1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . C A L E N D A R . A R I T H M E T I C --
9 -- Copyright (C) 2006, 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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Unchecked_Conversion
;
36 package body Ada
.Calendar
.Arithmetic
is
40 Day_Duration
: constant Duration := 86_400
.0
;
46 function "+" (Left
: Time
; Right
: Day_Count
) return Time
is
48 return Left
+ Integer (Right
) * Day_Duration
;
51 function "+" (Left
: Day_Count
; Right
: Time
) return Time
is
53 return Integer (Left
) * Day_Duration
+ Right
;
60 function "-" (Left
: Time
; Right
: Day_Count
) return Time
is
62 return Left
- Integer (Right
) * Day_Duration
;
65 function "-" (Left
, Right
: Time
) return Day_Count
is
68 Leap_Seconds
: Leap_Seconds_Count
;
71 Difference
(Left
, Right
, Days
, Seconds
, Leap_Seconds
);
82 Seconds
: out Duration;
83 Leap_Seconds
: out Leap_Seconds_Count
)
91 Secs_Diff
: Long_Integer;
92 Sub_Seconds
: Duration;
105 Diff
:= Later
- Earlier
;
107 Cumulative_Leap_Secs
(Earlier
, Later
, Leaps_Dur
, Next_Leap
);
109 if Later
>= Next_Leap
then
110 Leaps_Dur
:= Leaps_Dur
+ 1.0;
113 Diff
:= Diff
- Leaps_Dur
;
116 type D_Int
is range 0 .. 2 ** (Duration'Size - 1) - 1;
117 for D_Int
'Size use Duration'Size;
119 Small_Div
: constant D_Int
:= D_Int
(1.0 / Duration'Small);
122 function To_D_As_Int
is new Unchecked_Conversion
(Duration, D_Int
);
123 function To_Duration
is new Unchecked_Conversion
(D_Int
, Duration);
126 D_As_Int
:= To_D_As_Int
(Diff
);
127 Secs_Diff
:= Long_Integer (D_As_Int
/ Small_Div
);
128 Sub_Seconds
:= To_Duration
(D_As_Int
rem Small_Div
);
131 Days
:= Day_Count
(Secs_Diff
/ 86_400
);
132 Seconds
:= Duration (Secs_Diff
mod 86_400
) + Sub_Seconds
;
133 Leap_Seconds
:= Leap_Seconds_Count
(Leaps_Dur
);
138 Leap_Seconds
:= -Leap_Seconds
;
142 end Ada
.Calendar
.Arithmetic
;