1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . C A L E N D A R --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 with Ada.Unchecked_Conversion;
34 with System.OS_Primitives;
36 package body Ada.Calendar is
38 --------------------------
39 -- Implementation Notes --
40 --------------------------
42 -- In complex algorithms, some variables of type Ada.Calendar.Time carry
43 -- suffix _S or _N to denote units of seconds or nanoseconds.
45 -- Because time is measured in different units and from different origins
46 -- on various targets, a system independent model is incorporated into
47 -- Ada.Calendar. The idea behind the design is to encapsulate all target
48 -- dependent machinery in a single package, thus providing a uniform
49 -- interface to all existing and any potential children.
51 -- package Ada.Calendar
52 -- procedure Split (5 parameters) -------+
53 -- | Call from local routine
55 -- package Formatting_Operations |
56 -- procedure Split (11 parameters) <--+
57 -- end Formatting_Operations |
60 -- package Ada.Calendar.Formatting | Call from child routine
61 -- procedure Split (9 or 10 parameters) -+
62 -- end Ada.Calendar.Formatting
64 -- The behaviour of the interfacing routines is controlled via various
65 -- flags. All new Ada 2005 types from children of Ada.Calendar are
66 -- emulated by a similar type. For instance, type Day_Number is replaced
67 -- by Integer in various routines. One ramification of this model is that
68 -- the caller site must perform validity checks on returned results.
69 -- The end result of this model is the lack of target specific files per
70 -- child of Ada.Calendar (a-calfor, a-calfor-vms, a-calfor-vxwors, etc).
72 -----------------------
73 -- Local Subprograms --
74 -----------------------
76 procedure Check_Within_Time_Bounds (T : Time_Rep);
77 -- Ensure that a time representation value falls withing the bounds of Ada
78 -- time. Leap seconds support is taken into account.
80 procedure Cumulative_Leap_Seconds
81 (Start_Date : Time_Rep;
83 Elapsed_Leaps : out Natural;
84 Next_Leap : out Time_Rep);
85 -- Elapsed_Leaps is the sum of the leap seconds that have occurred on or
86 -- after Start_Date and before (strictly before) End_Date. Next_Leap_Sec
87 -- represents the next leap second occurrence on or after End_Date. If
88 -- there are no leaps seconds after End_Date, End_Of_Time is returned.
89 -- End_Of_Time can be used as End_Date to count all the leap seconds that
90 -- have occurred on or after Start_Date.
92 -- Note: Any sub seconds of Start_Date and End_Date are discarded before
93 -- the calculations are done. For instance: if 113 seconds is a leap
94 -- second (it isn't) and 113.5 is input as an End_Date, the leap second
95 -- at 113 will not be counted in Leaps_Between, but it will be returned
96 -- as Next_Leap_Sec. Thus, if the caller wants to know if the End_Date is
97 -- a leap second, the comparison should be:
99 -- End_Date >= Next_Leap_Sec;
101 -- After_Last_Leap is designed so that this comparison works without
102 -- having to first check if Next_Leap_Sec is a valid leap second.
104 function Duration_To_Time_Rep is
105 new Ada.Unchecked_Conversion (Duration, Time_Rep);
106 -- Convert a duration value into a time representation value
108 function Time_Rep_To_Duration is
109 new Ada.Unchecked_Conversion (Time_Rep, Duration);
110 -- Convert a time representation value into a duration value
116 -- An integer time duration. The type is used whenever a positive elapsed
117 -- duration is needed, for instance when splitting a time value. Here is
118 -- how Time_Rep and Time_Dur are related:
120 -- 'First Ada_Low Ada_High 'Last
121 -- Time_Rep: +-------+------------------------+---------+
122 -- Time_Dur: +------------------------+---------+
125 type Time_Dur is range 0 .. 2 ** 63 - 1;
127 --------------------------
128 -- Leap seconds control --
129 --------------------------
132 pragma Import (C, Flag, "__gl_leap_seconds_support");
133 -- This imported value is used to determine whether the compilation had
134 -- binder flag "-y" present which enables leap seconds. A value of zero
135 -- signifies no leap seconds support while a value of one enables the
138 Leap_Support : constant Boolean := Flag = 1;
139 -- The above flag controls the usage of leap seconds in all Ada.Calendar
142 Leap_Seconds_Count : constant Natural := 23;
144 ---------------------
145 -- Local Constants --
146 ---------------------
148 Ada_Min_Year : constant Year_Number := Year_Number'First;
149 Secs_In_Four_Years : constant := (3 * 365 + 366) * Secs_In_Day;
150 Secs_In_Non_Leap_Year : constant := 365 * Secs_In_Day;
152 -- Lower and upper bound of Ada time. The zero (0) value of type Time is
153 -- positioned at year 2150. Note that the lower and upper bound account
154 -- for the non-leap centennial years.
