383 lines
16 KiB
Ada
383 lines
16 KiB
Ada
------------------------------------------------------------------------------
|
|
-- --
|
|
-- GNAT RUN-TIME COMPONENTS --
|
|
-- --
|
|
-- A D A . C A L E N D A R --
|
|
-- --
|
|
-- S p e c --
|
|
-- --
|
|
-- Copyright (C) 1992-2014, 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.
|
|
|
|
------------------------
|
|
-- Local Declarations --
|
|
------------------------
|
|
|
|
type Time_Rep is new Long_Long_Integer;
|
|
type Time is new Time_Rep;
|
|
-- 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. We use Long_Long_Integer to allow this unit to compile
|
|
-- when using custom target configuration files where the max integer is
|
|
-- 32 bits. This is useful for static analysis tools such as SPARK or
|
|
-- CodePeer.
|
|
--
|
|
-- Note: the reason we have two separate types here is to avoid problems
|
|
-- with overloading ambiguities in the body if we tried to use Time as an
|
|
-- internal computational type.
|
|
|
|
Days_In_Month : constant array (Month_Number) of Day_Number :=
|
|
(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
|
|
-- Days in month for non-leap year, leap year case is adjusted in code
|
|
|
|
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
|
|
|
|
----------------------------------------------------------
|
|
-- Target-Independent Interface to Children of Calendar --
|
|
----------------------------------------------------------
|
|
|
|
-- 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;
|
|
Use_TZ : Boolean;
|
|
Is_Historic : Boolean;
|
|
Time_Zone : Long_Integer);
|
|
pragma Export (Ada, Split, "__gnat_split");
|
|
-- Split a time value into its components. If flag Is_Historic is set,
|
|
-- this routine would try to use to the best of the OS's abilities the
|
|
-- time zone offset that was or will be in effect on Date. Set Use_TZ
|
|
-- 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;
|
|
Use_Day_Secs : Boolean;
|
|
Use_TZ : Boolean;
|
|
Is_Historic : Boolean;
|
|
Time_Zone : Long_Integer) return Time;
|
|
pragma Export (Ada, Time_Of, "__gnat_time_of");
|
|
-- 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. If flag Is_Historic is set, this routine would try to use to the
|
|
-- best of the OS's abilities the time zone offset that was or will be
|
|
-- in effect on the input date. Set Use_TZ 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 (in seconds) the difference between the local time zone and
|
|
-- UTC time at a specific historic date.
|
|
|
|
end Time_Zones_Operations;
|
|
|
|
end Ada.Calendar;
|