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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- G N A T . C A L E N D A R --
-- --
-- B o d y --
-- --
-- Copyright (C) 1999-2022, AdaCore --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Interfaces.C.Extensions;
package body GNAT.Calendar is
use Ada.Calendar;
use Interfaces;
-----------------
-- Day_In_Year --
-----------------
function Day_In_Year (Date : Time) return Day_In_Year_Number is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Day_Secs : Day_Duration;
begin
Split (Date, Year, Month, Day, Day_Secs);
return Julian_Day (Year, Month, Day) - Julian_Day (Year, 1, 1) + 1;
end Day_In_Year;
-----------------
-- Day_Of_Week --
-----------------
function Day_Of_Week (Date : Time) return Day_Name is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Day_Secs : Day_Duration;
begin
Split (Date, Year, Month, Day, Day_Secs);
return Day_Name'Val ((Julian_Day (Year, Month, Day)) mod 7);
end Day_Of_Week;
----------
-- Hour --
----------
function Hour (Date : Time) return Hour_Number is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration;
begin
Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
return Hour;
end Hour;
----------------
-- Julian_Day --
----------------
-- Julian_Day is used to by Day_Of_Week and Day_In_Year. Note that this
-- implementation is not expensive.
function Julian_Day
(Year : Year_Number;
Month : Month_Number;
Day : Day_Number) return Integer
is
Internal_Year : Integer;
Internal_Month : Integer;
Internal_Day : Integer;
Julian_Date : Integer;
C : Integer;
Ya : Integer;
begin
Internal_Year := Integer (Year);
Internal_Month := Integer (Month);
Internal_Day := Integer (Day);
if Internal_Month > 2 then
Internal_Month := Internal_Month - 3;
else
Internal_Month := Internal_Month + 9;
Internal_Year := Internal_Year - 1;
end if;
C := Internal_Year / 100;
Ya := Internal_Year - (100 * C);
Julian_Date := (146_097 * C) / 4 +
(1_461 * Ya) / 4 +
(153 * Internal_Month + 2) / 5 +
Internal_Day + 1_721_119;
return Julian_Date;
end Julian_Day;
------------
-- Minute --
------------
function Minute (Date : Time) return Minute_Number is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration;
begin
Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
return Minute;
end Minute;
------------
-- Second --
------------
function Second (Date : Time) return Second_Number is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration;
begin
Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
return Second;
end Second;
-----------
-- Split --
-----------
procedure Split
(Date : Time;
Year : out Year_Number;
Month : out Month_Number;
Day : out Day_Number;
Hour : out Hour_Number;
Minute : out Minute_Number;
Second : out Second_Number;
Sub_Second : out Second_Duration)
is
Day_Secs : Day_Duration;
Secs : Natural;
begin
Split (Date, Year, Month, Day, Day_Secs);
Secs := (if Day_Secs = 0.0 then 0 else Natural (Day_Secs - 0.5));
Sub_Second := Second_Duration (Day_Secs - Day_Duration (Secs));
Hour := Hour_Number (Secs / 3_600);
Secs := Secs mod 3_600;
Minute := Minute_Number (Secs / 60);
Second := Second_Number (Secs mod 60);
end Split;
---------------------
-- Split_At_Locale --
---------------------
procedure Split_At_Locale
(Date : Time;
Year : out Year_Number;
Month : out Month_Number;
Day : out Day_Number;
Hour : out Hour_Number;
Minute : out Minute_Number;
Second : out Second_Number;
Sub_Second : out Second_Duration)
is
procedure Ada_Calendar_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 Import (Ada, Ada_Calendar_Split, "__gnat_split");
Ds : Day_Duration;
Le : Boolean;
begin
-- Even though the input time zone is UTC (0), the flag Use_TZ will
-- ensure that Split picks up the local time zone. ???But Use_TZ is
-- False below, and anyway, Use_TZ has no effect if Time_Zone is 0.
Ada_Calendar_Split
(Date => Date,
Year => Year,
Month => Month,
Day => Day,
Day_Secs => Ds,
Hour => Hour,
Minute => Minute,
Second => Second,
Sub_Sec => Sub_Second,
Leap_Sec => Le,
Use_TZ => False,
Is_Historic => False,
Time_Zone => 0);
end Split_At_Locale;
----------------
-- Sub_Second --
----------------
function Sub_Second (Date : Time) return Second_Duration is
Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration;
begin
Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
return Sub_Second;
end Sub_Second;
-------------
-- Time_Of --
-------------
function Time_Of
(Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration := 0.0) return Time
is
Day_Secs : constant Day_Duration :=
Day_Duration (Hour * 3_600) +
Day_Duration (Minute * 60) +
Day_Duration (Second) +
Sub_Second;
begin
return Time_Of (Year, Month, Day, Day_Secs);
end Time_Of;
-----------------------
-- Time_Of_At_Locale --
-----------------------
function Time_Of_At_Locale
(Year : Year_Number;
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration := 0.0) return Time
is
function Ada_Calendar_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 Import (Ada, Ada_Calendar_Time_Of, "__gnat_time_of");
begin
-- Even though the input time zone is UTC (0), the flag Use_TZ will
-- ensure that Split picks up the local time zone. ???But there is no
-- call to Split here.
