S); begin Split (Date, Y, M, D, S); return D; end Day; ------------- -- Is_Leap -- ------------- function Is_Leap (Year : Year_Number) return Boolean is begin -- Leap centennial years if Year mod 400 = 0 then return True; -- Non-leap centennial 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; pragma Unreferenced (Y, D, S); 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; pragma Unreferenced (Y, M, D); 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; pragma Unreferenced (H, M, Se, Ss, Le); 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; --------------------- -- UTC_Time_Offset -- --------------------- function UTC_Time_Offset (Date : Time; Is_Historic : Boolean) return Long_Integer is -- The following constants denote February 28 during non-leap centennial -- 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; type int_Pointer is access all Interfaces.C.int; type long_Pointer is access all Interfaces.C.long; type time_t is range -(2 ** (Standard'Address_Size - Integer'(1))) .. +(2 ** (Standard'Address_Size - Integer'(1)) - 1); type time_t_Pointer is access all time_t; procedure localtime_tzoff (timer : time_t_Pointer; is_historic : int_Pointer; off : long_Pointer); pragma Import (C, localtime_tzoff, "__gnat_localtime_tzoff"); -- This routine is a interfacing wrapper around the library function -- __gnat_localtime_tzoff. Parameter 'timer' represents a Unix-based -- time equivalent of the input date. If flag 'is_historic' is set, this -- routine would try to calculate to the best of the OS's abilities the -- time zone offset that was or will be in effect on 'timer'. If the -- flag is set to False, the routine returns the current time zone -- regardless of what 'timer' designates. Parameter 'off' captures the -- UTC offset of 'timer'. Adj_Cent : Integer; Date_N : Time_Rep; Flag : aliased Interfaces.C.int; Offset : aliased Interfaces.C.long; Secs_T : aliased time_t; -- Start of processing for UTC_Time_Offset begin Date_N := Time_Rep (Date); -- Dates which are 56 years apart fall on the same day, day light saving -- and so on. Non-leap centennial years violate this rule by one day and -- as a consequence, special adjustment is needed. Adj_Cent := (if Date_N <= T_2100_2_28 then 0 elsif Date_N <= T_2200_2_28 then 1 elsif Date_N <= T_2300_2_28 then 2 else 3); 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); -- Determine whether to treat the input date as historical or not Flag := (if Is_Historic then 1 else 0); localtime_tzoff (Secs_T'Unchecked_Access, Flag'Unchecked_Access, Offset'Unchecked_Access); return Long_Integer (Offset); end UTC_Time_Offset; ---------- -- Year -- ---------- function Year (Date : Time) return Year_Number is Y : Year_Number; M : Month_Number; D : Day_Number; S : Day_Duration; pragma Unreferenced (M, D, S); 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); begin return Time (Date_N + Time_Rep (Days) * Nanos_In_Day); 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; Elapsed_Leaps : Natural; Later : Time_Rep; Negate : Boolean := False; Next_Leap_N : Time_Rep; Sub_Secs : Duration; Sub_Secs_Diff : Time_Rep; 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 processing. We add the resulting difference to one -- of the input dates in order to account for any potential rounding -- of the difference in the next step. Sub_Secs_Diff := Later mod Nano - Earlier mod Nano; Earlier := Earlier + Sub_Secs_Diff; Sub_Secs := Duration (Sub_Secs_Diff) / Nano_F; -- Difference processing. This operation should be able to calculate -- the difference between opposite values which are close to the end -- and start of Ada time. To accommodate the large range, we convert -- to seconds. This action may potentially round the two values and -- either add or drop a second. We compensate for this issue in the -- previous step. 