-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
+-- 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 2, or (at your option) any later ver- --
+-- 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. 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. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- 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. --
+-- 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;
--- used for Clock
package body Ada.Calendar is
--
-- 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 behing the design is to encapsulate all target
+ -- Ada.Calendar. The idea behind the design is to encapsulate all target
-- dependent machinery in a single package, thus providing a uniform
- -- interface to any existing and potential children.
+ -- interface to all existing and any potential children.
-- package Ada.Calendar
-- procedure Split (5 parameters) -------+
-- 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;
- End_Date : Time;
+ (Start_Date : Time_Rep;
+ End_Date : Time_Rep;
Elapsed_Leaps : out Natural;
- Next_Leap_Sec : out Time);
- -- Elapsed_Leaps is the sum of the leap seconds that have occured on or
+ 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 occurence on or after End_Date. If
- -- there are no leaps seconds after End_Date, After_Last_Leap is returned.
- -- After_Last_Leap can be used as End_Date to count all the leap seconds
- -- that have occured on or after Start_Date.
+ -- 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
-- 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 To_Abs_Duration (T : Time) return Duration;
- -- Convert a time value into a duration value. Note that the returned
- -- duration is always positive.
+ 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.
- function To_Abs_Time (D : Duration) return Time;
- -- Return the time equivalent of a duration value. Since time cannot be
- -- negative, the absolute value of D is used. It is upto the called to
- -- decide how to handle negative durations converted into time.
+ -----------------
+ -- 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;
- After_Last_Leap : constant Time := Time'Last;
- Leap_Seconds_Count : constant Natural := 23;
Secs_In_Four_Years : constant := (3 * 365 + 366) * Secs_In_Day;
Secs_In_Non_Leap_Year : constant := 365 * Secs_In_Day;
- Time_Zero : constant Time := Time'First;
+ 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;
- -- Even though the upper bound of Ada time is 2399-12-31 86_399.999999999
- -- GMT, it must be shifted to include all leap seconds.
+ -- The Unix lower time bound expressed as nanoseconds since the start of
+ -- Ada time in UTC.
- Ada_High_And_Leaps : constant Time :=
- Ada_High + Time (Leap_Seconds_Count) * Nano;
+ Unix_Min : constant Time_Rep :=
+ Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
- Hard_Ada_High_And_Leaps : constant Time :=
- Hard_Ada_High +
- Time (Leap_Seconds_Count) * Nano;
+ -- The Unix upper time bound expressed as nanoseconds since the start of
+ -- Ada time in UTC.
- -- The Unix lower time bound expressed as nanoseconds since the
- -- start of Ada time in GMT.
+ Unix_Max : constant Time_Rep :=
+ Ada_Low + Time_Rep (34 * 366 + 102 * 365) * Nanos_In_Day +
+ Time_Rep (Leap_Seconds_Count) * Nano;
- Unix_Min : constant Time := (17 * 366 + 52 * 365) * Nanos_In_Day;
+ 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);
- Leap_Second_Times : array (1 .. Leap_Seconds_Count) of Time;
- -- 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.
+ -- 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
- if Right = 0.0 then
- return Left;
-
- elsif Right < 0.0 then
-
- -- Type Duration has one additional number in its negative subrange,
- -- which is Duration'First. The subsequent invocation of "-" will
- -- perform among other things an Unchecked_Conversion on that
- -- particular value, causing overflow. If not properly handled,
- -- the erroneous value will cause an infinite recursion between "+"
- -- and "-". To properly handle this boundary case, we make a small
- -- adjustment of one second to Duration'First.
-
- if Right = Duration'First then
- return Left - abs (Right + 1.0) - 1.0;
- else
- return Left - abs (Right);
- end if;
-
- else
- declare
- -- The input time value has been normalized to GMT
-
- Result : constant Time := Left + To_Abs_Time (Right);
-
- begin
- -- The end result may excede the upper bound of Ada time. Note
- -- that the comparison operator is ">=" rather than ">" since
- -- the smallest increment of 0.000000001 to the legal end of
- -- time (2399-12-31 86_399.999999999) will render the result
- -- equal to Ada_High (2400-1-1 0.0).
-
- if Result >= Ada_High_And_Leaps then
- raise Time_Error;
- end if;
-
- return Result;
- end;
- end if;
-
+ return Time (Left_N + Duration_To_Time_Rep (Right));
exception
when Constraint_Error =>
raise Time_Error;
function "-" (Left : Time; Right : Duration) return Time is
pragma Unsuppress (Overflow_Check);
-
+ Left_N : constant Time_Rep := Time_Rep (Left);
begin
- if Right = 0.0 then
- return Left;
-
- elsif Right < 0.0 then
- return Left + abs (Right);
-
- else
- declare
- Result : Time;
- Right_T : constant Time := To_Abs_Time (Right);
-
- begin
- -- Subtracting a larger time value from a smaller time value
- -- will cause a wrap around since Time is a modular type. Note
- -- that the time value has been normalized to GMT.