return
Ada_Calendar_Time_Of
(Year => Year,
Month => Month,
Day => Day,
Day_Secs => 0.0,
Hour => Hour,
Minute => Minute,
Second => Second,
Sub_Sec => Sub_Second,
Leap_Sec => False,
Use_Day_Secs => False,
Use_TZ => False,
Is_Historic => False,
Time_Zone => 0);
end Time_Of_At_Locale;
-----------------
-- To_Duration --
-----------------
function To_Duration (T : not null access timeval) return Duration is
procedure timeval_to_duration
(T : not null access timeval;
sec : not null access C.Extensions.long_long;
usec : not null access C.long);
pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
Micro : constant := 10**6;
sec : aliased C.Extensions.long_long;
usec : aliased C.long;
begin
timeval_to_duration (T, sec'Access, usec'Access);
pragma Annotate (CodePeer, Modified, sec);
pragma Annotate (CodePeer, Modified, usec);
return Duration (sec) + Duration (usec) / Micro;
end To_Duration;
----------------
-- To_Timeval --
----------------
function To_Timeval (D : Duration) return timeval is
procedure duration_to_timeval
(Sec : C.Extensions.long_long;
Usec : C.long;
T : not null access timeval);
pragma Import (C, duration_to_timeval, "__gnat_duration_to_timeval");
Micro : constant := 10**6;
Result : aliased timeval;
sec : C.Extensions.long_long;
usec : C.long;
begin
if D = 0.0 then
sec := 0;
usec := 0;
else
sec := C.Extensions.long_long (D - 0.5);
usec := C.long ((D - Duration (sec)) * Micro - 0.5);
end if;
duration_to_timeval (sec, usec, Result'Access);
return Result;
end To_Timeval;
------------------
-- Week_In_Year --
------------------
function Week_In_Year (Date : Time) return Week_In_Year_Number is
Year : Year_Number;
Week : Week_In_Year_Number;
begin
Year_Week_In_Year (Date, Year, Week);
return Week;
end Week_In_Year;
-----------------------
-- Year_Week_In_Year --
-----------------------
procedure Year_Week_In_Year
(Date : Time;
Year : out Year_Number;
Week : out Week_In_Year_Number)
is
Month : Month_Number;
Day : Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration;
Jan_1 : Day_Name;
Shift : Week_In_Year_Number;
Start_Week : Week_In_Year_Number;
function Is_Leap (Year : Year_Number) return Boolean;
-- Return True if Year denotes a leap year. Leap centennial years are
-- properly handled.
function Jan_1_Day_Of_Week
(Jan_1 : Day_Name;
Year : Year_Number;
Last_Year : Boolean := False;
Next_Year : Boolean := False) return Day_Name;
-- Given the weekday of January 1 in Year, determine the weekday on
-- which January 1 fell last year or will fall next year as set by
-- the two flags. This routine does not call Time_Of or Split.
function Last_Year_Has_53_Weeks
(Jan_1 : Day_Name;
Year : Year_Number) return Boolean;
-- Given the weekday of January 1 in Year, determine whether last year
-- has 53 weeks. A False value implies that the year has 52 weeks.
-------------
-- Is_Leap --
-------------
function Is_Leap (Year : Year_Number) return Boolean is
begin
if Year mod 400 = 0 then
return True;
elsif Year mod 100 = 0 then
return False;
else
return Year mod 4 = 0;
end if;
end Is_Leap;
-----------------------
-- Jan_1_Day_Of_Week --
-----------------------
function Jan_1_Day_Of_Week
(Jan_1 : Day_Name;
Year : Year_Number;
Last_Year : Boolean := False;
Next_Year : Boolean := False) return Day_Name
is
Shift : Integer := 0;
begin
if Last_Year then
Shift := (if Is_Leap (Year - 1) then -2 else -1);
elsif Next_Year then
Shift := (if Is_Leap (Year) then 2 else 1);
end if;
return Day_Name'Val ((Day_Name'Pos (Jan_1) + Shift) mod 7);
end Jan_1_Day_Of_Week;
----------------------------
-- Last_Year_Has_53_Weeks --
----------------------------
function Last_Year_Has_53_Weeks
(Jan_1 : Day_Name;
Year : Year_Number) return Boolean
is
Last_Jan_1 : constant Day_Name :=
Jan_1_Day_Of_Week (Jan_1, Year, Last_Year => True);
begin
-- These two cases are illustrated in the table below
return
Last_Jan_1 = Thursday
or else (Last_Jan_1 = Wednesday and then Is_Leap (Year - 1));
end Last_Year_Has_53_Weeks;
-- Start of processing for Week_In_Year
begin
Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
-- According to ISO 8601, the first week of year Y is the week that
-- contains the first Thursday in year Y. The following table contains
-- all possible combinations of years and weekdays along with examples.
