gcc/ada/a-calend.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 package Ada.Calendar is
  39
  40    type Time is private;
  41
  42    --  Declarations representing limits of allowed local time values. Note that
  43    --  these do NOT constrain the possible stored values of time which may well
  44    --  permit a larger range of times (this is explicitly allowed in Ada 95).
  45
  46    subtype Year_Number  is Integer range 1901 .. 2099;
  47    subtype Month_Number is Integer range 1 .. 12;
  48    subtype Day_Number   is Integer range 1 .. 31;
  49
  50    subtype Day_Duration is Duration range 0.0 .. 86_400.0;
  51
  52    function Clock return Time;
  53
  54    function Year    (Date : Time) return Year_Number;
  55    function Month   (Date : Time) return Month_Number;
  56    function Day     (Date : Time) return Day_Number;
  57    function Seconds (Date : Time) return Day_Duration;
  58
  59    procedure Split
  60      (Date    : Time;
  61       Year    : out Year_Number;
  62       Month   : out Month_Number;
  63       Day     : out Day_Number;
  64       Seconds : out Day_Duration);
  65
  66    function Time_Of
  67      (Year    : Year_Number;
  68       Month   : Month_Number;
  69       Day     : Day_Number;
  70       Seconds : Day_Duration := 0.0) return Time;
  71    --  GNAT Note: Normally when procedure Split is called on a Time value
  72    --  result of a call to function Time_Of, the out parameters of procedure
  73    --  Split are identical to the in parameters of function Time_Of. However,
  74    --  when a non-existent time of day is specified, the values for Seconds
  75    --  may or may not be different. This may happen when Daylight Saving Time
  76    --  (DST) is in effect, on the day when switching to DST, if Seconds
  77    --  specifies a time of day in the hour that does not exist. For example,
  78    --  in New York:
  79    --
  80    --    Time_Of (Year => 1998, Month => 4, Day => 5, Seconds => 10740.0)
  81    --
  82    --  will return a Time value T. If Split is called on T, the resulting
  83    --  Seconds may be 14340.0 (3:59:00) instead of 10740.0 (2:59:00 being
  84    --  a time that not exist).
  85
  86    function "+" (Left : Time;     Right : Duration) return Time;
  87    function "+" (Left : Duration; Right : Time)     return Time;
  88    function "-" (Left : Time;     Right : Duration) return Time;
  89    function "-" (Left : Time;     Right : Time)     return Duration;
  90
  91    function "<"  (Left, Right : Time) return Boolean;
  92    function "<=" (Left, Right : Time) return Boolean;
  93    function ">"  (Left, Right : Time) return Boolean;
  94    function ">=" (Left, Right : Time) return Boolean;
  95
  96    Time_Error : exception;
  97
  98 private
  99    pragma Inline (Clock);
 100
 101    pragma Inline (Year);
 102    pragma Inline (Month);
 103    pragma Inline (Day);
 104
 105    pragma Inline ("+");
 106    pragma Inline ("-");
 107
 108    pragma Inline ("<");
 109    pragma Inline ("<=");
 110    pragma Inline (">");
 111    pragma Inline (">=");
 112
 113    --  Time is represented as a signed duration from the base point which is
 114    --  what Unix calls the EPOCH (i.e. 12 midnight (24:00:00), Dec 31st, 1969,
 115    --  or if you prefer 0:00:00 on Jan 1st, 1970). Since Ada allows dates
 116    --  before this EPOCH value, the stored duration value may be negative.
 117
 118    --  The time value stored is typically a GMT value, as provided in standard
 119    --  Unix environments. If this is the case then Split and Time_Of perform
 120    --  required conversions to and from local times. The range of times that
 121    --  can be stored in Time values depends on the declaration of the type
 122    --  Duration, which must at least cover the required Ada range represented
 123    --  by the declaration of Year_Number, but may be larger (we take full
 124    --  advantage of the new permission in Ada 95 to store time values outside
 125    --  the range that would be acceptable to Split). The Duration type is a
 126    --  real value representing a time interval in seconds.
 127
 128    type Time is new Duration;
 129
 130    --  The following package provides handling of leap seconds. It is
 131    --  used by Ada.Calendar.Arithmetic and Ada.Calendar.Formatting, both
 132    --  Ada 2005 children of Ada.Calendar.
 133
 134    package Leap_Sec_Ops is
 135
 136       After_Last_Leap : constant Time := Time'Last;
 137       --  Bigger by far than any leap second value. Not within range of
 138       --  Ada.Calendar specified dates.
 139
 140       procedure Cumulative_Leap_Secs
 141         (Start_Date    : Time;
 142          End_Date      : Time;
 143          Leaps_Between : out Duration;
 144          Next_Leap_Sec : out Time);
 145       --  Leaps_Between is the sum of the leap seconds that have occured
 146       --  on or after Start_Date and before (strictly before) End_Date.
 147       --  Next_Leap_Sec represents the next leap second occurence on or
 148       --  after End_Date. If there are no leaps seconds after End_Date,
 149       --  After_Last_Leap is returned. This does not provide info about
 150       --  the next leap second (pos/neg or ?). After_Last_Leap can be used
 151       --  as End_Date to count all the leap seconds that have occured on
 152       --  or after Start_Date.
 153       --
 154       --  Important Notes: any fractional parts of Start_Date and End_Date
 155       --  are discarded before the calculations are done. For instance: if
 156       --  113 seconds is a leap second (it isn't) and 113.5 is input as an
 157       --  End_Date, the leap second at 113 will not be counted in
 158       --  Leaps_Between, but it will be returned as Next_Leap_Sec. Thus, if
 159       --  the caller wants to know if the End_Date is a leap second, the
 160       --  comparison should be:
 161       --
 162       --     End_Date >= Next_Leap_Sec;
 163       --
 164       --  After_Last_Leap is designed so that this comparison works without
 165       --  having to first check if Next_Leap_Sec is a valid leap second.
 166
 167       function All_Leap_Seconds return Duration;
 168       --  Returns the sum off all of the leap seoncds.
 169
 170    end Leap_Sec_Ops;
 171
 172    procedure Split_With_Offset
 173      (Date    : Time;
 174       Year    : out Year_Number;
 175       Month   : out Month_Number;
 176       Day     : out Day_Number;
 177       Seconds : out Day_Duration;
 178       Offset  : out Long_Integer);
 179    --  Split_W_Offset has the same spec as Split with the addition of an
 180    --  offset value which give the offset of the local time zone from UTC
 181    --  at the input Date. This value comes for free during the implementation
 182    --  of Split and is needed by UTC_Time_Offset. The returned Offset time
 183    --  is straight from the C tm struct and is in seconds. If the system
 184    --  dependent code has no way to find the offset it will return the value
 185    --  Invalid_TZ_Offset declared below. Otherwise no checking is done, so
 186    --  it is up to the user to check both for Invalid_TZ_Offset and otherwise
 187    --  for a value that is acceptable.
 188
 189    Invalid_TZ_Offset : Long_Integer;
 190    pragma Import (C, Invalid_TZ_Offset, "__gnat_invalid_tzoff");
 191
 192 end Ada.Calendar;