| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- A D A . C A L E N D A R -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2009, Free Software Foundation, Inc. -- |
| -- -- |
| -- This specification is derived from the Ada Reference Manual for use with -- |
| -- GNAT. The copyright notice above, and the license provisions that follow -- |
| -- apply solely to the contents of the part following the private keyword. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| package Ada.Calendar is |
| |
| type Time is private; |
| |
| -- Declarations representing limits of allowed local time values. Note that |
| -- these do NOT constrain the possible stored values of time which may well |
| -- permit a larger range of times (this is explicitly allowed in Ada 95). |
| |
| subtype Year_Number is Integer range 1901 .. 2399; |
| subtype Month_Number is Integer range 1 .. 12; |
| subtype Day_Number is Integer range 1 .. 31; |
| |
| -- A Day_Duration value of 86_400.0 designates a new day |
| |
| subtype Day_Duration is Duration range 0.0 .. 86_400.0; |
| |
| function Clock return Time; |
| -- The returned time value is the number of nanoseconds since the start |
| -- of Ada time (1901-01-01 00:00:00.0 UTC). If leap seconds are enabled, |
| -- the result will contain all elapsed leap seconds since the start of |
| -- Ada time until now. |
| |
| function Year (Date : Time) return Year_Number; |
| function Month (Date : Time) return Month_Number; |
| function Day (Date : Time) return Day_Number; |
| function Seconds (Date : Time) return Day_Duration; |
| |
| procedure Split |
| (Date : Time; |
| Year : out Year_Number; |
| Month : out Month_Number; |
| Day : out Day_Number; |
| Seconds : out Day_Duration); |
| -- Break down a time value into its date components set in the current |
| -- time zone. If Split is called on a time value created using Ada 2005 |
| -- Time_Of in some arbitrary time zone, the input value will always be |
| -- interpreted as relative to the local time zone. |
| |
| function Time_Of |
| (Year : Year_Number; |
| Month : Month_Number; |
| Day : Day_Number; |
| Seconds : Day_Duration := 0.0) return Time; |
| -- GNAT Note: Normally when procedure Split is called on a Time value |
| -- result of a call to function Time_Of, the out parameters of procedure |
| -- Split are identical to the in parameters of function Time_Of. However, |
| -- when a non-existent time of day is specified, the values for Seconds |
| -- may or may not be different. This may happen when Daylight Saving Time |
| -- (DST) is in effect, on the day when switching to DST, if Seconds |
| -- specifies a time of day in the hour that does not exist. For example, |
| -- in New York: |
| -- |
| -- Time_Of (Year => 1998, Month => 4, Day => 5, Seconds => 10740.0) |
| -- |
| -- will return a Time value T. If Split is called on T, the resulting |
| -- Seconds may be 14340.0 (3:59:00) instead of 10740.0 (2:59:00 being |
| -- a time that not exist). |
| |
| function "+" (Left : Time; Right : Duration) return Time; |
| function "+" (Left : Duration; Right : Time) return Time; |
| function "-" (Left : Time; Right : Duration) return Time; |
| function "-" (Left : Time; Right : Time) return Duration; |
| -- The first three functions will raise Time_Error if the resulting time |
| -- value is less than the start of Ada time in UTC or greater than the |
| -- end of Ada time in UTC. The last function will raise Time_Error if the |
| -- resulting difference cannot fit into a duration value. |
| |
| function "<" (Left, Right : Time) return Boolean; |
| function "<=" (Left, Right : Time) return Boolean; |
| function ">" (Left, Right : Time) return Boolean; |
| function ">=" (Left, Right : Time) return Boolean; |
| |
| Time_Error : exception; |
| |
| private |
| pragma Inline (Clock); |
| |
| pragma Inline (Year); |
| pragma Inline (Month); |
| pragma Inline (Day); |
| |
| pragma Inline ("+"); |
| pragma Inline ("-"); |
| |
| pragma Inline ("<"); |
| pragma Inline ("<="); |
| pragma Inline (">"); |
| pragma Inline (">="); |
| |
