------------------------------------------------------------------------------ -- -- -- 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 -- -- -- -- S p e c -- -- -- -- Copyright (C) 2005-2006, 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 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. -- -- -- ------------------------------------------------------------------------------ -- This package provides arithmetic operations of time values using days -- and leap seconds. Ada.Calendar.Arithmetic is defined in the Ada 2005 -- RM (9.6.1). package Ada.Calendar.Arithmetic is -- Arithmetic on days: -- Rough estimate on the number of days over the range of Ada time type Day_Count is range -(366 * (1 + Year_Number'Last - Year_Number'First)) .. +(366 * (1 + Year_Number'Last - Year_Number'First)); -- Negative leap seconds occur whenever the astronomical time is faster -- than the atomic time or as a result of Difference when Left < Right. subtype Leap_Seconds_Count is Integer range -2047 .. 2047; procedure Difference (Left : Time; Right : Time; Days : out Day_Count; Seconds : out Duration; Leap_Seconds : out Leap_Seconds_Count); -- Returns the difference between Left and Right. Days is the number of -- days of difference, Seconds is the remainder seconds of difference -- excluding leap seconds, and Leap_Seconds is the number of leap seconds. -- If Left < Right, then Seconds <= 0.0, Days <= 0, and Leap_Seconds <= 0, -- otherwise all values are nonnegative. The absolute value of Seconds is -- always less than 86_400.0. For the returned values, if Days = 0, then -- Seconds + Duration (Leap_Seconds) = Calendar."-" (Left, Right) function "+" (Left : Time; Right : Day_Count) return Time; function "+" (Left : Day_Count; Right : Time) return Time; -- Adds a number of days to a time value. Time_Error is raised if the -- result is not representable as a value of type Time. function "-" (Left : Time; Right : Day_Count) return Time; -- Subtracts a number of days from a time value. Time_Error is raised if -- the result is not representable as a value of type Time. function "-" (Left : Time; Right : Time) return Day_Count; -- Subtracts two time values, and returns the number of days between them. -- This is the same value that Difference would return in Days. end Ada.Calendar.Arithmetic;