-
- if Left < Right_T then
- raise Time_Error;
- end if;
-
- Result := Left - Right_T;
-
- if Result < Ada_Low
- or else Result > Ada_High_And_Leaps
- then
- raise Time_Error;
- end if;
-
- return Result;
- end;
- end if;
-
+ return Time (Left_N - Duration_To_Time_Rep (Right));
exception
when Constraint_Error =>
raise Time_Error;
function "-" (Left : Time; Right : Time) return Duration is
pragma Unsuppress (Overflow_Check);
- function To_Time is new Ada.Unchecked_Conversion (Duration, Time);
+ 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
- -- Since the absolute values of the upper and lower bound of duration
- -- are denoted by the same number, it is sufficend to use Duration'Last
- -- when performing out of range checks.
-
- Duration_Bound : constant Time := To_Time (Duration'Last);
-
- Earlier : Time;
- Later : Time;
- Negate : Boolean := False;
- Result : Time;
- Result_D : Duration;
+ Res_N : Time_Rep;
begin
- -- This routine becomes a little tricky since time cannot be negative,
- -- but the subtraction of two time values can produce a negative value.
-
- if Left > Right then
- Later := Left;
- Earlier := Right;
- else
- Later := Right;
- Earlier := Left;
- Negate := True;
- end if;
+ Res_N := Time_Rep (Left) - Time_Rep (Right);
- Result := Later - Earlier;
+ -- 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.
- -- Check whether the resulting difference is within the range of type
- -- Duration. The following two conditions are examined with the same
- -- piece of code:
- --
- -- positive result > positive upper bound of duration
- --
- -- negative (negative result) > abs (negative bound of duration)
-
- if Result > Duration_Bound then
+ if Res_N < Dur_Low or else Res_N > Dur_High then
raise Time_Error;
end if;
- Result_D := To_Abs_Duration (Result);
-
- if Negate then
- Result_D := -Result_D;
- end if;
+ return Time_Rep_To_Duration (Res_N);
- return Result_D;
exception
when Constraint_Error =>
raise Time_Error;
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 : Time;
-
- -- The system clock returns the time in GMT since the Unix Epoch of
- -- 1970-1-1 0.0. We perform an origin shift to the Ada Epoch by adding
- -- the number of nanoseconds between the two origins.
+ Next_Leap_N : Time_Rep;
- Now : Time := To_Abs_Time (System.OS_Primitives.Clock) + Unix_Min;
+ -- 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.
- Rounded_Now : constant Time := Now - (Now mod Nano);
+ Res_N : Time_Rep :=
+ Duration_To_Time_Rep (System.OS_Primitives.Clock) + Unix_Min;
begin
- -- Determine how many leap seconds have elapsed until this moment
+ -- If the target supports leap seconds, determine the number of leap
+ -- seconds elapsed until this moment.
- Cumulative_Leap_Seconds (Time_Zero, Now, Elapsed_Leaps, Next_Leap);
+ if Leap_Support then
+ Cumulative_Leap_Seconds
+ (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
- Now := Now + Time (Elapsed_Leaps) * Nano;
+ -- The system clock may fall exactly on a leap second
- -- The system clock may fall exactly on a leap second occurence
+ if Res_N >= Next_Leap_N then
+ Elapsed_Leaps := Elapsed_Leaps + 1;
+ end if;
- if Rounded_Now = Next_Leap then
- Now := Now + Time (1) * Nano;
+ -- The target does not support leap seconds
+
+ else
+ Elapsed_Leaps := 0;
end if;
- -- Add the buffer set aside for time zone processing since Split in
- -- Ada.Calendar.Formatting_Operations expects it to be there.
+ Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano;
- return Now + Buffer_N;
+ return Time (Res_N);
end Clock;
-----------------------------
-----------------------------
procedure Cumulative_Leap_Seconds
- (Start_Date : Time;
- End_Date : Time;
+ (Start_Date : Time_Rep;
+ End_Date : Time_Rep;
Elapsed_Leaps : out Natural;
- Next_Leap_Sec : out Time)
+ Next_Leap : out Time_Rep)
is
End_Index : Positive;
- End_T : Time := End_Date;
+ End_T : Time_Rep := End_Date;
Start_Index : Positive;
- Start_T : Time := Start_Date;
+ Start_T : Time_Rep := Start_Date;
begin
- -- Both input dates need to be normalized to GMT in order for this
- -- routine to work properly.
+ -- Both input dates must be normalized to UTC
- pragma Assert (End_Date >= Start_Date);
+ pragma Assert (Leap_Support and then End_Date >= Start_Date);
- Next_Leap_Sec := After_Last_Leap;
+ Next_Leap := End_Of_Time;
- -- Make sure that the end date does not excede the upper bound
+ -- Make sure that the end date does not exceed the upper bound
-- of Ada time.
if End_Date > Ada_High then
if End_T < Leap_Second_Times (1) then
Elapsed_Leaps := 0;
- Next_Leap_Sec := Leap_Second_Times (1);
+ Next_Leap := Leap_Second_Times (1);
return;
elsif Start_T > Leap_Second_Times (Leap_Seconds_Count) then
Elapsed_Leaps := 0;
- Next_Leap_Sec := After_Last_Leap;
+ Next_Leap := End_Of_Time;
return;
end if;
-- Perform the calculations only if the start date is within the leap
- -- second occurences table.