| -- The units used in this version of Ada.Calendar are nanoseconds. The |
| -- following constants provide values used in conversions of seconds or |
| -- days to the underlying units. |
| |
| Nano : constant := 1_000_000_000; |
| Nano_F : constant := 1_000_000_000.0; |
| Nanos_In_Day : constant := 86_400_000_000_000; |
| Secs_In_Day : constant := 86_400; |
| |
| ---------------------------- |
| -- Implementation of Time -- |
| ---------------------------- |
| |
| -- Time is represented as a signed 64 bit integer count of nanoseconds |
| -- since the start of Ada time (1901-01-01 00:00:00.0 UTC). Time values |
| -- produced by Time_Of are internally normalized to UTC regardless of their |
| -- local time zone. This representation ensures correct handling of leap |
| -- seconds as well as performing arithmetic. In Ada 95, Split and Time_Of |
| -- will treat a time value as being in the local time zone, in Ada 2005, |
| -- Split and Time_Of will treat a time value as being in the designated |
| -- time zone by the formal parameter or in UTC by default. The size of the |
| -- type is large enough to cover the Ada 2005 range of time (1901-01-01 |
| -- 00:00:00.0 UTC - 2399-12-31-23:59:59.999999999 UTC). |
| |
| ------------------ |
| -- Leap seconds -- |
| ------------------ |
| |
| -- Due to Earth's slowdown, the astronomical time is not as precise as the |
| -- International Atomic Time. To compensate for this inaccuracy, a single |
| -- leap second is added after the last day of June or December. The count |
| -- of seconds during those occurrences becomes: |
| |
| -- ... 58, 59, leap second 60, 0, 1, 2 ... |
| |
| -- Unlike leap days, leap seconds occur simultaneously around the world. |
| -- In other words, if a leap second occurs at 23:59:60 UTC, it also occurs |
| -- on 18:59:60 -5 the same day or 2:59:60 +2 on the next day. |
| |
| -- Leap seconds do not follow a formula. The International Earth Rotation |
| -- and Reference System Service decides when to add one. Leap seconds are |
| -- included in the representation of time in Ada 95 mode. As a result, |
| -- the following two time values will differ by two seconds: |
| |
| -- 1972-06-30 23:59:59.0 |
| -- 1972-07-01 00:00:00.0 |
| |
| -- When a new leap second is introduced, the following steps must be |
| -- carried out: |
| |
| -- 1) Increment Leap_Seconds_Count in a-calend.adb by one |
| -- 2) Increment LS_Count in xleaps.adb by one |
| -- 3) Add the new date to the aggregate of array LS_Dates in |
| -- xleaps.adb |
| -- 4) Compile and execute xleaps |
| -- 5) Replace the values of Leap_Second_Times in a-calend.adb with the |
| -- aggregate generated by xleaps |
| |
| -- The algorithms that build the actual leap second values and discover |
| -- how many leap seconds have occurred between two dates do not need any |
| -- modification. |
| |
| ------------------------------ |
| -- Non-leap centennial years -- |
| ------------------------------ |
| |
| -- Over the range of Ada time, centennial years 2100, 2200 and 2300 are |
| -- non-leap. As a consequence, seven non-leap years occur over the period |
| -- of year - 4 to year + 4. Internally, routines Split and Time_Of add or |
| -- subtract a "fake" February 29 to facilitate the arithmetic involved. |
| |
| -- The underlying type of Time has been chosen to be a 64 bit signed |
| -- integer number since it allows for easier processing of sub seconds |
| -- and arithmetic. |
| |
| type Time_Rep is range -2 ** 63 .. +2 ** 63 - 1; |
| type Time is new Time_Rep; |
| |
| Days_In_Month : constant array (Month_Number) of Day_Number := |
| (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); |
| |
| Invalid_Time_Zone_Offset : Long_Integer; |
| pragma Import (C, Invalid_Time_Zone_Offset, "__gnat_invalid_tzoff"); |
| |
| function Is_Leap (Year : Year_Number) return Boolean; |
| -- Determine whether a given year is leap |
| |
| -- The following packages provide a target independent interface to the |
| -- children of Calendar - Arithmetic, Conversions, Delays, Formatting and |
| -- Time_Zones. |
| |
