File : g-calend.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- G N A T . C A L E N D A R --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1999-2014, AdaCore --
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 with Interfaces.C.Extensions;
33
34 package body GNAT.Calendar is
35 use Ada.Calendar;
36 use Interfaces;
37
38 -----------------
39 -- Day_In_Year --
40 -----------------
41
42 function Day_In_Year (Date : Time) return Day_In_Year_Number is
43 Year : Year_Number;
44 Month : Month_Number;
45 Day : Day_Number;
46 Day_Secs : Day_Duration;
47 pragma Unreferenced (Day_Secs);
48 begin
49 Split (Date, Year, Month, Day, Day_Secs);
50 return Julian_Day (Year, Month, Day) - Julian_Day (Year, 1, 1) + 1;
51 end Day_In_Year;
52
53 -----------------
54 -- Day_Of_Week --
55 -----------------
56
57 function Day_Of_Week (Date : Time) return Day_Name is
58 Year : Year_Number;
59 Month : Month_Number;
60 Day : Day_Number;
61 Day_Secs : Day_Duration;
62 pragma Unreferenced (Day_Secs);
63 begin
64 Split (Date, Year, Month, Day, Day_Secs);
65 return Day_Name'Val ((Julian_Day (Year, Month, Day)) mod 7);
66 end Day_Of_Week;
67
68 ----------
69 -- Hour --
70 ----------
71
72 function Hour (Date : Time) return Hour_Number is
73 Year : Year_Number;
74 Month : Month_Number;
75 Day : Day_Number;
76 Hour : Hour_Number;
77 Minute : Minute_Number;
78 Second : Second_Number;
79 Sub_Second : Second_Duration;
80 pragma Unreferenced (Year, Month, Day, Minute, Second, Sub_Second);
81 begin
82 Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
83 return Hour;
84 end Hour;
85
86 ----------------
87 -- Julian_Day --
88 ----------------
89
90 -- Julian_Day is used to by Day_Of_Week and Day_In_Year. Note that this
91 -- implementation is not expensive.
92
93 function Julian_Day
94 (Year : Year_Number;
95 Month : Month_Number;
96 Day : Day_Number) return Integer
97 is
98 Internal_Year : Integer;
99 Internal_Month : Integer;
100 Internal_Day : Integer;
101 Julian_Date : Integer;
102 C : Integer;
103 Ya : Integer;
104
105 begin
106 Internal_Year := Integer (Year);
107 Internal_Month := Integer (Month);
108 Internal_Day := Integer (Day);
109
110 if Internal_Month > 2 then
111 Internal_Month := Internal_Month - 3;
112 else
113 Internal_Month := Internal_Month + 9;
114 Internal_Year := Internal_Year - 1;
115 end if;
116
117 C := Internal_Year / 100;
118 Ya := Internal_Year - (100 * C);
119
120 Julian_Date := (146_097 * C) / 4 +
121 (1_461 * Ya) / 4 +
122 (153 * Internal_Month + 2) / 5 +
123 Internal_Day + 1_721_119;
124
125 return Julian_Date;
126 end Julian_Day;
127
128 ------------
129 -- Minute --
130 ------------
131
132 function Minute (Date : Time) return Minute_Number is
133 Year : Year_Number;
134 Month : Month_Number;
135 Day : Day_Number;
136 Hour : Hour_Number;
137 Minute : Minute_Number;
138 Second : Second_Number;
139 Sub_Second : Second_Duration;
140 pragma Unreferenced (Year, Month, Day, Hour, Second, Sub_Second);
141 begin
142 Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
143 return Minute;
144 end Minute;
145
146 ------------
147 -- Second --
148 ------------
149
150 function Second (Date : Time) return Second_Number is
151 Year : Year_Number;
152 Month : Month_Number;
153 Day : Day_Number;
154 Hour : Hour_Number;
155 Minute : Minute_Number;
156 Second : Second_Number;
157 Sub_Second : Second_Duration;
158 pragma Unreferenced (Year, Month, Day, Hour, Minute, Sub_Second);
159 begin
160 Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
161 return Second;
162 end Second;
163
164 -----------
165 -- Split --
166 -----------
167
168 procedure Split
169 (Date : Time;
170 Year : out Year_Number;
171 Month : out Month_Number;
172 Day : out Day_Number;
173 Hour : out Hour_Number;
174 Minute : out Minute_Number;