+ -- second occurrences table.
if Start_T <= Leap_Second_Times (Leap_Seconds_Count) then
end loop;
if End_Index <= Leap_Seconds_Count then
- Next_Leap_Sec := Leap_Second_Times (End_Index);
+ Next_Leap := Leap_Second_Times (End_Index);
end if;
Elapsed_Leaps := End_Index - Start_Index;
---------
function Day (Date : Time) return Day_Number is
+ D : Day_Number;
Y : Year_Number;
M : Month_Number;
- D : Day_Number;
S : Day_Duration;
+ pragma Unreferenced (Y, M, S);
begin
Split (Date, Y, M, D, S);
return D;
function Is_Leap (Year : Year_Number) return Boolean is
begin
- -- Leap centenial years
+ -- Leap centennial years
if Year mod 400 = 0 then
return True;
- -- Non-leap centenial years
+ -- Non-leap centennial years
elsif Year mod 100 = 0 then
return False;
M : Month_Number;
D : Day_Number;
S : Day_Duration;
+ pragma Unreferenced (Y, D, S);
begin
Split (Date, Y, M, D, S);
return M;
M : Month_Number;
D : Day_Number;
S : Day_Duration;
+ pragma Unreferenced (Y, M, D);
begin
Split (Date, Y, M, D, S);
return S;
Se : Integer;
Ss : Duration;
Le : Boolean;
- Tz : constant Long_Integer :=
- Time_Zones_Operations.UTC_Time_Offset (Date) / 60;
+
+ 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, Year, Month, Day, Seconds, H, M, Se, Ss, Le, Tz);
+ (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
+ 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;
Se : constant Integer := 1;
Ss : constant Duration := 0.1;
- Mid_Offset : Long_Integer;
- Mid_Result : Time;
- Offset : Long_Integer;
-
begin
- if not Year'Valid
- or else not Month'Valid
- or else not Day'Valid
- or else not Seconds'Valid
+ -- 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;
- -- Building a time value in a local time zone is tricky since the
- -- local time zone offset at the point of creation may not be the
- -- same as the actual time zone offset designated by the input
- -- values. The following example is relevant to New York, USA.
- --
- -- Creation date: 2006-10-10 0.0 Offset -240 mins (in DST)
- -- Actual date : 1901-01-01 0.0 Offset -300 mins (no DST)
+ -- 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;
- -- We first start by obtaining the current local time zone offset
- -- using Ada.Calendar.Clock, then building an intermediate time
- -- value using that offset.
+ ---------------------
+ -- UTC_Time_Offset --
+ ---------------------
- Mid_Offset := Time_Zones_Operations.UTC_Time_Offset (Clock) / 60;
- Mid_Result := Formatting_Operations.Time_Of
- (Year, Month, Day, Seconds, H, M, Se, Ss,
- Leap_Sec => False,
- Leap_Checks => False,
- Use_Day_Secs => True,
- Time_Zone => Mid_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.
- -- This is the true local time zone offset of the input time values
+ 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;
- Offset := Time_Zones_Operations.UTC_Time_Offset (Mid_Result) / 60;
+ 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;
- -- It is possible that at the point of invocation of Time_Of, both
- -- the current local time zone offset and the one designated by the
- -- input values are in the same DST mode.
+ 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;
- if Offset = Mid_Offset then
- return Mid_Result;
+ -- 56 years (14 leap years + 42 non-leap years) in nanoseconds:
- -- In this case we must calculate the new time with the new offset. It
- -- is no sufficient to just take the relative difference between the
- -- two offsets and adjust the intermediate result, because this does not
- -- work around leap second times.
+ Nanos_In_56_Years : constant := (14 * 366 + 42 * 365) * Nanos_In_Day;
- else
- declare
- Result : constant Time :=
- Formatting_Operations.Time_Of
- (Year, Month, Day, Seconds, H, M, Se, Ss,
- Leap_Sec => False,
- Leap_Checks => False,
- Use_Day_Secs => True,
- Time_Zone => Offset);
-
- begin
- return Result;
- end;
- end if;
- end Time_Of;
+ type int_Pointer is access all Interfaces.C.int;
+ type long_Pointer is access all Interfaces.C.long;
- ---------------------
- -- To_Abs_Duration --
- ---------------------
+ 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;
- function To_Abs_Duration (T : Time) return Duration is
- pragma Unsuppress (Overflow_Check);
- function To_Duration is new Ada.Unchecked_Conversion (Time, Duration);
+ 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
- return To_Duration (T);
+ Date_N := Time_Rep (Date);
- exception
- when Constraint_Error =>
- raise Time_Error;
- end To_Abs_Duration;
+ -- 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.
