gcc/ada/g-calend.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                         G N A T . C A L E N D A R                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1999-2007, Free Software Foundation, Inc.         --
  10 --                                                                          --
  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- --
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  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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  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.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package extends Ada.Calendar to handle Hour, Minute, Second,
  35 --  Second_Duration and Day_Of_Week and Day_In_Year from Calendar.Time.
  36 --  Second_Duration precision depends on the target clock precision.
  37 --
  38 --  GNAT.Calendar provides the same kind of abstraction found in
  39 --  Ada.Calendar. It provides Split and Time_Of to build and split a Time
  40 --  data. And it provides accessor functions to get only one of Hour, Minute,
  41 --  Second, Second_Duration. Other functions are to access more advanced
  42 --  values like Day_Of_Week, Day_In_Year and Week_In_Year.
  43
  44 with Ada.Calendar;
  45 with Interfaces.C;
  46
  47 package GNAT.Calendar is
  48
  49    type Day_Name is
  50      (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday);
  51
  52    subtype Hour_Number         is Natural range 0 .. 23;
  53    subtype Minute_Number       is Natural range 0 .. 59;
  54    subtype Second_Number       is Natural range 0 .. 59;
  55    subtype Second_Duration     is Ada.Calendar.Day_Duration range 0.0 .. 1.0;
  56    subtype Day_In_Year_Number  is Positive range 1 .. 366;
  57    subtype Week_In_Year_Number is Positive range 1 .. 53;
  58
  59    No_Time : constant Ada.Calendar.Time;
  60    --  A constant set to the first date that can be represented by the type
  61    --  Time. It can be used to indicate an uninitialized date.
  62
  63    function Hour       (Date : Ada.Calendar.Time) return Hour_Number;
  64    function Minute     (Date : Ada.Calendar.Time) return Minute_Number;
  65    function Second     (Date : Ada.Calendar.Time) return Second_Number;
  66    function Sub_Second (Date : Ada.Calendar.Time) return Second_Duration;
  67    --  Hour, Minute, Second and Sub_Second returns the complete time data for
  68    --  the Date (H:M:S.SS). See Ada.Calendar for Year, Month, Day accessors.
  69    --  Second_Duration precision depends on the target clock precision.
  70
  71    function Day_Of_Week (Date : Ada.Calendar.Time) return Day_Name;
  72    --  Return the day name
  73
  74    function Day_In_Year (Date : Ada.Calendar.Time) return Day_In_Year_Number;
  75    --  Returns the day number in the year. (1st January is day 1 and 31st
  76    --  December is day 365 or 366 for leap year).
  77
  78    function Week_In_Year (Date : Ada.Calendar.Time) return Week_In_Year_Number;
  79    --  Returns the week number as defined in ISO 8601. A week always starts on
  80    --  a Monday and the first week of a particular year is the one containing
  81    --  the first Thursday. A year may have 53 weeks when January 1st is a
  82    --  Wednesday and the year is leap or January 1st is a Thursday. Note that
  83    --  the last days of December may belong to the first week on the next year
  84    --  and conversely, the first days of January may belong to the last week
  85    --  of the last year.
  86
  87    procedure Split
  88      (Date       : Ada.Calendar.Time;
  89       Year       : out Ada.Calendar.Year_Number;
  90       Month      : out Ada.Calendar.Month_Number;
  91       Day        : out Ada.Calendar.Day_Number;
  92       Hour       : out Hour_Number;
  93       Minute     : out Minute_Number;
  94       Second     : out Second_Number;
  95       Sub_Second : out Second_Duration);
  96    --  Split the standard Ada.Calendar.Time data in date data (Year, Month,
  97    --  Day) and Time data (Hour, Minute, Second, Sub_Second)
  98
  99    function Time_Of
 100      (Year       : Ada.Calendar.Year_Number;
 101       Month      : Ada.Calendar.Month_Number;
 102       Day        : Ada.Calendar.Day_Number;
 103       Hour       : Hour_Number;
 104       Minute     : Minute_Number;
 105       Second     : Second_Number;
 106       Sub_Second : Second_Duration := 0.0) return Ada.Calendar.Time;
 107    --  Returns an Ada.Calendar.Time data built from the date and time values
 108
 109    --  C timeval conversion
 110
 111    --  C timeval represent a duration (used in Select for example). This
 112    --  structure is composed of a number of seconds and a number of micro
 113    --  seconds. The timeval structure is not exposed here because its
 114    --  definition is target dependent. Interface to C programs is done via a
 115    --  pointer to timeval structure.
 116
 117    type timeval is private;
 118
 119    function To_Duration (T : not null access timeval) return Duration;
 120    function To_Timeval  (D : Duration) return timeval;
 121
 122 private
 123    --  This is a dummy declaration that should be the largest possible timeval
 124    --  structure of all supported targets.
 125
 126    type timeval is array (1 .. 2) of Interfaces.C.long;
 127
 128    function Julian_Day
 129      (Year  : Ada.Calendar.Year_Number;
 130       Month : Ada.Calendar.Month_Number;
 131       Day   : Ada.Calendar.Day_Number) return Integer;
 132    --  Compute Julian day number
 133    --
 134    --  The code of this function is a modified version of algorithm 199 from
 135    --  the Collected Algorithms of the ACM. The author of algorithm 199 is
 136    --  Robert G. Tantzen.
 137
 138    No_Time : constant Ada.Calendar.Time :=
 139                Ada.Calendar.Time_Of
 140                  (Ada.Calendar.Year_Number'First,
 141                   Ada.Calendar.Month_Number'First,
 142                   Ada.Calendar.Day_Number'First);
 143
 144 end GNAT.Calendar;