156 Ada_Low : constant Time_Rep := -(61 * 366 + 188 * 365) * Nanos_In_Day;
157 Ada_High : constant Time_Rep := (60 * 366 + 190 * 365) * Nanos_In_Day;
159 -- Even though the upper bound of time is 2399-12-31 23:59:59.999999999
160 -- UTC, it must be increased to include all leap seconds.
162 Ada_High_And_Leaps : constant Time_Rep :=
163 Ada_High + Time_Rep (Leap_Seconds_Count) * Nano;
165 -- Two constants used in the calculations of elapsed leap seconds.
166 -- End_Of_Time is later than Ada_High in time zone -28. Start_Of_Time
167 -- is earlier than Ada_Low in time zone +28.
169 End_Of_Time : constant Time_Rep :=
170 Ada_High + Time_Rep (3) * Nanos_In_Day;
171 Start_Of_Time : constant Time_Rep :=
172 Ada_Low - Time_Rep (3) * Nanos_In_Day;
174 -- The Unix lower time bound expressed as nanoseconds since the
175 -- start of Ada time in UTC.
177 Unix_Min : constant Time_Rep :=
178 Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
180 Epoch_Offset : constant Time_Rep := (136 * 365 + 44 * 366) * Nanos_In_Day;
181 -- The difference between 2150-1-1 UTC and 1970-1-1 UTC expressed in
182 -- nanoseconds. Note that year 2100 is non-leap.
184 Cumulative_Days_Before_Month :
185 constant array (Month_Number) of Natural :=
186 (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334);
188 -- The following table contains the hard time values of all existing leap
189 -- seconds. The values are produced by the utility program xleaps.adb.
191 Leap_Second_Times : constant array (1 .. Leap_Seconds_Count) of Time_Rep :=
192 (-5601484800000000000,
193 -5585587199000000000,
194 -5554051198000000000,
195 -5522515197000000000,
196 -5490979196000000000,
197 -5459356795000000000,
198 -5427820794000000000,
199 -5396284793000000000,
200 -5364748792000000000,
201 -5317487991000000000,
202 -5285951990000000000,
203 -5254415989000000000,
204 -5191257588000000000,
205 -5112287987000000000,
206 -5049129586000000000,
207 -5017593585000000000,
208 -4970332784000000000,
209 -4938796783000000000,
210 -4907260782000000000,
211 -4859827181000000000,
212 -4812566380000000000,
213 -4765132779000000000,
214 -4544207978000000000);
220 function "+" (Left : Time; Right : Duration) return Time is
221 pragma Unsuppress (Overflow_Check);
222 Left_N : constant Time_Rep := Time_Rep (Left);
224 return Time (Left_N + Duration_To_Time_Rep (Right));
226 when Constraint_Error =>
230 function "+" (Left : Duration; Right : Time) return Time is
239 function "-" (Left : Time; Right : Duration) return Time is
240 pragma Unsuppress (Overflow_Check);
241 Left_N : constant Time_Rep := Time_Rep (Left);
243 return Time (Left_N - Duration_To_Time_Rep (Right));
245 when Constraint_Error =>
249 function "-" (Left : Time; Right : Time) return Duration is
250 pragma Unsuppress (Overflow_Check);
252 -- The bounds of type Duration expressed as time representations
254 Dur_Low : constant Time_Rep := Duration_To_Time_Rep (Duration'First);
255 Dur_High : constant Time_Rep := Duration_To_Time_Rep (Duration'Last);
260 Res_N := Time_Rep (Left) - Time_Rep (Right);
262 -- Due to the extended range of Ada time, "-" is capable of producing
263 -- results which may exceed the range of Duration. In order to prevent
264 -- the generation of bogus values by the Unchecked_Conversion, we apply
265 -- the following check.
268 or else Res_N > Dur_High
273 return Time_Rep_To_Duration (Res_N);
275 when Constraint_Error =>
283 function "<" (Left, Right : Time) return Boolean is
285 return Time_Rep (Left) < Time_Rep (Right);
292 function "<=" (Left, Right : Time) return Boolean is
294 return Time_Rep (Left) <= Time_Rep (Right);
301 function ">" (Left, Right : Time) return Boolean is
303 return Time_Rep (Left) > Time_Rep (Right);
310 function ">=" (Left, Right : Time) return Boolean is
312 return Time_Rep (Left) >= Time_Rep (Right);
315 ------------------------------
316 -- Check_Within_Time_Bounds --
317 ------------------------------
319 procedure Check_Within_Time_Bounds (T : Time_Rep) is
322 if T < Ada_Low or else T > Ada_High_And_Leaps then
326 if T < Ada_Low or else T > Ada_High then
330 end Check_Within_Time_Bounds;
336 function Clock return Time is
337 Elapsed_Leaps : Natural;
338 Next_Leap_N : Time_Rep;
340 -- The system clock returns the time in UTC since the Unix Epoch of
341 -- 1970-01-01 00:00:00.0. We perform an origin shift to the Ada Epoch
342 -- by adding the number of nanoseconds between the two origins.