175 Second : out Second_Number;
176 Sub_Second : out Second_Duration)
177 is
178 Day_Secs : Day_Duration;
179 Secs : Natural;
180
181 begin
182 Split (Date, Year, Month, Day, Day_Secs);
183
184 Secs := (if Day_Secs = 0.0 then 0 else Natural (Day_Secs - 0.5));
185 Sub_Second := Second_Duration (Day_Secs - Day_Duration (Secs));
186 Hour := Hour_Number (Secs / 3_600);
187 Secs := Secs mod 3_600;
188 Minute := Minute_Number (Secs / 60);
189 Second := Second_Number (Secs mod 60);
190 end Split;
191
192 ---------------------
193 -- Split_At_Locale --
194 ---------------------
195
196 procedure Split_At_Locale
197 (Date : Time;
198 Year : out Year_Number;
199 Month : out Month_Number;
200 Day : out Day_Number;
201 Hour : out Hour_Number;
202 Minute : out Minute_Number;
203 Second : out Second_Number;
204 Sub_Second : out Second_Duration)
205 is
206 procedure Ada_Calendar_Split
207 (Date : Time;
208 Year : out Year_Number;
209 Month : out Month_Number;
210 Day : out Day_Number;
211 Day_Secs : out Day_Duration;
212 Hour : out Integer;
213 Minute : out Integer;
214 Second : out Integer;
215 Sub_Sec : out Duration;
216 Leap_Sec : out Boolean;
217 Use_TZ : Boolean;
218 Is_Historic : Boolean;
219 Time_Zone : Long_Integer);
220 pragma Import (Ada, Ada_Calendar_Split, "__gnat_split");
221
222 Ds : Day_Duration;
223 Le : Boolean;
224
225 pragma Unreferenced (Ds, Le);
226
227 begin
228 -- Even though the input time zone is UTC (0), the flag Use_TZ will
229 -- ensure that Split picks up the local time zone.
230
231 Ada_Calendar_Split
232 (Date => Date,
233 Year => Year,
234 Month => Month,
235 Day => Day,
236 Day_Secs => Ds,
237 Hour => Hour,
238 Minute => Minute,
239 Second => Second,
240 Sub_Sec => Sub_Second,
241 Leap_Sec => Le,
242 Use_TZ => False,
243 Is_Historic => False,
244 Time_Zone => 0);
245 end Split_At_Locale;
246
247 ----------------
248 -- Sub_Second --
249 ----------------
250
251 function Sub_Second (Date : Time) return Second_Duration is
252 Year : Year_Number;
253 Month : Month_Number;
254 Day : Day_Number;
255 Hour : Hour_Number;
256 Minute : Minute_Number;
257 Second : Second_Number;
258 Sub_Second : Second_Duration;
259 pragma Unreferenced (Year, Month, Day, Hour, Minute, Second);
260 begin
261 Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
262 return Sub_Second;
263 end Sub_Second;
264
265 -------------
266 -- Time_Of --
267 -------------
268
269 function Time_Of
270 (Year : Year_Number;
271 Month : Month_Number;
272 Day : Day_Number;
273 Hour : Hour_Number;
274 Minute : Minute_Number;
275 Second : Second_Number;
276 Sub_Second : Second_Duration := 0.0) return Time
277 is
278 Day_Secs : constant Day_Duration :=
279 Day_Duration (Hour * 3_600) +
280 Day_Duration (Minute * 60) +
281 Day_Duration (Second) +
282 Sub_Second;
283 begin
284 return Time_Of (Year, Month, Day, Day_Secs);
285 end Time_Of;
286
287 -----------------------
288 -- Time_Of_At_Locale --
289 -----------------------
290
291 function Time_Of_At_Locale
292 (Year : Year_Number;
293 Month : Month_Number;
294 Day : Day_Number;
295 Hour : Hour_Number;
296 Minute : Minute_Number;
297 Second : Second_Number;
298 Sub_Second : Second_Duration := 0.0) return Time
299 is
300 function Ada_Calendar_Time_Of
301 (Year : Year_Number;
302 Month : Month_Number;
303 Day : Day_Number;
304 Day_Secs : Day_Duration;
305 Hour : Integer;
306 Minute : Integer;
307 Second : Integer;
308 Sub_Sec : Duration;
309 Leap_Sec : Boolean;
310 Use_Day_Secs : Boolean;
311 Use_TZ : Boolean;
312 Is_Historic : Boolean;
313 Time_Zone : Long_Integer) return Time;
314 pragma Import (Ada, Ada_Calendar_Time_Of, "__gnat_time_of");
315
316 begin
317 -- Even though the input time zone is UTC (0), the flag Use_TZ will
318 -- ensure that Split picks up the local time zone.
