------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- G N A T . C A L E N D A R --
-- --
-- S p e c --
-- --
-- Copyright (C) 1999-2016, Free Software Foundation, Inc. --
-- --
-- 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 3, 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- In particular, you can freely distribute your programs built with the --
-- GNAT Pro compiler, including any required library run-time units, using --
-- any licensing terms of your choosing. See the AdaCore Software License --
-- for full details. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package extends Ada.Calendar to handle Hour, Minute, Second,
-- Second_Duration and Day_Of_Week and Day_In_Year from Calendar.Time.
-- Second_Duration precision depends on the target clock precision.
--
-- GNAT.Calendar provides the same kind of abstraction found in Ada.Calendar.
-- It provides Split and Time_Of to build and split a Time data. And it
-- provides accessor functions to get only one of Hour, Minute, Second,
-- Second_Duration. Other functions are to access more advanced values like
-- Day_Of_Week, Day_In_Year and Week_In_Year.
with Ada.Calendar.Formatting;
with Interfaces.C;
package GNAT.Calendar is
type Day_Name is
(Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday);
pragma Ordered (Day_Name);
subtype Hour_Number is Natural range 0 .. 23;
subtype Minute_Number is Natural range 0 .. 59;
subtype Second_Number is Natural range 0 .. 59;
subtype Second_Duration is Ada.Calendar.Day_Duration range 0.0 .. 1.0;
subtype Day_In_Year_Number is Positive range 1 .. 366;
subtype Week_In_Year_Number is Positive range 1 .. 53;
No_Time : constant Ada.Calendar.Time;
-- A constant set to the first date that can be represented by the type
-- Time. It can be used to indicate an uninitialized date.
function Hour (Date : Ada.Calendar.Time) return Hour_Number;
function Minute (Date : Ada.Calendar.Time) return Minute_Number;
function Second (Date : Ada.Calendar.Time) return Second_Number;
function Sub_Second (Date : Ada.Calendar.Time) return Second_Duration;
-- Hour, Minute, Second and Sub_Second returns the complete time data for
-- the Date (H:M:S.SS). See Ada.Calendar for Year, Month, Day accessors.
-- Second_Duration precision depends on the target clock precision.
function Day_Of_Week (Date : Ada.Calendar.Time) return Day_Name;
-- Return the day name
function Day_In_Year (Date : Ada.Calendar.Time) return Day_In_Year_Number;
-- Return the day number in the year. (1st January is day 1 and 31st
-- December is day 365 or 366 for leap year).
procedure Split
(Date : Ada.Calendar.Time;
Year : out Ada.Calendar.Year_Number;
Month : out Ada.Calendar.Month_Number;
Day : out Ada.Calendar.Day_Number;
Hour : out Hour_Number;
Minute : out Minute_Number;
Second : out Second_Number;
Sub_Second : out Second_Duration);
-- Split a standard Ada.Calendar.Time value in date data (Year, Month, Day)
-- and Time data (Hour, Minute, Second, Sub_Second).
procedure Split_At_Locale
(Date : Ada.Calendar.Time;
Year : out Ada.Calendar.Year_Number;
Month : out Ada.Calendar.Month_Number;
Day : out Ada.Calendar.Day_Number;
Hour : out Hour_Number;
Minute : out Minute_Number;
Second : out Second_Number;
Sub_Second : out Second_Duration);
-- Split a standard Ada.Calendar.Time value in date data (Year, Month, Day)
-- and Time data (Hour, Minute, Second, Sub_Second). This version of Split
-- utilizes the time zone and DST bias of the locale (equivalent to Clock).
-- Due to this simplified behavior, the implementation does not require
-- expensive system calls on targets such as Windows.
-- WARNING: Split_At_Locale is no longer aware of historic events and may
-- produce inaccurate results over DST changes which occurred in the past.
function Time_Of
(Year : Ada.Calendar.Year_Number;
Month : Ada.Calendar.Month_Number;
Day : Ada.Calendar.Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration := 0.0) return Ada.Calendar.Time;
-- Return an Ada.Calendar.Time data built from the date and time values
function Time_Of_At_Locale
(Year : Ada.Calendar.Year_Number;
Month : Ada.Calendar.Month_Number;
Day : Ada.Calendar.Day_Number;
Hour : Hour_Number;
Minute : Minute_Number;
Second : Second_Number;
Sub_Second : Second_Duration := 0.0) return Ada.Calendar.Time;
-- Return an Ada.Calendar.Time data built from the date and time values.
-- This version of Time_Of utilizes the time zone and DST bias of the
-- locale (equivalent to Clock). Due to this simplified behavior, the
-- implementation does not require expensive system calls on targets such
-- as Windows.
-- WARNING: Split_At_Locale is no longer aware of historic events and may
-- produce inaccurate results over DST changes which occurred in the past.
function Week_In_Year (Date : Ada.Calendar.Time) return Week_In_Year_Number;
-- Return the week number as defined in ISO 8601. A week always starts on
-- a Monday and the first week of a particular year is the one containing
-- the first Thursday. A year may have 53 weeks when January 1st is a
-- Wednesday and the year is leap or January 1st is a Thursday. Note that
-- the last days of December may belong to the first week on the next year
-- and conversely, the first days of January may belong to the last week
-- of the last year.
procedure Year_Week_In_Year
(Date : Ada.Calendar.Time;
Year : out Ada.Calendar.Year_Number;
Week : out Week_In_Year_Number);
-- Return the week number as defined in ISO 8601 along with the year in
-- which the week occurs.
-- C timeval conversion
-- C timeval represent a duration (used in Select for example). This
-- structure is composed of a number of seconds and a number of micro
-- seconds. The timeval structure is not exposed here because its
-- definition is target dependent. Interface to C programs is done via a
-- pointer to timeval structure.
type timeval is private;
function To_Duration (T : not null access timeval) return Duration;
function To_Timeval (D : Duration) return timeval;
private
-- This is a dummy declaration that should be the largest possible timeval
-- structure of all supported targets.
type timeval is array (1 .. 3) of Interfaces.C.long;
function Julian_Day
(Year : Ada.Calendar.Year_Number;
Month : Ada.Calendar.Month_Number;
Day : Ada.Calendar.Day_Number) return Integer;
-- Compute Julian day number
--
-- The code of this function is a modified version of algorithm 199 from
-- the Collected Algorithms of the ACM. The author of algorithm 199 is
-- Robert G. Tantzen.
No_Time : constant Ada.Calendar.Time :=
Ada.Calendar.Formatting.Time_Of
(Ada.Calendar.Year_Number'First,
Ada.Calendar.Month_Number'First,
Ada.Calendar.Day_Number'First,
Time_Zone => 0);
-- Use Time_Zone => 0 to be the same binary representation in any timezone
end GNAT.Calendar;
