summaryrefslogtreecommitdiff
path: root/gcc/ada/a-calfor.adb
blob: 39c3c0a2f799bb864bba38c23dba8b75d3ecd903 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--              A D A . C A L E N D A R . F O R M A T T I N G               --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2006-2010, 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.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Ada.Calendar;            use Ada.Calendar;
with Ada.Calendar.Time_Zones; use Ada.Calendar.Time_Zones;

package body Ada.Calendar.Formatting is

   --------------------------
   -- Implementation Notes --
   --------------------------

   --  All operations in this package are target and time representation
   --  independent, thus only one source file is needed for multiple targets.

   procedure Check_Char (S : String; C : Character; Index : Integer);
   --  Subsidiary to the two versions of Value. Determine whether the input
   --  string S has character C at position Index. Raise Constraint_Error if
   --  there is a mismatch.

   procedure Check_Digit (S : String; Index : Integer);
   --  Subsidiary to the two versions of Value. Determine whether the character
   --  of string S at position Index is a digit. This catches invalid input
   --  such as 1983-*1-j3 u5:n7:k9 which should be 1983-01-03 05:07:09. Raise
   --  Constraint_Error if there is a mismatch.

   ----------------
   -- Check_Char --
   ----------------

   procedure Check_Char (S : String; C : Character; Index : Integer) is
   begin
      if S (Index) /= C then
         raise Constraint_Error;
      end if;
   end Check_Char;

   -----------------
   -- Check_Digit --
   -----------------

   procedure Check_Digit (S : String; Index : Integer) is
   begin
      if S (Index) not in '0' .. '9' then
         raise Constraint_Error;
      end if;
   end Check_Digit;

   ---------
   -- Day --
   ---------

   function Day
     (Date      : Time;
      Time_Zone : Time_Zones.Time_Offset := 0) return Day_Number
   is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, Mo, H, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le, Time_Zone);
      return D;
   end Day;

   -----------------
   -- Day_Of_Week --
   -----------------

   function Day_Of_Week (Date : Time) return Day_Name is
   begin
      return Day_Name'Val (Formatting_Operations.Day_Of_Week (Date));
   end Day_Of_Week;

   ----------
   -- Hour --
   ----------

   function Hour
     (Date      : Time;
      Time_Zone : Time_Zones.Time_Offset := 0) return Hour_Number
   is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, Mo, D, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le, Time_Zone);
      return H;
   end Hour;

   -----------
   -- Image --
   -----------

   function Image
     (Elapsed_Time          : Duration;
      Include_Time_Fraction : Boolean := False) return String
   is
      Hour       : Hour_Number;
      Minute     : Minute_Number;
      Second     : Second_Number;
      Sub_Second : Duration;
      SS_Nat     : Natural;

      Low  : Integer;
      High : Integer;

      Result : String := "-00:00:00.00";

   begin
      Split (abs (Elapsed_Time), Hour, Minute, Second, Sub_Second);

      --  Determine the two slice bounds for the result string depending on
      --  whether the input is negative and whether fractions are requested.

      Low  := (if Elapsed_Time < 0.0 then 1 else 2);
      High := (if Include_Time_Fraction then 12 else 9);

      --  Prevent rounding when converting to natural

      Sub_Second := Sub_Second * 100.0;

      if Sub_Second > 0.0 then
         Sub_Second := Sub_Second - 0.5;
      end if;

      SS_Nat := Natural (Sub_Second);

      declare
         Hour_Str   : constant String := Hour_Number'Image (Hour);
         Minute_Str : constant String := Minute_Number'Image (Minute);
         Second_Str : constant String := Second_Number'Image (Second);
         SS_Str     : constant String := Natural'Image (SS_Nat);

      begin
         --  Hour processing, positions 2 and 3

         if Hour < 10 then
            Result (3) := Hour_Str (2);
         else
            Result (2) := Hour_Str (2);
            Result (3) := Hour_Str (3);
         end if;