345 Duration_To_Time_Rep (System.OS_Primitives.Clock) +
349 -- If the target supports leap seconds, determine the number of leap
350 -- seconds elapsed until this moment.
353 Cumulative_Leap_Seconds
354 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
356 -- The system clock may fall exactly on a leap second
358 if Res_N >= Next_Leap_N then
359 Elapsed_Leaps := Elapsed_Leaps + 1;
362 -- The target does not support leap seconds
368 Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano;
373 -----------------------------
374 -- Cumulative_Leap_Seconds --
375 -----------------------------
377 procedure Cumulative_Leap_Seconds
378 (Start_Date : Time_Rep;
380 Elapsed_Leaps : out Natural;
381 Next_Leap : out Time_Rep)
383 End_Index : Positive;
384 End_T : Time_Rep := End_Date;
385 Start_Index : Positive;
386 Start_T : Time_Rep := Start_Date;
389 -- Both input dates must be normalized to UTC
391 pragma Assert (Leap_Support and then End_Date >= Start_Date);
393 Next_Leap := End_Of_Time;
395 -- Make sure that the end date does not exceed the upper bound
398 if End_Date > Ada_High then
402 -- Remove the sub seconds from both dates
404 Start_T := Start_T - (Start_T mod Nano);
405 End_T := End_T - (End_T mod Nano);
407 -- Some trivial cases:
408 -- Leap 1 . . . Leap N
409 -- ---+========+------+############+-------+========+-----
410 -- Start_T End_T Start_T End_T
412 if End_T < Leap_Second_Times (1) then
414 Next_Leap := Leap_Second_Times (1);
417 elsif Start_T > Leap_Second_Times (Leap_Seconds_Count) then
419 Next_Leap := End_Of_Time;
423 -- Perform the calculations only if the start date is within the leap
424 -- second occurrences table.
426 if Start_T <= Leap_Second_Times (Leap_Seconds_Count) then
429 -- +----+----+-- . . . --+-------+---+
430 -- | T1 | T2 | | N - 1 | N |
431 -- +----+----+-- . . . --+-------+---+
433 -- | Start_Index | End_Index
434 -- +-------------------+
437 -- The idea behind the algorithm is to iterate and find two
438 -- closest dates which are after Start_T and End_T. Their
439 -- corresponding index difference denotes the number of leap
444 exit when Leap_Second_Times (Start_Index) >= Start_T;
445 Start_Index := Start_Index + 1;
448 End_Index := Start_Index;
450 exit when End_Index > Leap_Seconds_Count
451 or else Leap_Second_Times (End_Index) >= End_T;
452 End_Index := End_Index + 1;
455 if End_Index <= Leap_Seconds_Count then
456 Next_Leap := Leap_Second_Times (End_Index);
459 Elapsed_Leaps := End_Index - Start_Index;
464 end Cumulative_Leap_Seconds;
470 function Day (Date : Time) return Day_Number is
475 pragma Unreferenced (Y, M, S);
477 Split (Date, Y, M, D, S);
485 function Is_Leap (Year : Year_Number) return Boolean is
487 -- Leap centennial years
489 if Year mod 400 = 0 then
492 -- Non-leap centennial years
494 elsif Year mod 100 = 0 then
500 return Year mod 4 = 0;
508 function Month (Date : Time) return Month_Number is
513 pragma Unreferenced (Y, D, S);
515 Split (Date, Y, M, D, S);
523 function Seconds (Date : Time) return Day_Duration is
528 pragma Unreferenced (Y, M, D);
530 Split (Date, Y, M, D, S);
540 Year : out Year_Number;
541 Month : out Month_Number;
542 Day : out Day_Number;
543 Seconds : out Day_Duration)
551 pragma Unreferenced (H, M, Se, Ss, Le);
554 -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will
555 -- ensure that Split picks up the local time zone.
557 Formatting_Operations.Split
574 or else not Month'Valid
575 or else not Day'Valid
576 or else not Seconds'Valid
588 Month : Month_Number;
590 Seconds : Day_Duration := 0.0) return Time
592 -- The values in the following constants are irrelevant, they are just
593 -- placeholders; the choice of constructing a Day_Duration value is
594 -- controlled by the Use_Day_Secs flag.
596 H : constant Integer := 1;
597 M : constant Integer := 1;
598 Se : constant Integer := 1;
599 Ss : constant Duration := 0.1;
605 or else not Month'Valid
606 or else not Day'Valid
607 or else not Seconds'Valid
612 -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will
613 -- ensure that Split picks up the local time zone.
