1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . C A L E N D A R --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
11 -- This specification is derived from the Ada Reference Manual for use with --
12 -- GNAT. The copyright notice above, and the license provisions that follow --
13 -- apply solely to the contents of the part following the private keyword. --
15 -- GNAT is free software; you can redistribute it and/or modify it under --
16 -- terms of the GNU General Public License as published by the Free Soft- --
17 -- ware Foundation; either version 2, or (at your option) any later ver- --
18 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
19 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
20 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
21 -- for more details. You should have received a copy of the GNU General --
22 -- Public License distributed with GNAT; see file COPYING. If not, write --
23 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
24 -- Boston, MA 02110-1301, USA. --
26 -- As a special exception, if other files instantiate generics from this --
27 -- unit, or you link this unit with other files to produce an executable, --
28 -- this unit does not by itself cause the resulting executable to be --
29 -- covered by the GNU General Public License. This exception does not --
30 -- however invalidate any other reasons why the executable file might be --
31 -- covered by the GNU Public License. --
33 -- GNAT was originally developed by the GNAT team at New York University. --
34 -- Extensive contributions were provided by Ada Core Technologies Inc. --
36 ------------------------------------------------------------------------------
38 -- This is the Alpha/VMS version
40 with System.OS_Primitives;
41 package Ada.Calendar is
43 package OSP renames System.OS_Primitives;
47 -- Declarations representing limits of allowed local time values. Note
48 -- that these do NOT constrain the possible stored values of time which
49 -- may well permit a larger range of times (this is explicitly allowed
52 subtype Year_Number is Integer range 1901 .. 2399;
53 subtype Month_Number is Integer range 1 .. 12;
54 subtype Day_Number is Integer range 1 .. 31;
56 subtype Day_Duration is Duration range 0.0 .. 86_400.0;
58 function Clock return Time;
60 function Year (Date : Time) return Year_Number;
61 function Month (Date : Time) return Month_Number;
62 function Day (Date : Time) return Day_Number;
63 function Seconds (Date : Time) return Day_Duration;
67 Year : out Year_Number;
68 Month : out Month_Number;
70 Seconds : out Day_Duration);
76 Seconds : Day_Duration := 0.0) return Time;
78 function "+" (Left : Time; Right : Duration) return Time;
79 function "+" (Left : Duration; Right : Time) return Time;
80 function "-" (Left : Time; Right : Duration) return Time;
81 function "-" (Left : Time; Right : Time) return Duration;
83 function "<" (Left, Right : Time) return Boolean;
84 function "<=" (Left, Right : Time) return Boolean;
85 function ">" (Left, Right : Time) return Boolean;
86 function ">=" (Left, Right : Time) return Boolean;
88 Time_Error : exception;
91 pragma Inline (Clock);
94 pragma Inline (Month);
101 pragma Inline ("<=");
103 pragma Inline (">=");
105 -- Although the units are 100 nanoseconds, for the purpose of better
106 -- readability, this unit will be called "mili".
108 Mili : constant := 10_000_000;
109 Milis_In_Day : constant := 864_000_000_000;
110 Secs_In_Day : constant := 86_400;
112 -- Time is represented as the number of 100-nanosecond (ns) units from the
113 -- system base date and time 1858-11-17 0.0 (the Smithsonian base date and
114 -- time for the astronomic calendar).
116 -- The time value stored is typically a UTC value, as provided in standard
117 -- Unix environments. If this is the case then Split and Time_Of perform
118 -- required conversions to and from local times.
120 -- Notwithstanding this definition, Time is not quite the same as OS_Time.
121 -- Relative Time is positive, whereas relative OS_Time is negative,
122 -- but this declaration makes for easier conversion.
124 type Time is new OSP.OS_Time;
126 Days_In_Month : constant array (Month_Number) of Day_Number :=
127 (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
129 Invalid_Time_Zone_Offset : Long_Integer;
130 pragma Import (C, Invalid_Time_Zone_Offset, "__gnat_invalid_tzoff");
132 function Is_Leap (Year : Year_Number) return Boolean;
133 -- Determine whether a given year is leap
135 -- The following packages provide a target independent interface to the
136 -- children of Calendar - Arithmetic, Formatting and Time_Zones.
138 -- NOTE: Delays does not need a target independent interface because
139 -- VMS already has a target specific file for that package.
141 package Arithmetic_Operations is
142 function Add (Date : Time; Days : Long_Integer) return Time;
143 -- Add a certain number of days to a time value
148 Days : out Long_Integer;
149 Seconds : out Duration;
150 Leap_Seconds : out Integer);
151 -- Calculate the difference between two time values in terms of days,
152 -- seconds and leap seconds elapsed. The leap seconds are not included
153 -- in the seconds returned. If Left is greater than Right, the returned
154 -- values are positive, negative otherwise.
156 function Subtract (Date : Time; Days : Long_Integer) return Time;
157 -- Subtract a certain number of days from a time value
158 end Arithmetic_Operations;
160 package Formatting_Operations is
161 function Day_Of_Week (Date : Time) return Integer;
162 -- Determine which day of week Date falls on. The returned values are
163 -- within the range of 0 .. 6 (Monday .. Sunday).
167 Year : out Year_Number;
168 Month : out Month_Number;
169 Day : out Day_Number;
170 Day_Secs : out Day_Duration;
172 Minute : out Integer;
173 Second : out Integer;
174 Sub_Sec : out Duration;
175 Leap_Sec : out Boolean;
177 Time_Zone : Long_Integer);
178 -- Split a time value into its components. Set Is_Ada_05 to use the
179 -- local time zone (the value in Time_Zone is ignored) when splitting
184 Month : Month_Number;
186 Day_Secs : Day_Duration;
192 Use_Day_Secs : Boolean;
194 Time_Zone : Long_Integer) return Time;
195 -- Given all the components of a date, return the corresponding time
196 -- value. Set Use_Day_Secs to use the value in Day_Secs, otherwise the
197 -- day duration will be calculated from Hour, Minute, Second and Sub_
198 -- Sec. Set Is_Ada_05 to use the local time zone (the value in formal
199 -- Time_Zone is ignored) when building a time value and to verify the
200 -- validity of a requested leap second.
201 end Formatting_Operations;
203 package Time_Zones_Operations is
204 function UTC_Time_Offset (Date : Time) return Long_Integer;
205 -- Return the offset in seconds from UTC
206 end Time_Zones_Operations;