319
320 return
321 Ada_Calendar_Time_Of
322 (Year => Year,
323 Month => Month,
324 Day => Day,
325 Day_Secs => 0.0,
326 Hour => Hour,
327 Minute => Minute,
328 Second => Second,
329 Sub_Sec => Sub_Second,
330 Leap_Sec => False,
331 Use_Day_Secs => False,
332 Use_TZ => False,
333 Is_Historic => False,
334 Time_Zone => 0);
335 end Time_Of_At_Locale;
336
337 -----------------
338 -- To_Duration --
339 -----------------
340
341 function To_Duration (T : not null access timeval) return Duration is
342
343 procedure timeval_to_duration
344 (T : not null access timeval;
345 sec : not null access C.Extensions.long_long;
346 usec : not null access C.long);
347 pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
348
349 Micro : constant := 10**6;
350 sec : aliased C.Extensions.long_long;
351 usec : aliased C.long;
352
353 begin
354 timeval_to_duration (T, sec'Access, usec'Access);
355 return Duration (sec) + Duration (usec) / Micro;
356 end To_Duration;
357
358 ----------------
359 -- To_Timeval --
360 ----------------
361
362 function To_Timeval (D : Duration) return timeval is
363
364 procedure duration_to_timeval
365 (Sec : C.Extensions.long_long;
366 Usec : C.long;
367 T : not null access timeval);
368 pragma Import (C, duration_to_timeval, "__gnat_duration_to_timeval");
369
370 Micro : constant := 10**6;
371 Result : aliased timeval;
372 sec : C.Extensions.long_long;
373 usec : C.long;
374
375 begin
376 if D = 0.0 then
377 sec := 0;
378 usec := 0;
379 else
380 sec := C.Extensions.long_long (D - 0.5);
381 usec := C.long ((D - Duration (sec)) * Micro - 0.5);
382 end if;
383
384 duration_to_timeval (sec, usec, Result'Access);
385
386 return Result;
387 end To_Timeval;
388
389 ------------------
390 -- Week_In_Year --
391 ------------------
392
393 function Week_In_Year (Date : Time) return Week_In_Year_Number is
394 Year : Year_Number;
395 Week : Week_In_Year_Number;
396 pragma Unreferenced (Year);
397 begin
398 Year_Week_In_Year (Date, Year, Week);
399 return Week;
400 end Week_In_Year;
401
402 -----------------------
403 -- Year_Week_In_Year --
404 -----------------------
405
406 procedure Year_Week_In_Year
407 (Date : Time;
408 Year : out Year_Number;
409 Week : out Week_In_Year_Number)
410 is
411 Month : Month_Number;
412 Day : Day_Number;
413 Hour : Hour_Number;
414 Minute : Minute_Number;
415 Second : Second_Number;
416 Sub_Second : Second_Duration;
417 Jan_1 : Day_Name;
418 Shift : Week_In_Year_Number;
419 Start_Week : Week_In_Year_Number;
420
421 pragma Unreferenced (Hour, Minute, Second, Sub_Second);
422
423 function Is_Leap (Year : Year_Number) return Boolean;
424 -- Return True if Year denotes a leap year. Leap centennial years are
425 -- properly handled.
426
427 function Jan_1_Day_Of_Week
428 (Jan_1 : Day_Name;
429 Year : Year_Number;
430 Last_Year : Boolean := False;
431 Next_Year : Boolean := False) return Day_Name;
432 -- Given the weekday of January 1 in Year, determine the weekday on
433 -- which January 1 fell last year or will fall next year as set by
434 -- the two flags. This routine does not call Time_Of or Split.
435
436 function Last_Year_Has_53_Weeks
437 (Jan_1 : Day_Name;
438 Year : Year_Number) return Boolean;
439 -- Given the weekday of January 1 in Year, determine whether last year
440 -- has 53 weeks. A False value implies that the year has 52 weeks.