616 Formatting_Operations.Time_Of
626 Use_Day_Secs => True,
635 function Year (Date : Time) return Year_Number is
640 pragma Unreferenced (M, D, S);
642 Split (Date, Y, M, D, S);
646 -- The following packages assume that Time is a signed 64 bit integer
647 -- type, the units are nanoseconds and the origin is the start of Ada
648 -- time (1901-01-01 00:00:00.0 UTC).
650 ---------------------------
651 -- Arithmetic_Operations --
652 ---------------------------
654 package body Arithmetic_Operations is
660 function Add (Date : Time; Days : Long_Integer) return Time is
661 pragma Unsuppress (Overflow_Check);
662 Date_N : constant Time_Rep := Time_Rep (Date);
664 return Time (Date_N + Time_Rep (Days) * Nanos_In_Day);
666 when Constraint_Error =>
677 Days : out Long_Integer;
678 Seconds : out Duration;
679 Leap_Seconds : out Integer)
683 Elapsed_Leaps : Natural;
685 Negate : Boolean := False;
686 Next_Leap_N : Time_Rep;
688 Sub_Secs_Diff : Time_Rep;
691 -- Both input time values are assumed to be in UTC
693 if Left >= Right then
694 Later := Time_Rep (Left);
695 Earlier := Time_Rep (Right);
697 Later := Time_Rep (Right);
698 Earlier := Time_Rep (Left);
702 -- If the target supports leap seconds, process them
705 Cumulative_Leap_Seconds
706 (Earlier, Later, Elapsed_Leaps, Next_Leap_N);
708 if Later >= Next_Leap_N then
709 Elapsed_Leaps := Elapsed_Leaps + 1;
712 -- The target does not support leap seconds
718 -- Sub seconds processing. We add the resulting difference to one
719 -- of the input dates in order to account for any potential rounding
720 -- of the difference in the next step.
722 Sub_Secs_Diff := Later mod Nano - Earlier mod Nano;
723 Earlier := Earlier + Sub_Secs_Diff;
724 Sub_Secs := Duration (Sub_Secs_Diff) / Nano_F;
726 -- Difference processing. This operation should be able to calculate
727 -- the difference between opposite values which are close to the end
728 -- and start of Ada time. To accommodate the large range, we convert
729 -- to seconds. This action may potentially round the two values and
730 -- either add or drop a second. We compensate for this issue in the
734 Time_Dur (Later / Nano - Earlier / Nano) - Time_Dur (Elapsed_Leaps);
736 Days := Long_Integer (Res_Dur / Secs_In_Day);
737 Seconds := Duration (Res_Dur mod Secs_In_Day) + Sub_Secs;
738 Leap_Seconds := Integer (Elapsed_Leaps);
744 if Leap_Seconds /= 0 then
745 Leap_Seconds := -Leap_Seconds;
754 function Subtract (Date : Time; Days : Long_Integer) return Time is
755 pragma Unsuppress (Overflow_Check);
756 Date_N : constant Time_Rep := Time_Rep (Date);
758 return Time (Date_N - Time_Rep (Days) * Nanos_In_Day);
760 when Constraint_Error =>
764 end Arithmetic_Operations;
766 ---------------------------
767 -- Conversion_Operations --
768 ---------------------------
770 package body Conversion_Operations is
776 function To_Ada_Time (Unix_Time : Long_Integer) return Time is
777 pragma Unsuppress (Overflow_Check);
778 Unix_Rep : constant Time_Rep := Time_Rep (Unix_Time) * Nano;
780 return Time (Unix_Rep - Epoch_Offset);
782 when Constraint_Error =>
797 tm_isdst : Integer) return Time
799 pragma Unsuppress (Overflow_Check);
801 Month : Month_Number;
810 Year := Year_Number (1900 + tm_year);
811 Month := Month_Number (1 + tm_mon);
812 Day := Day_Number (tm_day);
814 -- Step 1: Validity checks of input values
817 or else not Month'Valid
818 or else not Day'Valid
819 or else tm_hour not in 0 .. 24
820 or else tm_min not in 0 .. 59
821 or else tm_sec not in 0 .. 60
822 or else tm_isdst not in -1 .. 1
827 -- Step 2: Potential leap second
837 -- Step 3: Calculate the time value
841 (Formatting_Operations.Time_Of
845 Day_Secs => 0.0, -- Time is given in h:m:s
849 Sub_Sec => 0.0, -- No precise sub second given
851 Use_Day_Secs => False, -- Time is given in h:m:s
852 Is_Ada_05 => True, -- Force usage of explicit time zone
853 Time_Zone => 0)); -- Place the value in UTC
855 -- Step 4: Daylight Savings Time
858 Result := Result + Time_Rep (3_600) * Nano;
861 return Time (Result);
864 when Constraint_Error =>
873 (tv_sec : Long_Integer;
874 tv_nsec : Long_Integer) return Duration
876 pragma Unsuppress (Overflow_Check);