- -----------------
- -- To_Abs_Time --
- -----------------
+ 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);
- function To_Abs_Time (D : Duration) return Time is
- pragma Unsuppress (Overflow_Check);
- function To_Time is new Ada.Unchecked_Conversion (Duration, Time);
+ if Adj_Cent > 0 then
+ Date_N := Date_N - Time_Rep (Adj_Cent) * Nanos_In_Day;
+ end if;
- begin
- -- This operation assumes that D is positive
+ -- Shift the date within bounds of Unix time
- if D < 0.0 then
- raise Constraint_Error;
- end if;
+ while Date_N < Unix_Min loop
+ Date_N := Date_N + Nanos_In_56_Years;
+ end loop;
- return To_Time (D);
+ while Date_N >= Unix_Max loop
+ Date_N := Date_N - Nanos_In_56_Years;
+ end loop;
- exception
- when Constraint_Error =>
- raise Time_Error;
- end To_Abs_Time;
+ -- 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 --
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 modular 64 bit integer
+ -- 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 (1901-1-1 0.0).
+ -- time (1901-01-01 00:00:00.0 UTC).
---------------------------
-- Arithmetic_Operations --
---------
function Add (Date : Time; Days : Long_Integer) return Time is
+ pragma Unsuppress (Overflow_Check);
+ Date_N : constant Time_Rep := Time_Rep (Date);
begin
- if Days = 0 then
- return Date;
-
- elsif Days < 0 then
- return Subtract (Date, abs (Days));
-
- else
- declare
- Result : constant Time := Date + Time (Days) * Nanos_In_Day;
-
- begin
- -- The result excedes the upper bound of Ada time
-
- if Result > Ada_High_And_Leaps then
- raise Time_Error;
- end if;
-
- return Result;
- end;
- end if;
-
+ return Time (Date_N + Time_Rep (Days) * Nanos_In_Day);
exception
when Constraint_Error =>
raise Time_Error;
Seconds : out Duration;
Leap_Seconds : out Integer)
is
- Diff_N : Time;
- Diff_S : Time;
- Earlier : Time;
+ Res_Dur : Time_Dur;
+ Earlier : Time_Rep;
Elapsed_Leaps : Natural;
- Later : Time;
+ Later : Time_Rep;
Negate : Boolean := False;
- Next_Leap : Time;
- Sub_Seconds : Duration;
+ Next_Leap_N : Time_Rep;
+ Sub_Secs : Duration;
+ Sub_Secs_Diff : Time_Rep;
begin
- -- Both input time values are assumed to be in GMT
+ -- Both input time values are assumed to be in UTC
if Left >= Right then
- Later := Left;
- Earlier := Right;
+ Later := Time_Rep (Left);
+ Earlier := Time_Rep (Right);
else
- Later := Right;
- Earlier := Left;
+ Later := Time_Rep (Right);
+ Earlier := Time_Rep (Left);
Negate := True;
end if;
- -- First process the leap seconds
+ -- If the target supports leap seconds, process them
- Cumulative_Leap_Seconds (Earlier, Later, Elapsed_Leaps, Next_Leap);
+ if Leap_Support then
+ Cumulative_Leap_Seconds
+ (Earlier, Later, Elapsed_Leaps, Next_Leap_N);
- if Later >= Next_Leap then
- Elapsed_Leaps := Elapsed_Leaps + 1;
- end if;
+ if Later >= Next_Leap_N then
+ Elapsed_Leaps := Elapsed_Leaps + 1;
+ end if;
- Diff_N := Later - Earlier - Time (Elapsed_Leaps) * Nano;
+ -- The target does not support leap seconds
- -- Sub second processing
+ else
+ Elapsed_Leaps := 0;
+ end if;
- Sub_Seconds := Duration (Diff_N mod Nano) / Nano_F;
+ -- 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.
- -- Convert to seconds. Note that his action eliminates the sub
- -- seconds automatically.
+ Sub_Secs_Diff := Later mod Nano - Earlier mod Nano;
+ Earlier := Earlier + Sub_Secs_Diff;
+ Sub_Secs := Duration (Sub_Secs_Diff) / Nano_F;
- Diff_S := Diff_N / Nano;
+ -- 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.
- Days := Long_Integer (Diff_S / Secs_In_Day);
- Seconds := Duration (Diff_S mod Secs_In_Day) + Sub_Seconds;
+ 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;
- Leap_Seconds := -Leap_Seconds;
+ Days := -Days;
+ Seconds := -Seconds;
+
+ if Leap_Seconds /= 0 then
+ Leap_Seconds := -Leap_Seconds;
+ end if;
end if;
end Difference;
--------------
function Subtract (Date : Time; Days : Long_Integer) return Time is
+ pragma Unsuppress (Overflow_Check);
+ Date_N : constant Time_Rep := Time_Rep (Date);
begin
- if Days = 0 then
- return Date;
+ return Time (Date_N - Time_Rep (Days) * Nanos_In_Day);
+ exception
+ when Constraint_Error =>
+ raise Time_Error;
+ end Subtract;
- elsif Days < 0 then
- return Add (Date, abs (Days));
+ end Arithmetic_Operations;
- else
- declare
- Days_T : constant Time := Time (Days) * Nanos_In_Day;
- Result : Time;
+ ---------------------------
+ -- Conversion_Operations --
+ ---------------------------
- begin
- -- Subtracting a larger number of days from a smaller time
- -- value will cause wrap around since time is a modular type.