441
442 -------------
443 -- Is_Leap --
444 -------------
445
446 function Is_Leap (Year : Year_Number) return Boolean is
447 begin
448 if Year mod 400 = 0 then
449 return True;
450 elsif Year mod 100 = 0 then
451 return False;
452 else
453 return Year mod 4 = 0;
454 end if;
455 end Is_Leap;
456
457 -----------------------
458 -- Jan_1_Day_Of_Week --
459 -----------------------
460
461 function Jan_1_Day_Of_Week
462 (Jan_1 : Day_Name;
463 Year : Year_Number;
464 Last_Year : Boolean := False;
465 Next_Year : Boolean := False) return Day_Name
466 is
467 Shift : Integer := 0;
468
469 begin
470 if Last_Year then
471 Shift := (if Is_Leap (Year - 1) then -2 else -1);
472 elsif Next_Year then
473 Shift := (if Is_Leap (Year) then 2 else 1);
474 end if;
475
476 return Day_Name'Val ((Day_Name'Pos (Jan_1) + Shift) mod 7);
477 end Jan_1_Day_Of_Week;
478
479 ----------------------------
480 -- Last_Year_Has_53_Weeks --
481 ----------------------------
482
483 function Last_Year_Has_53_Weeks
484 (Jan_1 : Day_Name;
485 Year : Year_Number) return Boolean
486 is
487 Last_Jan_1 : constant Day_Name :=
488 Jan_1_Day_Of_Week (Jan_1, Year, Last_Year => True);
489
490 begin
491 -- These two cases are illustrated in the table below
492
493 return
494 Last_Jan_1 = Thursday
495 or else (Last_Jan_1 = Wednesday and then Is_Leap (Year - 1));
496 end Last_Year_Has_53_Weeks;
497
498 -- Start of processing for Week_In_Year
499
500 begin
501 Split (Date, Year, Month, Day, Hour, Minute, Second, Sub_Second);
502
503 -- According to ISO 8601, the first week of year Y is the week that
504 -- contains the first Thursday in year Y. The following table contains
505 -- all possible combinations of years and weekdays along with examples.
506
507 -- +-------+------+-------+---------+
508 -- | Jan 1 | Leap | Weeks | Example |
509 -- +-------+------+-------+---------+
510 -- | Mon | No | 52 | 2007 |
511 -- +-------+------+-------+---------+
512 -- | Mon | Yes | 52 | 1996 |
513 -- +-------+------+-------+---------+
514 -- | Tue | No | 52 | 2002 |
515 -- +-------+------+-------+---------+
516 -- | Tue | Yes | 52 | 1980 |
517 -- +-------+------+-------+---------+
518 -- | Wed | No | 52 | 2003 |
519 -- +-------+------#########---------+
520 -- | Wed | Yes # 53 # 1992 |
521 -- +-------+------#-------#---------+
522 -- | Thu | No # 53 # 1998 |
523 -- +-------+------#-------#---------+
524 -- | Thu | Yes # 53 # 2004 |
525 -- +-------+------#########---------+
526 -- | Fri | No | 52 | 1999 |
527 -- +-------+------+-------+---------+
528 -- | Fri | Yes | 52 | 1988 |
529 -- +-------+------+-------+---------+
530 -- | Sat | No | 52 | 1994 |
531 -- +-------+------+-------+---------+
532 -- | Sat | Yes | 52 | 1972 |
533 -- +-------+------+-------+---------+
534 -- | Sun | No | 52 | 1995 |
535 -- +-------+------+-------+---------+
536 -- | Sun | Yes | 52 | 1956 |
537 -- +-------+------+-------+---------+
538
539 -- A small optimization, the input date is January 1. Note that this
540 -- is a key day since it determines the number of weeks and is used
541 -- when special casing the first week of January and the last week of
542 -- December.
543
544 Jan_1 := Day_Of_Week (if Day = 1 and then Month = 1
545 then Date
546 else (Time_Of (Year, 1, 1, 0.0)));
547
548 -- Special cases for January
549
550 if Month = 1 then
551
552 -- Special case 1: January 1, 2 and 3. These three days may belong
553 -- to last year's last week which can be week number 52 or 53.