878 return Duration (tv_sec) + Duration (tv_nsec) / Nano_F;
881 ------------------------
882 -- To_Struct_Timespec --
883 ------------------------
885 procedure To_Struct_Timespec
887 tv_sec : out Long_Integer;
888 tv_nsec : out Long_Integer)
890 pragma Unsuppress (Overflow_Check);
892 Nano_Secs : Duration;
895 -- Seconds extraction, avoid potential rounding errors
898 tv_sec := Long_Integer (Secs);
900 -- Nanoseconds extraction
902 Nano_Secs := D - Duration (tv_sec);
903 tv_nsec := Long_Integer (Nano_Secs * Nano);
904 end To_Struct_Timespec;
910 procedure To_Struct_Tm
912 tm_year : out Integer;
913 tm_mon : out Integer;
914 tm_day : out Integer;
915 tm_hour : out Integer;
916 tm_min : out Integer;
917 tm_sec : out Integer)
919 pragma Unsuppress (Overflow_Check);
921 Month : Month_Number;
923 Day_Secs : Day_Duration;
928 -- Step 1: Split the input time
930 Formatting_Operations.Split
931 (T, Year, Month, tm_day, Day_Secs,
932 tm_hour, tm_min, Second, Sub_Sec, Leap_Sec, True, 0);
934 -- Step 2: Correct the year and month
936 tm_year := Year - 1900;
939 -- Step 3: Handle leap second occurrences
952 function To_Unix_Time (Ada_Time : Time) return Long_Integer is
953 pragma Unsuppress (Overflow_Check);
954 Ada_Rep : constant Time_Rep := Time_Rep (Ada_Time);
956 return Long_Integer ((Ada_Rep + Epoch_Offset) / Nano);
958 when Constraint_Error =>
961 end Conversion_Operations;
963 ----------------------
964 -- Delay_Operations --
965 ----------------------
967 package body Delay_Operations is
973 function To_Duration (Date : Time) return Duration is
974 pragma Unsuppress (Overflow_Check);
976 Safe_Ada_High : constant Time_Rep := Ada_High - Epoch_Offset;
977 -- This value represents a "safe" end of time. In order to perform a
978 -- proper conversion to Unix duration, we will have to shift origins
979 -- at one point. For very distant dates, this means an overflow check
980 -- failure. To prevent this, the function returns the "safe" end of
981 -- time (roughly 2219) which is still distant enough.
983 Elapsed_Leaps : Natural;
984 Next_Leap_N : Time_Rep;
988 Res_N := Time_Rep (Date);
990 -- Step 1: If the target supports leap seconds, remove any leap
991 -- seconds elapsed up to the input date.
994 Cumulative_Leap_Seconds
995 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
997 -- The input time value may fall on a leap second occurrence
999 if Res_N >= Next_Leap_N then
1000 Elapsed_Leaps := Elapsed_Leaps + 1;
1003 -- The target does not support leap seconds
1009 Res_N := Res_N - Time_Rep (Elapsed_Leaps) * Nano;
1011 -- Step 2: Perform a shift in origins to obtain a Unix equivalent of
1012 -- the input. Guard against very large delay values such as the end
1013 -- of time since the computation will overflow.
1015 if Res_N > Safe_Ada_High then
1016 Res_N := Safe_Ada_High;
1018 Res_N := Res_N + Epoch_Offset;
1021 return Time_Rep_To_Duration (Res_N);
1024 end Delay_Operations;
1026 ---------------------------
1027 -- Formatting_Operations --
1028 ---------------------------
1030 package body Formatting_Operations is
1036 function Day_Of_Week (Date : Time) return Integer is
1047 pragma Unreferenced (Ds, H, Mi, Se, Su, Le);
1049 Day_Count : Long_Integer;
1054 Formatting_Operations.Split
1068 -- Build a time value in the middle of the same day
1072 (Formatting_Operations.Time_Of
1082 Use_Day_Secs => False,
1086 -- Determine the elapsed seconds since the start of Ada time
1088 Res_Dur := Time_Dur (Res_N / Nano - Ada_Low / Nano);
1090 -- Count the number of days since the start of Ada time. 1901-1-1
1091 -- GMT was a Tuesday.
1093 Day_Count := Long_Integer (Res_Dur / Secs_In_Day) + 1;
1095 return Integer (Day_Count mod 7);
1104 Year : out Year_Number;
1105 Month : out Month_Number;
1106 Day : out Day_Number;
1107 Day_Secs : out Day_Duration;
1109 Minute : out Integer;
1110 Second : out Integer;
1111 Sub_Sec : out Duration;
1112 Leap_Sec : out Boolean;
1113 Is_Ada_05 : Boolean;
1114 Time_Zone : Long_Integer)
1116 -- The following constants represent the number of nanoseconds
1117 -- elapsed since the start of Ada time to and including the non
1118 -- leap centennial years.