+ package body Conversion_Operations is
- if Date < Days_T then
- raise Time_Error;
- end if;
+ -----------------
+ -- To_Ada_Time --
+ -----------------
- Result := Date - Days_T;
+ 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;
- if Result < Ada_Low
- or else Result > Ada_High_And_Leaps
- then
- raise Time_Error;
- end if;
+ -----------------
+ -- To_Ada_Time --
+ -----------------
- return Result;
- end;
+ 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 Subtract;
- end Arithmetic_Operations;
+ 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 Delays_Operations is
+ package body Delay_Operations is
-----------------
-- To_Duration --
-----------------
- function To_Duration (Ada_Time : Time) return Duration is
+ 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;
- Modified_Time : Time;
- Next_Leap : Time;
- Result : Duration;
- Rounded_Time : Time;
+ Next_Leap_N : Time_Rep;
+ Res_N : Time_Rep;
begin
- Modified_Time := Ada_Time;
- Rounded_Time := Modified_Time - (Modified_Time mod Nano);
+ Res_N := Time_Rep (Date);
- -- Remove all leap seconds
+ -- Step 1: If the target supports leap seconds, remove any leap
+ -- seconds elapsed up to the input date.
- Cumulative_Leap_Seconds
- (Time_Zero, Modified_Time, Elapsed_Leaps, Next_Leap);
+ 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
- Modified_Time := Modified_Time - Time (Elapsed_Leaps) * Nano;
+ if Res_N >= Next_Leap_N then
+ Elapsed_Leaps := Elapsed_Leaps + 1;
+ end if;
- -- The input time value may fall on a leap second occurence
+ -- The target does not support leap seconds
- if Rounded_Time = Next_Leap then
- Modified_Time := Modified_Time - Time (1) * Nano;
+ else
+ Elapsed_Leaps := 0;
end if;
- -- Perform a shift in origins
+ Res_N := Res_N - Time_Rep (Elapsed_Leaps) * Nano;
- Result := Modified_Time - Unix_Min;
+ -- 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.
- -- Remove the buffer period used in time zone processing
+ Res_N := (if Res_N > Safe_Ada_High then Safe_Ada_High
+ else Res_N + Epoch_Offset);
- return Result - Buffer_D;
+ return Time_Rep_To_Duration (Res_N);
end To_Duration;
- end Delays_Operations;
+
+ end Delay_Operations;
---------------------------
-- Formatting_Operations --
-----------------
function Day_Of_Week (Date : Time) return Integer is
- Y : Year_Number;
- Mo : Month_Number;
- D : Day_Number;
- Dd : Day_Duration;
- H : Integer;
- Mi : Integer;
- Se : Integer;
- Su : Duration;
- Le : Boolean;
-
- Day_Count : Long_Integer;
- Midday_Date_S : Time;
+ 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
- Formatting_Operations.Split
- (Date, Y, Mo, D, Dd, H, Mi, Se, Su, Le, 0);
+ -- 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;
- -- Build a time value in the middle of the same day, remove the
- -- lower buffer and convert the time value to seconds.
+ 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;
- Midday_Date_S := (Formatting_Operations.Time_Of
- (Y, Mo, D, 0.0, 12, 0, 0, 0.0,
- Leap_Sec => False,
- Leap_Checks => False,
- Use_Day_Secs => False,
- Time_Zone => 0) - Buffer_N) / Nano;
+ -- Determine the elapsed seconds since the start of Ada time
- -- Count the number of days since the start of Ada time. 1901-1-1
+ 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 (Midday_Date_S / Secs_In_Day) + 1;
+ Day_Count := Long_Integer (Day_Dur / Secs_In_Day) + 1;
return Integer (Day_Count mod 7);
end Day_Of_Week;
-----------
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;
- Time_Zone : Long_Integer)
+ (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 := (49 * 366 + 151 * 365) * Nanos_In_Day;
- Year_2201 : constant Time := (73 * 366 + 227 * 365) * Nanos_In_Day;
- Year_2301 : constant Time := (97 * 366 + 303 * 365) * Nanos_In_Day;
-
- Abs_Time_Zone : Time;
- Day_Seconds : Natural;
- Elapsed_Leaps : Natural;
- Four_Year_Segs : Natural;
- Hour_Seconds : Natural;
- Is_Leap_Year : Boolean;
- Modified_Date_N : Time;
- Modified_Date_S : Time;
- Next_Leap_N : Time;
- Rem_Years : Natural;
- Rounded_Date_N : Time;
- Year_Day : Natural;
+ -- 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
- Modified_Date_N := Date;
+ Date_N := Time_Rep (Date);
- if Modified_Date_N < Hard_Ada_Low
- or else Modified_Date_N > Hard_Ada_High_And_Leaps
- then
- raise Time_Error;
- end if;
+ -- Step 1: Leap seconds processing in UTC
- -- Step 1: Leap seconds processing in GMT
-
- -- Day_Duration: 86_398 86_399 X (86_400) 0 (1) 1 (2)
- -- Time : --+-------+-------+----------+------+-->
- -- Seconds : 58 59 60 (Leap) 1 2
-
- -- o Modified_Date_N falls between 86_399 and X (86_400)
- -- Elapsed_Leaps = X - 1 leaps
- -- Rounded_Date_N = 86_399
- -- Next_Leap_N = X (86_400)
- -- Leap_Sec = False
-
- -- o Modified_Date_N falls exactly on X (86_400)
- -- Elapsed_Leaps = X - 1 leaps
- -- Rounded_Date_N = X (86_400)
- -- Next_Leap_N = X (86_400)
- -- Leap_Sec = True
- -- An invisible leap second will be added.