         --  Minute processing, positions 5 and 6

         if Minute < 10 then
            Result (6) := Minute_Str (2);
         else
            Result (5) := Minute_Str (2);
            Result (6) := Minute_Str (3);
         end if;

         --  Second processing, positions 8 and 9

         if Second < 10 then
            Result (9) := Second_Str (2);
         else
            Result (8) := Second_Str (2);
            Result (9) := Second_Str (3);
         end if;

         --  Optional sub second processing, positions 11 and 12

         if Include_Time_Fraction then
            if SS_Nat < 10 then
               Result (12) := SS_Str (2);
            else
               Result (11) := SS_Str (2);
               Result (12) := SS_Str (3);
            end if;
         end if;

         return Result (Low .. High);
      end;
   end Image;

   -----------
   -- Image --
   -----------

   function Image
     (Date                  : Time;
      Include_Time_Fraction : Boolean := False;
      Time_Zone             : Time_Zones.Time_Offset := 0) return String
   is
      Year        : Year_Number;
      Month       : Month_Number;
      Day         : Day_Number;
      Hour        : Hour_Number;
      Minute      : Minute_Number;
      Second      : Second_Number;
      Sub_Second  : Duration;
      SS_Nat      : Natural;
      Leap_Second : Boolean;

      Result : String := "0000-00-00 00:00:00.00";

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

      --  Prevent rounding when converting to natural

      Sub_Second := Sub_Second * 100.0;

      if Sub_Second > 0.0 then
         Sub_Second := Sub_Second - 0.5;
      end if;

      SS_Nat := Natural (Sub_Second);

      declare
         Year_Str   : constant String := Year_Number'Image (Year);
         Month_Str  : constant String := Month_Number'Image (Month);
         Day_Str    : constant String := Day_Number'Image (Day);
         Hour_Str   : constant String := Hour_Number'Image (Hour);
         Minute_Str : constant String := Minute_Number'Image (Minute);
         Second_Str : constant String := Second_Number'Image (Second);
         SS_Str     : constant String := Natural'Image (SS_Nat);

      begin
         --  Year processing, positions 1, 2, 3 and 4

         Result (1) := Year_Str (2);
         Result (2) := Year_Str (3);
         Result (3) := Year_Str (4);
         Result (4) := Year_Str (5);

         --  Month processing, positions 6 and 7

         if Month < 10 then
            Result (7) := Month_Str (2);
         else
            Result (6) := Month_Str (2);
            Result (7) := Month_Str (3);
         end if;

         --  Day processing, positions 9 and 10

         if Day < 10 then
            Result (10) := Day_Str (2);
         else
            Result (9)  := Day_Str (2);
            Result (10) := Day_Str (3);
         end if;

         --  Hour processing, positions 12 and 13

         if Hour < 10 then
            Result (13) := Hour_Str (2);
         else
            Result (12) := Hour_Str (2);
            Result (13) := Hour_Str (3);
         end if;

         --  Minute processing, positions 15 and 16

         if Minute < 10 then
            Result (16) := Minute_Str (2);
         else
            Result (15) := Minute_Str (2);
            Result (16) := Minute_Str (3);
         end if;

         --  Second processing, positions 18 and 19

         if Second < 10 then
            Result (19) := Second_Str (2);
         else
            Result (18) := Second_Str (2);
            Result (19) := Second_Str (3);
         end if;

         --  Optional sub second processing, positions 21 and 22

         if Include_Time_Fraction then
            if SS_Nat < 10 then
               Result (22) := SS_Str (2);
            else
               Result (21) := SS_Str (2);
               Result (22) := SS_Str (3);
            end if;

            return Result;
         else
            return Result (1 .. 19);
         end if;
      end;
   end Image;

   ------------
   -- Minute --
   ------------

   function Minute
     (Date      : Time;
      Time_Zone : Time_Zones.Time_Offset := 0) return Minute_Number
   is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, Mo, D, H);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le, Time_Zone);
      return Mi;
   end Minute;

