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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                         G N A T . C A L E N D A R                        --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--                     Copyright (C) 1999-2005, AdaCore                     --

--                                                                          --

-- 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,  51  Franklin  Street,  Fifth  Floor, --

-- Boston, MA 02110-1301, 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.      --

--                                                                          --

------------------------------------------------------------------------------

package body GNAT.Calendar is

   use Ada.Calendar;

   use Interfaces;

   -----------------

   -- Day_In_Year --

   -----------------

   function Day_In_Year (Date : Time) return Day_In_Year_Number is

      Year  : Year_Number;

      Month : Month_Number;

      Day   : Day_Number;

      Dsecs : Day_Duration;

   begin

      Split (Date, Year, Month, Day, Dsecs);

      return Julian_Day (Year, Month, Day) - Julian_Day (Year, 1, 1) + 1;

   end Day_In_Year;

   -----------------

   -- Day_Of_Week --

   -----------------

   function Day_Of_Week (Date : Time) return Day_Name is

      Year  : Year_Number;

      Month : Month_Number;

      Day   : Day_Number;

      Dsecs : Day_Duration;

   begin

      Split (Date, Year, Month, Day, Dsecs);

      return Day_Name'Val ((Julian_Day (Year, Month, Day)) mod 7);

   end Day_Of_Week;

   ----------

   -- Hour --

   ----------

   function Hour (Date : Time) return Hour_Number is

      Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration;

   begin

      Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);

      return Hour;

   end Hour;

   ----------------

   -- Julian_Day --

   ----------------

   --  Julian_Day is used to by Day_Of_Week and Day_In_Year. Note

   --  that this implementation is not expensive.

   function Julian_Day

     (Year  : Year_Number;

      Month : Month_Number;

      Day   : Day_Number) return Integer

   is

      Internal_Year  : Integer;

      Internal_Month : Integer;

      Internal_Day   : Integer;

      Julian_Date    : Integer;

      C              : Integer;

      Ya             : Integer;

   begin

      Internal_Year  := Integer (Year);

      Internal_Month := Integer (Month);

      Internal_Day   := Integer (Day);

      if Internal_Month > 2 then

         Internal_Month := Internal_Month - 3;

      else

         Internal_Month := Internal_Month + 9;

         Internal_Year  := Internal_Year - 1;

      end if;

      C  := Internal_Year / 100;

      Ya := Internal_Year - (100 * C);

      Julian_Date := (146_097 * C) / 4 +

        (1_461 * Ya) / 4 +

        (153 * Internal_Month + 2) / 5 +

        Internal_Day + 1_721_119;

      return Julian_Date;

   end Julian_Day;

   ------------

   -- Minute --

   ------------

   function Minute (Date : Time) return Minute_Number is

      Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration;

   begin

      Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);

      return Minute;

   end Minute;

   ------------

   -- Second --

   ------------

   function Second (Date : Time) return Second_Number is

      Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration;

   begin

      Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);

      return Second;

   end Second;

   -----------

   -- Split --

   -----------

   procedure Split

     (Date       : Time;

      Year       : out Year_Number;

      Month      : out Month_Number;

      Day        : out Day_Number;

      Hour       : out Hour_Number;

      Minute     : out Minute_Number;

      Second     : out Second_Number;

      Sub_Second : out Second_Duration)

   is

      Dsecs : Day_Duration;

      Secs  : Natural;

   begin

      Split (Date, Year, Month, Day, Dsecs);

      if Dsecs = 0.0 then

         Secs := 0;

      else

         Secs := Natural (Dsecs - 0.5);

      end if;

      Sub_Second := Second_Duration (Dsecs - Day_Duration (Secs));

      Hour       := Hour_Number (Secs / 3600);

      Secs       := Secs mod 3600;

      Minute     := Minute_Number (Secs / 60);

      Second     := Second_Number (Secs mod 60);

   end Split;

   ----------------

   -- Sub_Second --

   ----------------

   function Sub_Second (Date : Time) return Second_Duration is

      Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration;

   begin

      Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);

      return Sub_Second;

   end Sub_Second;

   -------------

   -- Time_Of --

   -------------

   function Time_Of

     (Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration := 0.0) return Time

   is

      Dsecs : constant Day_Duration :=

                Day_Duration (Hour * 3600 + Minute * 60 + Second) +

                                                             Sub_Second;

   begin

      return Time_Of (Year, Month, Day, Dsecs);

   end Time_Of;

   -----------------

   -- To_Duration --

   -----------------

   function To_Duration (T : access timeval) return Duration is

      procedure timeval_to_duration

        (T    : access timeval;

         sec  : access C.long;

         usec : access C.long);

      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");

      Micro : constant := 10**6;

      sec   : aliased C.long;

      usec  : aliased C.long;

   begin

      timeval_to_duration (T, sec'Access, usec'Access);

      return Duration (sec) + Duration (usec) / Micro;

   end To_Duration;

   ----------------

   -- To_Timeval --

   ----------------

   function To_Timeval  (D : Duration) return timeval is

      procedure duration_to_timeval (Sec, Usec : C.long; T : access timeval);

      pragma Import (C, duration_to_timeval, "__gnat_duration_to_timeval");

      Micro  : constant := 10**6;

      Result : aliased timeval;

      sec    : C.long;

      usec   : C.long;

   begin

      if D = 0.0 then

         sec  := 0;

         usec := 0;

      else

         sec  := C.long (D - 0.5);

         usec := C.long ((D - Duration (sec)) * Micro - 0.5);

      end if;

      duration_to_timeval (sec, usec, Result'Access);

      return Result;

   end To_Timeval;

   ------------------

   -- Week_In_Year --

   ------------------

   function Week_In_Year

     (Date : Ada.Calendar.Time) return Week_In_Year_Number

   is

      Year       : Year_Number;

      Month      : Month_Number;

      Day        : Day_Number;

      Hour       : Hour_Number;

      Minute     : Minute_Number;

      Second     : Second_Number;

      Sub_Second : Second_Duration;

      Offset     : Natural;

   begin

      Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);

      --  Day offset number for the first week of the year

      Offset := Julian_Day (Year, 1, 1) mod 7;

      return 1 + ((Day_In_Year (Date) - 1) + Offset) / 7;

   end Week_In_Year;

end GNAT.Calendar;