-
- -- o Modified_Date_N falls between X (86_400) and 0 (1)
- -- Elapsed_Leaps = X - 1 leaps
- -- Rounded_Date_N = X (86_400)
- -- Next_Leap_N = X (86_400)
- -- Leap_Sec = True
- -- An invisible leap second will be added.
-
- -- o Modified_Date_N falls on 0 (1)
- -- Elapsed_Leaps = X
- -- Rounded_Date_N = 0 (1)
- -- Next_Leap_N = X + 1
- -- Leap_Sec = False
- -- The invisible leap second has already been accounted for in
- -- Elapsed_Leaps.
+ if Leap_Support then
+ Cumulative_Leap_Seconds
+ (Start_Of_Time, Date_N, Elapsed_Leaps, Next_Leap_N);
- Cumulative_Leap_Seconds
- (Time_Zero, Modified_Date_N, Elapsed_Leaps, Next_Leap_N);
+ Leap_Sec := Date_N >= Next_Leap_N;
- Rounded_Date_N := Modified_Date_N - (Modified_Date_N mod Nano);
- Leap_Sec := Rounded_Date_N = Next_Leap_N;
- Modified_Date_N := Modified_Date_N - Time (Elapsed_Leaps) * Nano;
+ if Leap_Sec then
+ Elapsed_Leaps := Elapsed_Leaps + 1;
+ end if;
- if Leap_Sec then
- Modified_Date_N := Modified_Date_N - Time (1) * Nano;
- end if;
+ -- The target does not support leap seconds
- -- Step 2: Time zone processing. This action converts the input date
- -- from GMT to the requested time zone.
+ else
+ Elapsed_Leaps := 0;
+ Leap_Sec := False;
+ end if;
- if Time_Zone /= 0 then
- Abs_Time_Zone := Time (abs (Time_Zone)) * 60 * Nano;
+ Date_N := Date_N - Time_Rep (Elapsed_Leaps) * Nano;
- if Time_Zone < 0 then
- -- The following test is obsolete since the date already
- -- contains the dedicated buffer for time zones, thus no
- -- error will be raised. However it is a good idea to keep
- -- it should the representation of time change.
+ -- Step 2: Time zone processing. This action converts the input date
+ -- from GMT to the requested time zone. Applies from Ada 2005 on.
- Modified_Date_N := Modified_Date_N - Abs_Time_Zone;
- else
- Modified_Date_N := Modified_Date_N + Abs_Time_Zone;
+ if Is_Ada_05 then
+ if Time_Zone /= 0 then
+ Date_N := Date_N + Time_Rep (Time_Zone) * 60 * Nano;
end if;
- end if;
- -- After the elapsed leap seconds have been removed and the date
- -- has been normalized, it should fall withing the soft bounds of
- -- Ada time.
+ -- Ada 83 and 95
- if Modified_Date_N < Ada_Low
- or else Modified_Date_N > Ada_High
- then
- raise Time_Error;
- end if;
-
- -- Before any additional arithmetic is performed we must remove the
- -- lower buffer period since it will be accounted as few additional
- -- days.
+ else
+ declare
+ Off : constant Long_Integer :=
+ UTC_Time_Offset (Time (Date_N), False);
- Modified_Date_N := Modified_Date_N - Buffer_N;
+ begin
+ Date_N := Date_N + Time_Rep (Off) * Nano;
+ end;
+ end if;
- -- Step 3: Non-leap centenial year adjustment in local time zone
+ -- 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 Febriary 29s to dates which
- -- occur after a non-leap centenial year.
+ -- complicated arithmetic, we add fake February 29s to dates which
+ -- occur after a non-leap centennial year.
- if Modified_Date_N >= Year_2301 then
- Modified_Date_N := Modified_Date_N + Time (3) * Nanos_In_Day;
+ if Date_N >= Year_2301 then
+ Date_N := Date_N + Time_Rep (3) * Nanos_In_Day;
- elsif Modified_Date_N >= Year_2201 then
- Modified_Date_N := Modified_Date_N + Time (2) * Nanos_In_Day;
+ elsif Date_N >= Year_2201 then
+ Date_N := Date_N + Time_Rep (2) * Nanos_In_Day;
- elsif Modified_Date_N >= Year_2101 then
- Modified_Date_N := Modified_Date_N + Time (1) * 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 := Duration (Modified_Date_N mod Nano) / Nano_F;
+ Sub_Sec_N := Date_N mod Nano;
+ Sub_Sec := Duration (Sub_Sec_N) / Nano_F;
+ Date_N := Date_N - Sub_Sec_N;
- -- Convert the date into seconds, the sub seconds are automatically
- -- dropped.
