File : 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) 1999-2016, 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- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This package extends Ada.Calendar to handle Hour, Minute, Second,
33 -- Second_Duration and Day_Of_Week and Day_In_Year from Calendar.Time.
34 -- Second_Duration precision depends on the target clock precision.
35 --
36 -- GNAT.Calendar provides the same kind of abstraction found in Ada.Calendar.
37 -- It provides Split and Time_Of to build and split a Time data. And it
38 -- provides accessor functions to get only one of Hour, Minute, Second,
39 -- Second_Duration. Other functions are to access more advanced values like
40 -- Day_Of_Week, Day_In_Year and Week_In_Year.
41
42 with Ada.Calendar.Formatting;
43 with Interfaces.C;
44
45 package GNAT.Calendar is
46
47 type Day_Name is
48 (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday);
49 pragma Ordered (Day_Name);
50
51 subtype Hour_Number is Natural range 0 .. 23;
52 subtype Minute_Number is Natural range 0 .. 59;
53 subtype Second_Number is Natural range 0 .. 59;
54 subtype Second_Duration is Ada.Calendar.Day_Duration range 0.0 .. 1.0;
55 subtype Day_In_Year_Number is Positive range 1 .. 366;
56 subtype Week_In_Year_Number is Positive range 1 .. 53;
57
58 No_Time : constant Ada.Calendar.Time;
59 -- A constant set to the first date that can be represented by the type
60 -- Time. It can be used to indicate an uninitialized date.
61
62 function Hour (Date : Ada.Calendar.Time) return Hour_Number;
63 function Minute (Date : Ada.Calendar.Time) return Minute_Number;
64 function Second (Date : Ada.Calendar.Time) return Second_Number;
65 function Sub_Second (Date : Ada.Calendar.Time) return Second_Duration;
66 -- Hour, Minute, Second and Sub_Second returns the complete time data for
67 -- the Date (H:M:S.SS). See Ada.Calendar for Year, Month, Day accessors.
68 -- Second_Duration precision depends on the target clock precision.
69
70 function Day_Of_Week (Date : Ada.Calendar.Time) return Day_Name;
71 -- Return the day name
72
73 function Day_In_Year (Date : Ada.Calendar.Time) return Day_In_Year_Number;
74 -- Return the day number in the year. (1st January is day 1 and 31st
75 -- December is day 365 or 366 for leap year).
76
77 procedure Split
78 (Date : Ada.Calendar.Time;
79 Year : out Ada.Calendar.Year_Number;
80 Month : out Ada.Calendar.Month_Number;
81 Day : out Ada.Calendar.Day_Number;
82 Hour : out Hour_Number;
83 Minute : out Minute_Number;
84 Second : out Second_Number;
85 Sub_Second : out Second_Duration);
86 -- Split a standard Ada.Calendar.Time value in date data (Year, Month, Day)
87 -- and Time data (Hour, Minute, Second, Sub_Second).
88
89 procedure Split_At_Locale
90 (Date : Ada.Calendar.Time;
91 Year : out Ada.Calendar.Year_Number;
92 Month : out Ada.Calendar.Month_Number;
93 Day : out Ada.Calendar.Day_Number;
94 Hour : out Hour_Number;
95 Minute : out Minute_Number;
96 Second : out Second_Number;
97 Sub_Second : out Second_Duration);
98 -- Split a standard Ada.Calendar.Time value in date data (Year, Month, Day)
99 -- and Time data (Hour, Minute, Second, Sub_Second). This version of Split
100 -- utilizes the time zone and DST bias of the locale (equivalent to Clock).
101 -- Due to this simplified behavior, the implementation does not require
102 -- expensive system calls on targets such as Windows.
103 -- WARNING: Split_At_Locale is no longer aware of historic events and may
104 -- produce inaccurate results over DST changes which occurred in the past.
105
106 function Time_Of
107 (Year : Ada.Calendar.Year_Number;
108 Month : Ada.Calendar.Month_Number;
109 Day : Ada.Calendar.Day_Number;
110 Hour : Hour_Number;
111 Minute : Minute_Number;
112 Second : Second_Number;
113 Sub_Second : Second_Duration := 0.0) return Ada.Calendar.Time;
114 -- Return an Ada.Calendar.Time data built from the date and time values
115
116 function Time_Of_At_Locale
117 (Year : Ada.Calendar.Year_Number;
118 Month : Ada.Calendar.Month_Number;
119 Day : Ada.Calendar.Day_Number;
120 Hour : Hour_Number;
121 Minute : Minute_Number;
122 Second : Second_Number;
123 Sub_Second : Second_Duration := 0.0) return Ada.Calendar.Time;
124 -- Return an Ada.Calendar.Time data built from the date and time values.
125 -- This version of Time_Of utilizes the time zone and DST bias of the
126 -- locale (equivalent to Clock). Due to this simplified behavior, the
127 -- implementation does not require expensive system calls on targets such
128 -- as Windows.
129 -- WARNING: Split_At_Locale is no longer aware of historic events and may
130 -- produce inaccurate results over DST changes which occurred in the past.
131
132 function Week_In_Year (Date : Ada.Calendar.Time) return Week_In_Year_Number;
133 -- Return the week number as defined in ISO 8601. A week always starts on
134 -- a Monday and the first week of a particular year is the one containing
135 -- the first Thursday. A year may have 53 weeks when January 1st is a
136 -- Wednesday and the year is leap or January 1st is a Thursday. Note that
137 -- the last days of December may belong to the first week on the next year
138 -- and conversely, the first days of January may belong to the last week
139 -- of the last year.
140
141 procedure Year_Week_In_Year
142 (Date : Ada.Calendar.Time;
143 Year : out Ada.Calendar.Year_Number;
144 Week : out Week_In_Year_Number);
145 -- Return the week number as defined in ISO 8601 along with the year in
146 -- which the week occurs.
147
148 -- C timeval conversion
149
150 -- C timeval represent a duration (used in Select for example). This
151 -- structure is composed of a number of seconds and a number of micro
152 -- seconds. The timeval structure is not exposed here because its
153 -- definition is target dependent. Interface to C programs is done via a
154 -- pointer to timeval structure.
155
156 type timeval is private;
157
158 function To_Duration (T : not null access timeval) return Duration;
159 function To_Timeval (D : Duration) return timeval;
160
161 private
162 -- This is a dummy declaration that should be the largest possible timeval
163 -- structure of all supported targets.
164
165 type timeval is array (1 .. 3) of Interfaces.C.long;
166
167 function Julian_Day
168 (Year : Ada.Calendar.Year_Number;
169 Month : Ada.Calendar.Month_Number;
170 Day : Ada.Calendar.Day_Number) return Integer;
171 -- Compute Julian day number
172 --
173 -- The code of this function is a modified version of algorithm 199 from
174 -- the Collected Algorithms of the ACM. The author of algorithm 199 is
175 -- Robert G. Tantzen.
176
177 No_Time : constant Ada.Calendar.Time :=
178 Ada.Calendar.Formatting.Time_Of
179 (Ada.Calendar.Year_Number'First,
180 Ada.Calendar.Month_Number'First,
181 Ada.Calendar.Day_Number'First,
182 Time_Zone => 0);
183 -- Use Time_Zone => 0 to be the same binary representation in any timezone
184
185 end GNAT.Calendar;