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_Secs; 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); begin return Time (Date_N - Time_Rep (Days) * Nanos_In_Day); exception when Constraint_Error => raise Time_Error; end Subtract; end Arithmetic_Operations; --------------------------- -- Conversion_Operations -- --------------------------- package body Conversion_Operations is ----------------- -- To_Ada_Time -- ----------------- function To_Ada_Time (Unix_Time : Long_Integer) return Time is pragma Unsuppress (Overflow_Check); Unix_Rep : constant Time_Rep := Time_Rep (Unix_Time) * Nano; begin return Time (Unix_Rep - Epoch_Offset); exception when Constraint_Error => raise Time_Error; end To_Ada_Time; ----------------- -- To_Ada_Time -- ----------------- function To_Ada_Time (tm_year : Integer; tm_mon : Integer; tm_day : Integer; tm_hour : Integer; tm_min : Integer; tm_sec : Integer; tm_isdst : Integer) return Time is pragma Unsuppress (Overflow_Check); Year : Year_Number; Month : Month_Number; Day : Day_Number; Second : Integer; Leap : Boolean; Result : Time_Rep; begin -- Input processing Year := Year_Number (1900 + tm_year); Month := Month_Number (1 + tm_mon); Day := Day_Number (tm_day); -- Step 1: Validity checks of input values if not Year'Valid or else not Month'Valid or else not Day'Valid or else tm_hour not in 0 .. 24 or else tm_min not in 0 .. 59 or else tm_sec not in 0 .. 60 or else tm_isdst not in -1 .. 1 then raise Time_Error; end if; -- Step 2: Potential leap second if tm_sec = 60 then Leap := True; Second := 59; else Leap := False; Second := tm_sec; end if; -- Step 3: Calculate the time value Result := Time_Rep (Formatting_Operations.Time_Of (Year => Year, Month => Month, Day => Day, Day_Secs => 0.0, -- Time is given in h:m:s Hour => tm_hour, Minute => tm_min, Second => Second, Sub_Sec => 0.0, -- No precise sub second given Leap_Sec => Leap, Use_Day_Secs => False, -- Time is given in h:m:s Is_Ada_05 => True, -- Force usage of explicit time zone Time_Zone => 0)); -- Place the value in UTC -- Step 4: Daylight Savings Time if tm_isdst = 1 then Result := Result + Time_Rep (3_600) * Nano; end if; return Time (Result); exception when Constraint_Error => raise Time_Error; end To_Ada_Time; ----------------- -- To_Duration -- ----------------- function To_Duration (tv_sec : Long_Integer; tv_nsec : Long_Integer) return Duration is pragma Unsuppress (Overflow_Check); begin return Duration (tv_sec) + Duration (tv_nsec) / Nano_F; end To_Duration; ------------------------ -- To_Struct_Timespec -- ------------------------ procedure To_Struct_Timespec (D : Duration; tv_sec : out Long_Integer; tv_nsec : out Long_Integer) is pragma Unsuppress (Overflow_Check); Secs : Duration; Nano_Secs : Duration; begin -- Seconds extraction, avoid potential rounding errors Secs := D - 0.5; tv_sec := Long_Integer (Secs); -- Nanoseconds extraction Nano_Secs := D - Duration (tv_sec); tv_nsec := Long_Integer (Nano_Secs * Nano); end To_Struct_Timespec; ------------------ -- To_Struct_Tm -- ------------------ procedure To_Struct_Tm (T : Time; tm_year : out Integer; tm_mon : out Integer; tm_day : out Integer; tm_hour : out Integer; tm_min : out Integer; tm_sec : out Integer) is pragma Unsuppress (Overflow_Check); Year : Year_Number; Month : Month_Number; Second : Integer; Day_Secs : Day_Duration; Sub_Sec : Duration; Leap_Sec : Boolean; begin -- Step 1: Split the input time Formatting_Operations.Split (T, Year, Month, tm_day, Day_Secs, tm_hour, tm_min, Second, Sub_Sec, Leap_Sec, True, 0); -- Step 2: Correct the year and month tm_year := Year - 1900; tm_mon := Month - 1; -- Step 3: Handle leap second occurrences tm_sec := (if Leap_Sec then 60 else Second); end To_Struct_Tm; ------------------ -- To_Unix_Time -- ------------------ function To_Unix_Time (Ada_Time : Time) return Long_Integer is pragma Unsuppress (Overflow_Check); Ada_Rep : constant Time_Rep := Time_Rep (Ada_Time); begin return Long_Integer ((Ada_Rep + Epoch_Offset) / Nano); exception when Constraint_Error => raise Time_Error; end To_Unix_Time; end Conversion_Operations; ---------------------- -- Delay_Operations -- ---------------------- package body Delay_Operations is ----------------- -- To_Duration -- ----------------- function To_Duration (Date : Time) return Duration is pragma Unsuppress (Overflow_Check); Safe_Ada_High : constant Time_Rep := Ada_High - Epoch_Offset; -- This value represents a "safe" end of time. In order to perform a -- proper conversion to Unix duration, we will have to shift origins -- at one point. For very distant dates, this means an overflow check -- failure. To prevent this, the function returns the "safe" end of -- time (roughly 2219) which is still distant enough. Elapsed_Leaps : Natural; Next_Leap_N : Time_Rep; Res_N : Time_Rep; begin Res_N := Time_Rep (Date); -- Step 1: If the target supports leap seconds, remove any leap -- seconds elapsed up to 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 occurrence 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; -- Step 2: Perform a shift in origins to obtain a Unix equivalent of -- the input. Guard against very large delay values such as the end -- of time since the computation will overflow. Res_N := (if Res_N > Safe_Ada_High then Safe_Ada_High else Res_N + Epoch_Offset); return Time_Rep_To_Duration (Res_N); end To_Duration; end Delay_Operations; --------------------------- -- Formatting_Operations -- --------------------------- package body Formatting_Operations is ----------------- -- Day_Of_Week -- ----------------- function Day_Of_Week (Date : Time) return Integer is Date_N : constant Time_Rep := Time_Rep (Date); Time_Zone : constant Long_Integer := UTC_Time_Offset (Date, True); Ada_Low_N : Time_Rep; Day_Count : Long_Integer; Day_Dur : Time_Dur; High_N : Time_Rep; Low_N : Time_Rep; begin -- As declared, the Ada Epoch is set in UTC. For this calculation to -- work properly, both the Epoch and the input date must be in the -- same time zone. The following places the Epoch in the input date's -- time zone. Ada_Low_N := Ada_Low - Time_Rep (Time_Zone) * Nano; if Date_N > Ada_Low_N then High_N := Date_N; Low_N := Ada_Low_N; else High_N := Ada_Low_N; Low_N := Date_N; end if; -- Determine the elapsed seconds since the start of Ada time Day_Dur := Time_Dur (High_N / Nano - Low_N / Nano); -- Count the number of days since the start of Ada time. 1901-01-01 -- GMT was a Tuesday. Day_Count := Long_Integer (Day_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 centennial 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. Applies from Ada 2005 on. 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 := UTC_Time_Offset (Time (Date_N), False); begin Date_N := Date_N + Time_Rep (Off) * Nano; end; end if; -- Step 3: Non-leap centennial year adjustment in local time zone -- In order for all divisions to work properly and to avoid more -- complicated arithmetic, we add fake February 29s to dates which -- occur after a non-leap centennial 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 := False; Use_Day_Secs : Boolean := False; Is_Ada_05 : Boolean := False; Time_Zone : Long_Integer := 0) 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 centennial 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; for Four_Year_Segments in 1 .. Count loop Res_N := Res_N + Nanos_In_Four_Years; end loop; -- Note that non-leap centennial 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 := UTC_Time_Offset (Time (Res_N), False); Current_Res_N : constant Time_Rep := Res_N - Time_Rep (Current_Off) * Nano; Off : constant Long_Integer := UTC_Time_Offset (Time (Current_Res_N), False); 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 --------------------- -- UTC_Time_Offset -- --------------------- function UTC_Time_Offset (Date : Time) return Long_Integer is begin return UTC_Time_Offset (Date, True); end UTC_Time_Offset; end Time_Zones_Operations; -- Start of elaboration code for Ada.Calendar begin System.OS_Primitives.Initialize; end Ada.Calendar;
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