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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . C A L E N D A R . A R I T H M E T I C --
-- --
-- B o d y --
-- --
-- Copyright (C) 2006, 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- --
-- 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, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- 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. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Unchecked_Conversion;
package body Ada.Calendar.Arithmetic is
use Leap_Sec_Ops;
Day_Duration : constant Duration := 86_400.0;
---------
-- "+" --
---------
function "+" (Left : Time; Right : Day_Count) return Time is
begin
return Left + Integer (Right) * Day_Duration;
end "+";
function "+" (Left : Day_Count; Right : Time) return Time is
begin
return Integer (Left) * Day_Duration + Right;
end "+";
---------
-- "-" --
---------
function "-" (Left : Time; Right : Day_Count) return Time is
begin
return Left - Integer (Right) * Day_Duration;
end "-";
function "-" (Left, Right : Time) return Day_Count is
Days : Day_Count;
Seconds : Duration;
Leap_Seconds : Leap_Seconds_Count;
begin
Difference (Left, Right, Days, Seconds, Leap_Seconds);
return Days;
end "-";
----------------
-- Difference --
----------------
procedure Difference
(Left, Right : Time;
Days : out Day_Count;
Seconds : out Duration;
Leap_Seconds : out Leap_Seconds_Count)
is
Diff : Duration;
Earlier : Time;
Later : Time;
Leaps_Dur : Duration;
Negate : Boolean;
Next_Leap : Time;
Secs_Diff : Long_Integer;
Sub_Seconds : Duration;
begin
if Left >= Right then
Later := Left;
Earlier := Right;
Negate := False;
else
Later := Right;
Earlier := Left;
Negate := True;
end if;
Diff := Later - Earlier;
Cumulative_Leap_Secs (Earlier, Later, Leaps_Dur, Next_Leap);
if Later >= Next_Leap then
Leaps_Dur := Leaps_Dur + 1.0;
end if;
Diff := Diff - Leaps_Dur;
declare
type D_Int is range 0 .. 2 ** (Duration'Size - 1) - 1;
for D_Int'Size use Duration'Size;
Small_Div : constant D_Int := D_Int (1.0 / Duration'Small);
D_As_Int : D_Int;
function To_D_As_Int is new Unchecked_Conversion (Duration, D_Int);
function To_Duration is new Unchecked_Conversion (D_Int, Duration);
begin
D_As_Int := To_D_As_Int (Diff);
Secs_Diff := Long_Integer (D_As_Int / Small_Div);
Sub_Seconds := To_Duration (D_As_Int rem Small_Div);
end;
Days := Day_Count (Secs_Diff / 86_400);
Seconds := Duration (Secs_Diff mod 86_400) + Sub_Seconds;
Leap_Seconds := Leap_Seconds_Count (Leaps_Dur);
if Negate then
Days := -Days;
Seconds := -Seconds;
Leap_Seconds := -Leap_Seconds;
end if;
end Difference;
end Ada.Calendar.Arithmetic;
|