554
555 -- +-----+-----+-----+=====+-----+-----+-----+
556 -- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
557 -- +-----+-----+-----+-----+-----+-----+-----+
558 -- | 26 | 27 | 28 # 29 # 30 | 31 | 1 |
559 -- +-----+-----+-----+-----+-----+-----+-----+
560 -- | 27 | 28 | 29 # 30 # 31 | 1 | 2 |
561 -- +-----+-----+-----+-----+-----+-----+-----+
562 -- | 28 | 29 | 30 # 31 # 1 | 2 | 3 |
563 -- +-----+-----+-----+=====+-----+-----+-----+
564
565 if (Day = 1 and then Jan_1 in Friday .. Sunday)
566 or else
567 (Day = 2 and then Jan_1 in Friday .. Saturday)
568 or else
569 (Day = 3 and then Jan_1 = Friday)
570 then
571 Week := (if Last_Year_Has_53_Weeks (Jan_1, Year) then 53 else 52);
572
573 -- January 1, 2 and 3 belong to the previous year
574
575 Year := Year - 1;
576 return;
577
578 -- Special case 2: January 1, 2, 3, 4, 5, 6 and 7 of the first week
579
580 -- +-----+-----+-----+=====+-----+-----+-----+
581 -- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
582 -- +-----+-----+-----+-----+-----+-----+-----+
583 -- | 29 | 30 | 31 # 1 # 2 | 3 | 4 |
584 -- +-----+-----+-----+-----+-----+-----+-----+
585 -- | 30 | 31 | 1 # 2 # 3 | 4 | 5 |
586 -- +-----+-----+-----+-----+-----+-----+-----+
587 -- | 31 | 1 | 2 # 3 # 4 | 5 | 6 |
588 -- +-----+-----+-----+-----+-----+-----+-----+
589 -- | 1 | 2 | 3 # 4 # 5 | 6 | 7 |
590 -- +-----+-----+-----+=====+-----+-----+-----+
591
592 elsif (Day <= 4 and then Jan_1 in Monday .. Thursday)
593 or else
594 (Day = 5 and then Jan_1 in Monday .. Wednesday)
595 or else
596 (Day = 6 and then Jan_1 in Monday .. Tuesday)
597 or else
598 (Day = 7 and then Jan_1 = Monday)
599 then
600 Week := 1;
601 return;
602 end if;
603
604 -- Month other than 1
605
606 -- Special case 3: December 29, 30 and 31. These days may belong to
607 -- next year's first week.
608
609 -- +-----+-----+-----+=====+-----+-----+-----+
610 -- | Mon | Tue | Wed # Thu # Fri | Sat | Sun |
611 -- +-----+-----+-----+-----+-----+-----+-----+
612 -- | 29 | 30 | 31 # 1 # 2 | 3 | 4 |
613 -- +-----+-----+-----+-----+-----+-----+-----+
614 -- | 30 | 31 | 1 # 2 # 3 | 4 | 5 |
615 -- +-----+-----+-----+-----+-----+-----+-----+
616 -- | 31 | 1 | 2 # 3 # 4 | 5 | 6 |
617 -- +-----+-----+-----+=====+-----+-----+-----+
618
619 elsif Month = 12 and then Day > 28 then
620 declare
621 Next_Jan_1 : constant Day_Name :=
622 Jan_1_Day_Of_Week (Jan_1, Year, Next_Year => True);
623 begin
624 if (Day = 29 and then Next_Jan_1 = Thursday)
625 or else
626 (Day = 30 and then Next_Jan_1 in Wednesday .. Thursday)
627 or else
628 (Day = 31 and then Next_Jan_1 in Tuesday .. Thursday)
629 then
630 Year := Year + 1;
631 Week := 1;
632 return;
633 end if;
634 end;
635 end if;
636
637 -- Determine the week from which to start counting. If January 1 does
638 -- not belong to the first week of the input year, then the next week
639 -- is the first week.
640
641 Start_Week := (if Jan_1 in Friday .. Sunday then 1 else 2);
642
643 -- At this point all special combinations have been accounted for and
644 -- the proper start week has been found. Since January 1 may not fall
645 -- on a Monday, shift 7 - Day_Name'Pos (Jan_1). This action ensures an
646 -- origin which falls on Monday.
647
648 Shift := 7 - Day_Name'Pos (Jan_1);
649 Week := Start_Week + (Day_In_Year (Date) - Shift - 1) / 7;
650 end Year_Week_In_Year;
651
652 end GNAT.Calendar;