1120 Year_2101 : constant Time_Rep := Ada_Low +
1121 Time_Rep (49 * 366 + 151 * 365) * Nanos_In_Day;
1122 Year_2201 : constant Time_Rep := Ada_Low +
1123 Time_Rep (73 * 366 + 227 * 365) * Nanos_In_Day;
1124 Year_2301 : constant Time_Rep := Ada_Low +
1125 Time_Rep (97 * 366 + 303 * 365) * Nanos_In_Day;
1127 Date_Dur : Time_Dur;
1129 Day_Seconds : Natural;
1130 Elapsed_Leaps : Natural;
1131 Four_Year_Segs : Natural;
1132 Hour_Seconds : Natural;
1133 Is_Leap_Year : Boolean;
1134 Next_Leap_N : Time_Rep;
1135 Rem_Years : Natural;
1136 Sub_Sec_N : Time_Rep;
1140 Date_N := Time_Rep (Date);
1142 -- Step 1: Leap seconds processing in UTC
1144 if Leap_Support then
1145 Cumulative_Leap_Seconds
1146 (Start_Of_Time, Date_N, Elapsed_Leaps, Next_Leap_N);
1148 Leap_Sec := Date_N >= Next_Leap_N;
1151 Elapsed_Leaps := Elapsed_Leaps + 1;
1154 -- The target does not support leap seconds
1161 Date_N := Date_N - Time_Rep (Elapsed_Leaps) * Nano;
1163 -- Step 2: Time zone processing. This action converts the input date
1164 -- from GMT to the requested time zone.
1167 if Time_Zone /= 0 then
1168 Date_N := Date_N + Time_Rep (Time_Zone) * 60 * Nano;
1175 Off : constant Long_Integer :=
1176 Time_Zones_Operations.UTC_Time_Offset (Time (Date_N));
1178 Date_N := Date_N + Time_Rep (Off) * Nano;
1182 -- Step 3: Non-leap centennial year adjustment in local time zone
1184 -- In order for all divisions to work properly and to avoid more
1185 -- complicated arithmetic, we add fake February 29s to dates which
1186 -- occur after a non-leap centennial year.
1188 if Date_N >= Year_2301 then
1189 Date_N := Date_N + Time_Rep (3) * Nanos_In_Day;
1191 elsif Date_N >= Year_2201 then
1192 Date_N := Date_N + Time_Rep (2) * Nanos_In_Day;
1194 elsif Date_N >= Year_2101 then
1195 Date_N := Date_N + Time_Rep (1) * Nanos_In_Day;
1198 -- Step 4: Sub second processing in local time zone
1200 Sub_Sec_N := Date_N mod Nano;
1201 Sub_Sec := Duration (Sub_Sec_N) / Nano_F;
1202 Date_N := Date_N - Sub_Sec_N;
1204 -- Convert Date_N into a time duration value, changing the units
1207 Date_Dur := Time_Dur (Date_N / Nano - Ada_Low / Nano);
1209 -- Step 5: Year processing in local time zone. Determine the number
1210 -- of four year segments since the start of Ada time and the input
1213 Four_Year_Segs := Natural (Date_Dur / Secs_In_Four_Years);
1215 if Four_Year_Segs > 0 then
1216 Date_Dur := Date_Dur - Time_Dur (Four_Year_Segs) *
1220 -- Calculate the remaining non-leap years
1222 Rem_Years := Natural (Date_Dur / Secs_In_Non_Leap_Year);
1224 if Rem_Years > 3 then
1228 Date_Dur := Date_Dur - Time_Dur (Rem_Years) * Secs_In_Non_Leap_Year;
1230 Year := Ada_Min_Year + Natural (4 * Four_Year_Segs + Rem_Years);
1231 Is_Leap_Year := Is_Leap (Year);
1233 -- Step 6: Month and day processing in local time zone
1235 Year_Day := Natural (Date_Dur / Secs_In_Day) + 1;
1239 -- Processing for months after January
1241 if Year_Day > 31 then
1243 Year_Day := Year_Day - 31;
1245 -- Processing for a new month or a leap February
1248 and then (not Is_Leap_Year or else Year_Day > 29)
1251 Year_Day := Year_Day - 28;
1253 if Is_Leap_Year then
1254 Year_Day := Year_Day - 1;
1259 while Year_Day > Days_In_Month (Month) loop
1260 Year_Day := Year_Day - Days_In_Month (Month);
1266 -- Step 7: Hour, minute, second and sub second processing in local
1269 Day := Day_Number (Year_Day);
1270 Day_Seconds := Integer (Date_Dur mod Secs_In_Day);
1271 Day_Secs := Duration (Day_Seconds) + Sub_Sec;