+ -- Convert Date_N into a time duration value, changing the units
+ -- to seconds.
- Modified_Date_S := Modified_Date_N / Nano;
+ 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 (Modified_Date_S / Secs_In_Four_Years);
+ Four_Year_Segs := Natural (Date_Dur / Secs_In_Four_Years);
if Four_Year_Segs > 0 then
- Modified_Date_S := Modified_Date_S - Time (Four_Year_Segs) *
- Secs_In_Four_Years;
+ Date_Dur := Date_Dur - Time_Dur (Four_Year_Segs) *
+ Secs_In_Four_Years;
end if;
-- Calculate the remaining non-leap years
- Rem_Years := Natural (Modified_Date_S / Secs_In_Non_Leap_Year);
+ Rem_Years := Natural (Date_Dur / Secs_In_Non_Leap_Year);
if Rem_Years > 3 then
Rem_Years := 3;
end if;
- Modified_Date_S := Modified_Date_S - Time (Rem_Years) *
- Secs_In_Non_Leap_Year;
+ 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 (Modified_Date_S / Secs_In_Day) + 1;
+ Year_Day := Natural (Date_Dur / Secs_In_Day) + 1;
Month := 1;
-- Processing for a new month or a leap February
if Year_Day > 28
- and then (not Is_Leap_Year
- or else Year_Day > 29)
+ and then (not Is_Leap_Year or else Year_Day > 29)
then
Month := 3;
Year_Day := Year_Day - 28;
-- time zone.
Day := Day_Number (Year_Day);
- Day_Seconds := Integer (Modified_Date_S mod Secs_In_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 : Integer;
Second : Integer;
Sub_Sec : Duration;
- Leap_Sec : Boolean;
- Leap_Checks : Boolean;
- Use_Day_Secs : Boolean;
- Time_Zone : Long_Integer) return Time
+ Leap_Sec : Boolean := False;
+ Use_Day_Secs : Boolean := False;
+ Is_Ada_05 : Boolean := False;
+ Time_Zone : Long_Integer := 0) return Time
is
- Abs_Time_Zone : Time;
- Count : Integer;
- Elapsed_Leaps : Natural;
- Next_Leap_N : Time;
- Result_N : Time;
- Rounded_Result_N : Time;
+ 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
raise Time_Error;
end if;
- -- Start accumulating nanoseconds from the low bound of Ada time.
- -- Note: This starting point includes the lower buffer dedicated
- -- to time zones.
+ -- Start accumulating nanoseconds from the low bound of Ada time
- Result_N := Ada_Low;
+ Res_N := Ada_Low;
- -- Step 2: Year processing and centenial year adjustment. Determine
+ -- 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;
- Result_N := Result_N + Time (Count) * Secs_In_Four_Years * Nano;
+ Count := (Year - Year_Number'First) / 4;
- -- Note that non-leap centenial years are automatically considered
+ 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
- Result_N := Result_N - Time (3) * Nanos_In_Day;
+ Res_N := Res_N - Time_Rep (3) * Nanos_In_Day;
elsif Year > 2200 then
- Result_N := Result_N - Time (2) * Nanos_In_Day;
+ Res_N := Res_N - Time_Rep (2) * Nanos_In_Day;
elsif Year > 2100 then
- Result_N := Result_N - Time (1) * Nanos_In_Day;
+ 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;
- Result_N := Result_N + Time (Count) * Secs_In_Non_Leap_Year * Nano;
+ 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
Count := Count + 1;
end if;
- Result_N := Result_N + Time (Count) * Nanos_In_Day;
+ Res_N := Res_N + Time_Rep (Count) * Nanos_In_Day;
-- Step 4: Hour, minute, second and sub second processing
if Use_Day_Secs then
- Result_N := Result_N + To_Abs_Time (Day_Secs);
+ Res_N := Res_N + Duration_To_Time_Rep (Day_Secs);
else
- Result_N := Result_N +
- Time (Hour * 3_600 + Minute * 60 + Second) * Nano;
+ Res_N :=
+ Res_N + Time_Rep (Hour * 3_600 + Minute * 60 + Second) * Nano;
if Sub_Sec = 1.0 then
- Result_N := Result_N + Time (1) * Nano;
+ Res_N := Res_N + Time_Rep (1) * Nano;
else
- Result_N := Result_N + To_Abs_Time (Sub_Sec);
+ 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 Result_N < Ada_Low
- or else Result_N > Ada_High
- then
- raise Time_Error;
- end if;
-
- if Time_Zone /= 0 then
- Abs_Time_Zone := Time (abs (Time_Zone)) * 60 * Nano;
+ if Is_Ada_05 then
+ if Time_Zone /= 0 then
+ Res_N := Res_N - Time_Rep (Time_Zone) * 60 * Nano;
+ end if;
- if Time_Zone < 0 then
- Result_N := Result_N + Abs_Time_Zone;
- else
- -- The following test is obsolete since the result already
- -- contains the dedicated buffer for time zones, thus no
- -- error will be raised. However it is a good idea to keep
- -- this comparison should the representation of time change.