   -----------
   -- Month --
   -----------

   function Month
     (Date      : Time;
      Time_Zone : Time_Zones.Time_Offset := 0) return Month_Number
   is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, D, H, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le, Time_Zone);
      return Mo;
   end Month;

   ------------
   -- Second --
   ------------

   function Second (Date : Time) return Second_Number is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, Mo, D, H, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le);
      return Se;
   end Second;

   ----------------
   -- Seconds_Of --
   ----------------

   function Seconds_Of
     (Hour       : Hour_Number;
      Minute     : Minute_Number;
      Second     : Second_Number := 0;
      Sub_Second : Second_Duration := 0.0) return Day_Duration is

   begin
      --  Validity checks

      if not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Constraint_Error;
      end if;

      return Day_Duration (Hour   * 3_600) +
             Day_Duration (Minute *    60) +
             Day_Duration (Second)         +
             Sub_Second;
   end Seconds_Of;

   -----------
   -- Split --
   -----------

   procedure Split
     (Seconds    : Day_Duration;
      Hour       : out Hour_Number;
      Minute     : out Minute_Number;
      Second     : out Second_Number;
      Sub_Second : out Second_Duration)
   is
      Secs : Natural;

   begin
      --  Validity checks

      if not Seconds'Valid then
         raise Constraint_Error;
      end if;

      Secs := (if Seconds = 0.0 then 0 else Natural (Seconds - 0.5));

      Sub_Second := Second_Duration (Seconds - Day_Duration (Secs));
      Hour       := Hour_Number (Secs / 3_600);
      Secs       := Secs mod 3_600;
      Minute     := Minute_Number (Secs / 60);
      Second     := Second_Number (Secs mod 60);

      --  Validity checks

      if not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Time_Error;
      end if;
   end Split;

   -----------
   -- Split --
   -----------

   procedure Split
     (Date        : Time;
      Year        : out Year_Number;
      Month       : out Month_Number;
      Day         : out Day_Number;
      Seconds     : out Day_Duration;
      Leap_Second : out Boolean;
      Time_Zone   : Time_Zones.Time_Offset := 0)
   is
      H  : Integer;
      M  : Integer;
      Se : Integer;
      Su : Duration;
      Tz : constant Long_Integer := Long_Integer (Time_Zone);

   begin
      Formatting_Operations.Split
        (Date      => Date,
         Year      => Year,
         Month     => Month,
         Day       => Day,
         Day_Secs  => Seconds,
         Hour      => H,
         Minute    => M,
         Second    => Se,
         Sub_Sec   => Su,
         Leap_Sec  => Leap_Second,
         Time_Zone => Tz,
         Is_Ada_05 => True);

      --  Validity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Seconds'Valid
      then
         raise Time_Error;
      end if;
   end Split;

   -----------
   -- 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;
      Time_Zone  : Time_Zones.Time_Offset := 0)
   is
      Dd : Day_Duration;
      Le : Boolean;
      Tz : constant Long_Integer := Long_Integer (Time_Zone);

   begin
      Formatting_Operations.Split
        (Date      => Date,
         Year      => Year,
         Month     => Month,
         Day       => Day,
         Day_Secs  => Dd,
         Hour      => Hour,
         Minute    => Minute,
         Second    => Second,
         Sub_Sec   => Sub_Second,
         Leap_Sec  => Le,
         Time_Zone => Tz,
         Is_Ada_05 => True);

      --  Validity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Time_Error;
      end if;
   end Split;

   -----------
   -- 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;
      Leap_Second : out Boolean;
      Time_Zone   : Time_Zones.Time_Offset := 0)
   is
      Dd : Day_Duration;
      Tz : constant Long_Integer := Long_Integer (Time_Zone);

   begin
      Formatting_Operations.Split
       (Date      => Date,
        Year      => Year,
        Month     => Month,
        Day       => Day,
        Day_Secs  => Dd,
        Hour      => Hour,
        Minute    => Minute,
        Second    => Second,
        Sub_Sec   => Sub_Second,
        Leap_Sec  => Leap_Second,
        Time_Zone => Tz,
        Is_Ada_05 => True);