-- +-------+------+-------+---------+
-- | Jan 1 | Leap | Weeks | Example |
-- +-------+------+-------+---------+
-- | Mon | No | 52 | 2007 |
-- +-------+------+-------+---------+
-- | Mon | Yes | 52 | 1996 |
-- +-------+------+-------+---------+
-- | Tue | No | 52 | 2002 |
-- +-------+------+-------+---------+
-- | Tue | Yes | 52 | 1980 |
-- +-------+------+-------+---------+
-- | Wed | No | 52 | 2003 |
-- +-------+------#########---------+
-- | Wed | Yes # 53 # 1992 |
-- +-------+------#-------#---------+
-- | Thu | No # 53 # 1998 |
-- +-------+------#-------#---------+
-- | Thu | Yes # 53 # 2004 |
-- +-------+------#########---------+
-- | Fri | No | 52 | 1999 |
-- +-------+------+-------+---------+
-- | Fri | Yes | 52 | 1988 |
-- +-------+------+-------+---------+
-- | Sat | No | 52 | 1994 |
-- +-------+------+-------+---------+
-- | Sat | Yes | 52 | 1972 |
-- +-------+------+-------+---------+
-- | Sun | No | 52 | 1995 |
-- +-------+------+-------+---------+
-- | Sun | Yes | 52 | 1956 |
-- +-------+------+-------+---------+
-- A small optimization, the input date is January 1. Note that this
-- is a key day since it determines the number of weeks and is used
-- when special casing the first week of January and the last week of
-- December.
Jan_1 := Day_Of_Week (if Day = 1 and then Month = 1
then Date
else (Time_Of (Year, 1, 1, 0.0)));
-- Special cases for January
if Month = 1 then
-- Special case 1: January 1, 2 and 3. These three days may belong
-- to last year's last week which can be week number 52 or 53.
-- +-----+-----+-----+=====+-----+-----+-----+
-- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 26 | 27 | 28 # 29 # 30 | 31 | 1 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 27 | 28 | 29 # 30 # 31 | 1 | 2 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 28 | 29 | 30 # 31 # 1 | 2 | 3 |
-- +-----+-----+-----+=====+-----+-----+-----+
if (Day = 1 and then Jan_1 in Friday .. Sunday)
or else
(Day = 2 and then Jan_1 in Friday .. Saturday)
or else
(Day = 3 and then Jan_1 = Friday)
then
Week := (if Last_Year_Has_53_Weeks (Jan_1, Year) then 53 else 52);
-- January 1, 2 and 3 belong to the previous year
Year := Year - 1;
return;
-- Special case 2: January 1, 2, 3, 4, 5, 6 and 7 of the first week
-- +-----+-----+-----+=====+-----+-----+-----+
-- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 29 | 30 | 31 # 1 # 2 | 3 | 4 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 30 | 31 | 1 # 2 # 3 | 4 | 5 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 31 | 1 | 2 # 3 # 4 | 5 | 6 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 1 | 2 | 3 # 4 # 5 | 6 | 7 |
-- +-----+-----+-----+=====+-----+-----+-----+
elsif (Day <= 4 and then Jan_1 in Monday .. Thursday)
or else
(Day = 5 and then Jan_1 in Monday .. Wednesday)
or else
(Day = 6 and then Jan_1 in Monday .. Tuesday)
or else
(Day = 7 and then Jan_1 = Monday)
then
Week := 1;
return;
end if;
-- Month other than 1
-- Special case 3: December 29, 30 and 31. These days may belong to
-- next year's first week.
-- +-----+-----+-----+=====+-----+-----+-----+
-- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 29 | 30 | 31 # 1 # 2 | 3 | 4 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 30 | 31 | 1 # 2 # 3 | 4 | 5 |
-- +-----+-----+-----+-----+-----+-----+-----+
-- | 31 | 1 | 2 # 3 # 4 | 5 | 6 |
-- +-----+-----+-----+=====+-----+-----+-----+
elsif Month = 12 and then Day > 28 then
declare
Next_Jan_1 : constant Day_Name :=
Jan_1_Day_Of_Week (Jan_1, Year, Next_Year => True);
begin
if (Day = 29 and then Next_Jan_1 = Thursday)
or else
(Day = 30 and then Next_Jan_1 in Wednesday .. Thursday)
or else
(Day = 31 and then Next_Jan_1 in Tuesday .. Thursday)
then
Year := Year + 1;
Week := 1;
return;
end if;
end;
end if;
-- Determine the week from which to start counting. If January 1 does
-- not belong to the first week of the input year, then the next week
-- is the first week.
Start_Week := (if Jan_1 in Friday .. Sunday then 1 else 2);
-- At this point all special combinations have been accounted for and
-- the proper start week has been found. Since January 1 may not fall
-- on a Monday, shift 7 - Day_Name'Pos (Jan_1). This action ensures an
-- origin which falls on Monday.
Shift := 7 - Day_Name'Pos (Jan_1);
Week := Start_Week + (Day_In_Year (Date) - Shift - 1) / 7;
end Year_Week_In_Year;
end GNAT.Calendar;