+ -- Ada 83 and 95
- if Result_N < Abs_Time_Zone then
- raise Time_Error;
- end if;
+ 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);
- Result_N := Result_N - Abs_Time_Zone;
- end if;
+ begin
+ Res_N := Res_N - Time_Rep (Off) * Nano;
+ end;
end if;
-- Step 5: Leap seconds processing in GMT
- Cumulative_Leap_Seconds
- (Time_Zero, Result_N, Elapsed_Leaps, Next_Leap_N);
+ if Leap_Support then
+ Cumulative_Leap_Seconds
+ (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
- Result_N := Result_N + Time (Elapsed_Leaps) * Nano;
+ 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.
+ -- An Ada 2005 caller requesting an explicit leap second or an
+ -- Ada 95 caller accounting for an invisible leap second.
- Rounded_Result_N := Result_N - (Result_N mod Nano);
-
- if Leap_Sec
- or else Rounded_Result_N = Next_Leap_N
- then
- Result_N := Result_N + Time (1) * Nano;
- Rounded_Result_N := Rounded_Result_N + Time (1) * Nano;
- end if;
-
- -- Leap second validity check
+ if Leap_Sec or else Res_N >= Next_Leap_N then
+ Res_N := Res_N + Time_Rep (1) * Nano;
+ end if;
- if Leap_Checks
- and then Leap_Sec
- and then Rounded_Result_N /= Next_Leap_N
- then
- raise Time_Error;
- end if;
+ -- Leap second validity check
- -- Final bounds check
+ Rounded_Res_N := Res_N - (Res_N mod Nano);
- if Result_N < Hard_Ada_Low
- or else Result_N > Hard_Ada_High_And_Leaps
- then
- raise Time_Error;
+ 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 Result_N;
+ return Time (Res_N);
end Time_Of;
+
end Formatting_Operations;
---------------------------
package body Time_Zones_Operations is
- -- The Unix time bounds in seconds: 1970/1/1 .. 2037/1/1
-
- Unix_Min : constant Time :=
- Time (17 * 366 + 52 * 365 + 2) * Secs_In_Day;
- -- 1970/1/1
-
- Unix_Max : constant Time :=
- Time (34 * 366 + 102 * 365 + 2) * Secs_In_Day +
- Time (Leap_Seconds_Count);
- -- 2037/1/1
-
- -- The following constants denote February 28 during non-leap
- -- centenial years, the units are nanoseconds.
-
- T_2100_2_28 : constant Time :=
- (Time (49 * 366 + 150 * 365 + 59 + 2) * Secs_In_Day +
- Time (Leap_Seconds_Count)) * Nano;
-
- T_2200_2_28 : constant Time :=
- (Time (73 * 366 + 226 * 365 + 59 + 2) * Secs_In_Day +
- Time (Leap_Seconds_Count)) * Nano;
-
- T_2300_2_28 : constant Time :=
- (Time (97 * 366 + 302 * 365 + 59 + 2) * Secs_In_Day +
- Time (Leap_Seconds_Count)) * Nano;
-
- -- 56 years (14 leap years + 42 non leap years) in seconds:
-
- Secs_In_56_Years : constant := (14 * 366 + 42 * 365) * Secs_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;
- Adj_Date_N : Time;
- Adj_Date_S : Time;
- Offset : aliased long;
- Secs_T : aliased time_t;
- Secs_TM : aliased tm;
-
begin
- Adj_Date_N := 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 Adj_Date_N > T_2100_2_28 then
- if Adj_Date_N > T_2200_2_28 then
- if Adj_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
- Adj_Date_N := Adj_Date_N - Time (Adj_Cent) * Nanos_In_Day;
- end if;
-
- -- Convert to seconds and shift date within bounds of Unix time
-
- Adj_Date_S := Adj_Date_N / Nano;
- while Adj_Date_S < Unix_Min loop
- Adj_Date_S := Adj_Date_S + Secs_In_56_Years;
- end loop;
-
- while Adj_Date_S >= Unix_Max loop
- Adj_Date_S := Adj_Date_S - Secs_In_56_Years;
- end loop;
-
- -- Perform a shift in origins from Ada to Unix
-
- Adj_Date_S := Adj_Date_S - Unix_Min;
-
- Secs_T := time_t (Adj_Date_S);
-
- localtime_tzoff
- (Secs_T'Unchecked_Access,
- Secs_TM'Unchecked_Access,
- Offset'Unchecked_Access);
-
- return Offset;
+ 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;
- -- Population of the leap seconds table
-
- 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 (Days) * Secs_In_Day + Time (Index - 1)) * Nano;
- end loop;
- end;
-
end Ada.Calendar;
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