1272 Hour := Day_Seconds / 3_600;
1273 Hour_Seconds := Day_Seconds mod 3_600;
1274 Minute := Hour_Seconds / 60;
1275 Second := Hour_Seconds mod 60;
1283 (Year : Year_Number;
1284 Month : Month_Number;
1286 Day_Secs : Day_Duration;
1291 Leap_Sec : Boolean := False;
1292 Use_Day_Secs : Boolean := False;
1293 Is_Ada_05 : Boolean := False;
1294 Time_Zone : Long_Integer := 0) return Time
1297 Elapsed_Leaps : Natural;
1298 Next_Leap_N : Time_Rep;
1300 Rounded_Res_N : Time_Rep;
1303 -- Step 1: Check whether the day, month and year form a valid date
1305 if Day > Days_In_Month (Month)
1306 and then (Day /= 29 or else Month /= 2 or else not Is_Leap (Year))
1311 -- Start accumulating nanoseconds from the low bound of Ada time
1315 -- Step 2: Year processing and centennial year adjustment. Determine
1316 -- the number of four year segments since the start of Ada time and
1319 Count := (Year - Year_Number'First) / 4;
1320 Res_N := Res_N + Time_Rep (Count) * Secs_In_Four_Years * Nano;
1322 -- Note that non-leap centennial years are automatically considered
1323 -- leap in the operation above. An adjustment of several days is
1324 -- required to compensate for this.
1327 Res_N := Res_N - Time_Rep (3) * Nanos_In_Day;
1329 elsif Year > 2200 then
1330 Res_N := Res_N - Time_Rep (2) * Nanos_In_Day;
1332 elsif Year > 2100 then
1333 Res_N := Res_N - Time_Rep (1) * Nanos_In_Day;
1336 -- Add the remaining non-leap years
1338 Count := (Year - Year_Number'First) mod 4;
1339 Res_N := Res_N + Time_Rep (Count) * Secs_In_Non_Leap_Year * Nano;
1341 -- Step 3: Day of month processing. Determine the number of days
1342 -- since the start of the current year. Do not add the current
1343 -- day since it has not elapsed yet.
1345 Count := Cumulative_Days_Before_Month (Month) + Day - 1;
1347 -- The input year is leap and we have passed February
1355 Res_N := Res_N + Time_Rep (Count) * Nanos_In_Day;
1357 -- Step 4: Hour, minute, second and sub second processing
1359 if Use_Day_Secs then
1360 Res_N := Res_N + Duration_To_Time_Rep (Day_Secs);
1364 Time_Rep (Hour * 3_600 + Minute * 60 + Second) * Nano;
1366 if Sub_Sec = 1.0 then
1367 Res_N := Res_N + Time_Rep (1) * Nano;
1369 Res_N := Res_N + Duration_To_Time_Rep (Sub_Sec);
1373 -- At this point, the generated time value should be withing the
1374 -- bounds of Ada time.
1376 Check_Within_Time_Bounds (Res_N);
1378 -- Step 4: Time zone processing. At this point we have built an
1379 -- arbitrary time value which is not related to any time zone.
1380 -- For simplicity, the time value is normalized to GMT, producing
1381 -- a uniform representation which can be treated by arithmetic
1382 -- operations for instance without any additional corrections.
1385 if Time_Zone /= 0 then
1386 Res_N := Res_N - Time_Rep (Time_Zone) * 60 * Nano;
1393 Current_Off : constant Long_Integer :=
1394 Time_Zones_Operations.UTC_Time_Offset
1396 Current_Res_N : constant Time_Rep :=
1397 Res_N - Time_Rep (Current_Off) * Nano;
1398 Off : constant Long_Integer :=
1399 Time_Zones_Operations.UTC_Time_Offset
1400 (Time (Current_Res_N));
1402 Res_N := Res_N - Time_Rep (Off) * Nano;
1406 -- Step 5: Leap seconds processing in GMT
1408 if Leap_Support then
1409 Cumulative_Leap_Seconds
1410 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
1412 Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano;
1414 -- An Ada 2005 caller requesting an explicit leap second or an
1415 -- Ada 95 caller accounting for an invisible leap second.