      --  Validity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Time_Error;
      end if;
   end Split;

   ----------------
   -- Sub_Second --
   ----------------

   function Sub_Second (Date : Time) return Second_Duration is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Y, Mo, D, H, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le);
      return Ss;
   end Sub_Second;

   -------------
   -- Time_Of --
   -------------

   function Time_Of
     (Year        : Year_Number;
      Month       : Month_Number;
      Day         : Day_Number;
      Seconds     : Day_Duration := 0.0;
      Leap_Second : Boolean := False;
      Time_Zone   : Time_Zones.Time_Offset := 0) return Time
   is
      Adj_Year  : Year_Number  := Year;
      Adj_Month : Month_Number := Month;
      Adj_Day   : Day_Number   := Day;

      H  : constant Integer := 1;
      M  : constant Integer := 1;
      Se : constant Integer := 1;
      Ss : constant Duration := 0.1;
      Tz : constant Long_Integer := Long_Integer (Time_Zone);

   begin
      --  Validity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Seconds'Valid
        or else not Time_Zone'Valid
      then
         raise Constraint_Error;
      end if;

      --  A Seconds value of 86_400 denotes a new day. This case requires an
      --  adjustment to the input values.

      if Seconds = 86_400.0 then
         if Day < Days_In_Month (Month)
           or else (Is_Leap (Year)
                      and then Month = 2)
         then
            Adj_Day := Day + 1;
         else
            Adj_Day := 1;

            if Month < 12 then
               Adj_Month := Month + 1;
            else
               Adj_Month := 1;
               Adj_Year  := Year + 1;
            end if;
         end if;
      end if;

      return
        Formatting_Operations.Time_Of
          (Year         => Adj_Year,
           Month        => Adj_Month,
           Day          => Adj_Day,
           Day_Secs     => Seconds,
           Hour         => H,
           Minute       => M,
           Second       => Se,
           Sub_Sec      => Ss,
           Leap_Sec     => Leap_Second,
           Use_Day_Secs => True,
           Is_Ada_05    => True,
           Time_Zone    => Tz);
   end Time_Of;

   -------------
   -- 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;
      Leap_Second : Boolean := False;
      Time_Zone   : Time_Zones.Time_Offset := 0) return Time
   is
      Dd : constant Day_Duration := Day_Duration'First;
      Tz : constant Long_Integer := Long_Integer (Time_Zone);

   begin
      --  Validity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
        or else not Time_Zone'Valid
      then
         raise Constraint_Error;
      end if;

      return
        Formatting_Operations.Time_Of
          (Year         => Year,
           Month        => Month,
           Day          => Day,
           Day_Secs     => Dd,
           Hour         => Hour,
           Minute       => Minute,
           Second       => Second,
           Sub_Sec      => Sub_Second,
           Leap_Sec     => Leap_Second,
           Use_Day_Secs => False,
           Is_Ada_05    => True,
           Time_Zone    => Tz);
   end Time_Of;

   -----------
   -- Value --
   -----------

   function Value
     (Date      : String;
      Time_Zone : Time_Zones.Time_Offset := 0) return Time
   is
      D          : String (1 .. 22);
      Year       : Year_Number;
      Month      : Month_Number;
      Day        : Day_Number;
      Hour       : Hour_Number;
      Minute     : Minute_Number;
      Second     : Second_Number;
      Sub_Second : Second_Duration := 0.0;

   begin
      --  Validity checks

      if not Time_Zone'Valid then
         raise Constraint_Error;
      end if;

      --  Length checks

      if Date'Length /= 19
        and then Date'Length /= 22
      then
         raise Constraint_Error;
      end if;

      --  After the correct length has been determined, it is safe to copy the
      --  Date in order to avoid Date'First + N indexing.