| --------------------------- |
| -- Arithmetic_Operations -- |
| --------------------------- |
| |
| package Arithmetic_Operations is |
| |
| function Add (Date : Time; Days : Long_Integer) return Time; |
| -- Add a certain number of days to a time value |
| |
| procedure Difference |
| (Left : Time; |
| Right : Time; |
| Days : out Long_Integer; |
| Seconds : out Duration; |
| Leap_Seconds : out Integer); |
| -- Calculate the difference between two time values in terms of days, |
| -- seconds and leap seconds elapsed. The leap seconds are not included |
| -- in the seconds returned. If Left is greater than Right, the returned |
| -- values are positive, negative otherwise. |
| |
| function Subtract (Date : Time; Days : Long_Integer) return Time; |
| -- Subtract a certain number of days from a time value |
| |
| end Arithmetic_Operations; |
| |
| --------------------------- |
| -- Conversion_Operations -- |
| --------------------------- |
| |
| package Conversion_Operations is |
| |
| function To_Ada_Time (Unix_Time : Long_Integer) return Time; |
| -- Unix to Ada Epoch conversion |
| |
| 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; |
| -- Struct tm to Ada Epoch conversion |
| |
| function To_Duration |
| (tv_sec : Long_Integer; |
| tv_nsec : Long_Integer) return Duration; |
| -- Struct timespec to Duration conversion |
| |
| procedure To_Struct_Timespec |
| (D : Duration; |
| tv_sec : out Long_Integer; |
| tv_nsec : out Long_Integer); |
| -- Duration to struct timespec conversion |
| |
| 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); |
| -- Time to struct tm conversion |
| |
| function To_Unix_Time (Ada_Time : Time) return Long_Integer; |
| -- Ada to Unix Epoch conversion |
| |
| end Conversion_Operations; |
| |
| ---------------------- |
| -- Delay_Operations -- |
| ---------------------- |
| |
| package Delay_Operations is |
| |
| function To_Duration (Date : Time) return Duration; |
| -- Given a time value in nanoseconds since 1901, convert it into a |
| -- duration value giving the number of nanoseconds since the Unix Epoch. |
| |
| end Delay_Operations; |
| |
| --------------------------- |
| -- Formatting_Operations -- |
| --------------------------- |
| |
| package Formatting_Operations is |
| |
| function Day_Of_Week (Date : Time) return Integer; |
| -- Determine which day of week Date falls on. The returned values are |
| -- within the range of 0 .. 6 (Monday .. Sunday). |
| |
| procedure Split |
| (Date : Time; |
| Year : out Year_Number; |
| Month : out Month_Number; |
| Day : out Day_Number; |
| Day_Secs : out Day_Duration; |
| Hour : out Integer; |
| Minute : out Integer; |
| Second : out Integer; |
| Sub_Sec : out Duration; |
| Leap_Sec : out Boolean; |
| Is_Ada_05 : Boolean; |
| Time_Zone : Long_Integer); |
| -- Split a time value into its components. Set Is_Ada_05 to use the |
| -- local time zone (the value in Time_Zone is ignored) when splitting |
| -- a time value. |
| |
| function Time_Of |
| (Year : Year_Number; |
| Month : Month_Number; |
| Day : Day_Number; |
| Day_Secs : Day_Duration; |
| Hour : Integer; |
| Minute : Integer; |
| Second : Integer; |
| Sub_Sec : Duration; |
| Leap_Sec : Boolean := False; |
| Use_Day_Secs : Boolean := False; |
| Is_Ada_05 : Boolean := False; |
| Time_Zone : Long_Integer := 0) return Time; |
| -- Given all the components of a date, return the corresponding time |
| -- value. Set Use_Day_Secs to use the value in Day_Secs, otherwise the |
| -- day duration will be calculated from Hour, Minute, Second and Sub_ |
| -- Sec. Set Is_Ada_05 to use the local time zone (the value in formal |
| -- Time_Zone is ignored) when building a time value and to verify the |
| -- validity of a requested leap second. |
| |
| end Formatting_Operations; |
| |
| --------------------------- |
| -- Time_Zones_Operations -- |
| --------------------------- |
| |
| package Time_Zones_Operations is |
| |
| function UTC_Time_Offset (Date : Time) return Long_Integer; |
| -- Return the offset in seconds from UTC |
| |
| end Time_Zones_Operations; |
| |
| end Ada.Calendar; |