1418 or else Res_N >= Next_Leap_N
1420 Res_N := Res_N + Time_Rep (1) * Nano;
1423 -- Leap second validity check
1425 Rounded_Res_N := Res_N - (Res_N mod Nano);
1429 and then Rounded_Res_N /= Next_Leap_N
1435 return Time (Res_N);
1438 end Formatting_Operations;
1440 ---------------------------
1441 -- Time_Zones_Operations --
1442 ---------------------------
1444 package body Time_Zones_Operations is
1446 -- The Unix time bounds in nanoseconds: 1970/1/1 .. 2037/1/1
1448 Unix_Min : constant Time_Rep := Ada_Low +
1449 Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
1451 Unix_Max : constant Time_Rep := Ada_Low +
1452 Time_Rep (34 * 366 + 102 * 365) * Nanos_In_Day +
1453 Time_Rep (Leap_Seconds_Count) * Nano;
1455 -- The following constants denote February 28 during non-leap
1456 -- centennial years, the units are nanoseconds.
1458 T_2100_2_28 : constant Time_Rep := Ada_Low +
1459 (Time_Rep (49 * 366 + 150 * 365 + 59) * Secs_In_Day +
1460 Time_Rep (Leap_Seconds_Count)) * Nano;
1462 T_2200_2_28 : constant Time_Rep := Ada_Low +
1463 (Time_Rep (73 * 366 + 226 * 365 + 59) * Secs_In_Day +
1464 Time_Rep (Leap_Seconds_Count)) * Nano;
1466 T_2300_2_28 : constant Time_Rep := Ada_Low +
1467 (Time_Rep (97 * 366 + 302 * 365 + 59) * Secs_In_Day +
1468 Time_Rep (Leap_Seconds_Count)) * Nano;
1470 -- 56 years (14 leap years + 42 non leap years) in nanoseconds:
1472 Nanos_In_56_Years : constant := (14 * 366 + 42 * 365) * Nanos_In_Day;
1474 -- Base C types. There is no point dragging in Interfaces.C just for
1475 -- these four types.
1477 type char_Pointer is access Character;
1478 subtype int is Integer;
1479 subtype long is Long_Integer;
1480 type long_Pointer is access all long;
1482 -- The Ada equivalent of struct tm and type time_t
1485 tm_sec : int; -- seconds after the minute (0 .. 60)
1486 tm_min : int; -- minutes after the hour (0 .. 59)
1487 tm_hour : int; -- hours since midnight (0 .. 24)
1488 tm_mday : int; -- day of the month (1 .. 31)
1489 tm_mon : int; -- months since January (0 .. 11)
1490 tm_year : int; -- years since 1900
1491 tm_wday : int; -- days since Sunday (0 .. 6)
1492 tm_yday : int; -- days since January 1 (0 .. 365)
1493 tm_isdst : int; -- Daylight Savings Time flag (-1 .. 1)
1494 tm_gmtoff : long; -- offset from UTC in seconds
1495 tm_zone : char_Pointer; -- timezone abbreviation
1498 type tm_Pointer is access all tm;
1500 subtype time_t is long;
1501 type time_t_Pointer is access all time_t;
1503 procedure localtime_tzoff
1504 (C : time_t_Pointer;
1506 off : long_Pointer);
1507 pragma Import (C, localtime_tzoff, "__gnat_localtime_tzoff");
1508 -- This is a lightweight wrapper around the system library function
1509 -- localtime_r. Parameter 'off' captures the UTC offset which is either
1510 -- retrieved from the tm struct or calculated from the 'timezone' extern
1511 -- and the tm_isdst flag in the tm struct.
1513 ---------------------
1514 -- UTC_Time_Offset --
1515 ---------------------
1517 function UTC_Time_Offset (Date : Time) return Long_Integer is
1518 Adj_Cent : Integer := 0;
1520 Offset : aliased long;
1521 Secs_T : aliased time_t;
1522 Secs_TM : aliased tm;
1525 Date_N := Time_Rep (Date);
1527 -- Dates which are 56 years apart fall on the same day, day light
1528 -- saving and so on. Non-leap centennial years violate this rule by
1529 -- one day and as a consequence, special adjustment is needed.
1531 if Date_N > T_2100_2_28 then
1532 if Date_N > T_2200_2_28 then
1533 if Date_N > T_2300_2_28 then
1544 if Adj_Cent > 0 then
1545 Date_N := Date_N - Time_Rep (Adj_Cent) * Nanos_In_Day;
1548 -- Shift the date within bounds of Unix time
1550 while Date_N < Unix_Min loop
1551 Date_N := Date_N + Nanos_In_56_Years;
1554 while Date_N >= Unix_Max loop
1555 Date_N := Date_N - Nanos_In_56_Years;
1558 -- Perform a shift in origins from Ada to Unix
1560 Date_N := Date_N - Unix_Min;
1562 -- Convert the date into seconds
1564 Secs_T := time_t (Date_N / Nano);
1567 (Secs_T'Unchecked_Access,
1568 Secs_TM'Unchecked_Access,
1569 Offset'Unchecked_Access);
1572 end UTC_Time_Offset;
1574 end Time_Zones_Operations;
1576 -- Start of elaboration code for Ada.Calendar
1579 System.OS_Primitives.Initialize;