gcc/ada/a-calend-vms.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                         A D A . C A L E N D A R                          --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2006, Free Software Foundation, Inc.         --
  10 --                                                                          --
  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. --
  14 --                                                                          --
  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.                                              --
  25 --                                                                          --
  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.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 --  This is the Alpha/VMS version
  39
  40 with System.OS_Primitives;
  41 package Ada.Calendar is
  42
  43    package OSP renames System.OS_Primitives;
  44
  45    type Time is private;
  46
  47    --  Declarations representing limits of allowed local time values. Note that
  48    --  these do NOT constrain the possible stored values of time which may well
  49    --  permit a larger range of times (this is explicitly allowed in Ada 95).
  50
  51    subtype Year_Number  is Integer range 1901 .. 2099;
  52    subtype Month_Number is Integer range 1 .. 12;
  53    subtype Day_Number   is Integer range 1 .. 31;
  54
  55    subtype Day_Duration is Duration range 0.0 .. 86_400.0;
  56
  57    function Clock return Time;
  58
  59    function Year    (Date : Time) return Year_Number;
  60    function Month   (Date : Time) return Month_Number;
  61    function Day     (Date : Time) return Day_Number;
  62    function Seconds (Date : Time) return Day_Duration;
  63
  64    procedure Split
  65      (Date    : Time;
  66       Year    : out Year_Number;
  67       Month   : out Month_Number;
  68       Day     : out Day_Number;
  69       Seconds : out Day_Duration);
  70
  71    function Time_Of
  72      (Year    : Year_Number;
  73       Month   : Month_Number;
  74       Day     : Day_Number;
  75       Seconds : Day_Duration := 0.0)
  76       return    Time;
  77
  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;
  82
  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;
  87
  88    Time_Error : exception;
  89
  90    Unimplemented : exception;
  91
  92 private
  93
  94    pragma Inline (Clock);
  95
  96    pragma Inline (Year);
  97    pragma Inline (Month);
  98    pragma Inline (Day);
  99
 100    pragma Inline ("+");
 101    pragma Inline ("-");
 102
 103    pragma Inline ("<");
 104    pragma Inline ("<=");
 105    pragma Inline (">");
 106    pragma Inline (">=");
 107
 108    --  Time is represented as the number of 100-nanosecond (ns) units offset
 109    --  from the system base date and time, which is 00:00 o'clock,
 110    --  November 17, 1858 (the Smithsonian base date and time for the
 111    --  astronomic calendar).
 112
 113    --  The time value stored is typically a GMT value, as provided in standard
 114    --  Unix environments. If this is the case then Split and Time_Of perform
 115    --  required conversions to and from local times.
 116
 117    type Time is new OSP.OS_Time;
 118
 119    --  Notwithstanding this definition, Time is not quite the same as OS_Time.
 120    --  Relative Time is positive, whereas relative OS_Time is negative,
 121    --  but this declaration makes for easier conversion.
 122
 123    --  The following package provides handling of leap seconds. It is
 124    --  used by Ada.Calendar.Arithmetic and Ada.Calendar.Formatting, both
 125    --  Ada 2005 children of Ada.Calendar.
 126
 127    package Leap_Sec_Ops is
 128
 129       After_Last_Leap : constant Time := Time'Last;
 130       --  Bigger by far than any leap second value. Not within range of
 131       --  Ada.Calendar specified dates.
 132
 133       procedure Cumulative_Leap_Secs
 134         (Start_Date    : Time;
 135          End_Date      : Time;
 136          Leaps_Between : out Duration;
 137          Next_Leap_Sec : out Time);
 138       --  Leaps_Between is the sum of the leap seconds that have occured
 139       --  on or after Start_Date and before (strictly before) End_Date.
 140       --  Next_Leap_Sec represents the next leap second occurence on or
 141       --  after End_Date. If there are no leaps seconds after End_Date,
 142       --  After_Last_Leap is returned. This does not provide info about
 143       --  the next leap second (pos/neg or ?). After_Last_Leap can be used
 144       --  as End_Date to count all the leap seconds that have occured on
 145       --  or after Start_Date.
 146       --
 147       --  Important Notes: any fractional parts of Start_Date and End_Date
 148       --  are discarded before the calculations are done. For instance: if
 149       --  113 seconds is a leap second (it isn't) and 113.5 is input as an
 150       --  End_Date, the leap second at 113 will not be counted in
 151       --  Leaps_Between, but it will be returned as Next_Leap_Sec. Thus, if
 152       --  the caller wants to know if the End_Date is a leap second, the
 153       --  comparison should be:
 154       --
 155       --     End_Date >= Next_Leap_Sec;
 156       --
 157       --  After_Last_Leap is designed so that this comparison works without
 158       --  having to first check if Next_Leap_Sec is a valid leap second.
 159
 160       function All_Leap_Seconds return Duration;
 161       --  Returns the sum off all of the leap seoncds.
 162
 163    end Leap_Sec_Ops;
 164
 165    procedure Split_With_Offset
 166      (Date    : Time;
 167       Year    : out Year_Number;
 168       Month   : out Month_Number;
 169       Day     : out Day_Number;
 170       Seconds : out Day_Duration;
 171       Offset  : out Long_Integer);
 172    --  Split_W_Offset has the same spec as Split with the addition of an
 173    --  offset value which give the offset of the local time zone from UTC
 174    --  at the input Date. This value comes for free during the implementation
 175    --  of Split and is needed by UTC_Time_Offset. The returned Offset time
 176    --  is straight from the C tm struct and is in seconds. If the system
 177    --  dependent code has no way to find the offset it will return the value
 178    --  Invalid_TZ_Offset declared below. Otherwise no checking is done, so
 179    --  it is up to the user to check both for Invalid_TZ_Offset and otherwise
 180    --  for a value that is acceptable.
 181
 182    Invalid_TZ_Offset : Long_Integer;
 183    pragma Import (C, Invalid_TZ_Offset, "__gnat_invalid_tzoff");
 184
 185 end Ada.Calendar;