      D (1 .. Date'Length) := Date;

      --  Format checks

      Check_Char (D, '-', 5);
      Check_Char (D, '-', 8);
      Check_Char (D, ' ', 11);
      Check_Char (D, ':', 14);
      Check_Char (D, ':', 17);

      if Date'Length = 22 then
         Check_Char (D, '.', 20);
      end if;

      --  Leading zero checks

      Check_Digit (D, 6);
      Check_Digit (D, 9);
      Check_Digit (D, 12);
      Check_Digit (D, 15);
      Check_Digit (D, 18);

      if Date'Length = 22 then
         Check_Digit (D, 21);
      end if;

      --  Value extraction

      Year   := Year_Number   (Year_Number'Value   (D (1 .. 4)));
      Month  := Month_Number  (Month_Number'Value  (D (6 .. 7)));
      Day    := Day_Number    (Day_Number'Value    (D (9 .. 10)));
      Hour   := Hour_Number   (Hour_Number'Value   (D (12 .. 13)));
      Minute := Minute_Number (Minute_Number'Value (D (15 .. 16)));
      Second := Second_Number (Second_Number'Value (D (18 .. 19)));

      --  Optional part

      if Date'Length = 22 then
         Sub_Second := Second_Duration (Second_Duration'Value (D (20 .. 22)));
      end if;

      --  Sanity checks

      if not Year'Valid
        or else not Month'Valid
        or else not Day'Valid
        or else not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Constraint_Error;
      end if;

      return Time_Of (Year, Month, Day,
                      Hour, Minute, Second, Sub_Second, False, Time_Zone);

   exception
      when others => raise Constraint_Error;
   end Value;

   -----------
   -- Value --
   -----------

   function Value (Elapsed_Time : String) return Duration is
      D          : String (1 .. 11);
      Hour       : Hour_Number;
      Minute     : Minute_Number;
      Second     : Second_Number;
      Sub_Second : Second_Duration := 0.0;

   begin
      --  Length checks

      if Elapsed_Time'Length /= 8
        and then Elapsed_Time'Length /= 11
      then
         raise Constraint_Error;
      end if;

      --  After the correct length has been determined, it is safe to copy the
      --  Elapsed_Time in order to avoid Date'First + N indexing.

      D (1 .. Elapsed_Time'Length) := Elapsed_Time;

      --  Format checks

      Check_Char (D, ':', 3);
      Check_Char (D, ':', 6);

      if Elapsed_Time'Length = 11 then
         Check_Char (D, '.', 9);
      end if;

      --  Leading zero checks

      Check_Digit (D, 1);
      Check_Digit (D, 4);
      Check_Digit (D, 7);

      if Elapsed_Time'Length = 11 then
         Check_Digit (D, 10);
      end if;

      --  Value extraction

      Hour   := Hour_Number   (Hour_Number'Value   (D (1 .. 2)));
      Minute := Minute_Number (Minute_Number'Value (D (4 .. 5)));
      Second := Second_Number (Second_Number'Value (D (7 .. 8)));

      --  Optional part

      if Elapsed_Time'Length = 11 then
         Sub_Second := Second_Duration (Second_Duration'Value (D (9 .. 11)));
      end if;

      --  Sanity checks

      if not Hour'Valid
        or else not Minute'Valid
        or else not Second'Valid
        or else not Sub_Second'Valid
      then
         raise Constraint_Error;
      end if;

      return Seconds_Of (Hour, Minute, Second, Sub_Second);

   exception
      when others => raise Constraint_Error;
   end Value;

   ----------
   -- Year --
   ----------

   function Year
     (Date      : Time;
      Time_Zone : Time_Zones.Time_Offset := 0) return Year_Number
   is
      Y  : Year_Number;
      Mo : Month_Number;
      D  : Day_Number;
      H  : Hour_Number;
      Mi : Minute_Number;
      Se : Second_Number;
      Ss : Second_Duration;
      Le : Boolean;

      pragma Unreferenced (Mo, D, H, Mi);

   begin
      Split (Date, Y, Mo, D, H, Mi, Se, Ss, Le, Time_Zone);
      return Y;
   end Year;

end Ada.Calendar.Formatting;