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
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
// This is a part of Chrono.
// See README.md and LICENSE.txt for details.

//! A collection of parsed date and time items.
//! They can be constructed incrementally while being checked for consistency.

use num_integer::div_rem;
use num_traits::ToPrimitive;

use super::{ParseResult, IMPOSSIBLE, NOT_ENOUGH, OUT_OF_RANGE};
use crate::naive::{NaiveDate, NaiveDateTime, NaiveTime};
use crate::offset::{FixedOffset, LocalResult, Offset, TimeZone};
use crate::oldtime::Duration as OldDuration;
use crate::DateTime;
use crate::Weekday;
use crate::{Datelike, Timelike};

/// Parsed parts of date and time. There are two classes of methods:
///
/// - `set_*` methods try to set given field(s) while checking for the consistency.
///   It may or may not check for the range constraint immediately (for efficiency reasons).
///
/// - `to_*` methods try to make a concrete date and time value out of set fields.
///   It fully checks any remaining out-of-range conditions and inconsistent/impossible fields.
#[derive(Clone, PartialEq, Eq, Debug, Default)]
pub struct Parsed {
    /// Year.
    ///
    /// This can be negative unlike [`year_div_100`](#structfield.year_div_100)
    /// and [`year_mod_100`](#structfield.year_mod_100) fields.
    pub year: Option<i32>,

    /// Year divided by 100. Implies that the year is >= 1 BCE when set.
    ///
    /// Due to the common usage, if this field is missing but
    /// [`year_mod_100`](#structfield.year_mod_100) is present,
    /// it is inferred to 19 when `year_mod_100 >= 70` and 20 otherwise.
    pub year_div_100: Option<i32>,

    /// Year modulo 100. Implies that the year is >= 1 BCE when set.
    pub year_mod_100: Option<i32>,

    /// Year in the [ISO week date](../naive/struct.NaiveDate.html#week-date).
    ///
    /// This can be negative unlike [`isoyear_div_100`](#structfield.isoyear_div_100) and
    /// [`isoyear_mod_100`](#structfield.isoyear_mod_100) fields.
    pub isoyear: Option<i32>,

    /// Year in the [ISO week date](../naive/struct.NaiveDate.html#week-date), divided by 100.
    /// Implies that the year is >= 1 BCE when set.
    ///
    /// Due to the common usage, if this field is missing but
    /// [`isoyear_mod_100`](#structfield.isoyear_mod_100) is present,
    /// it is inferred to 19 when `isoyear_mod_100 >= 70` and 20 otherwise.
    pub isoyear_div_100: Option<i32>,

    /// Year in the [ISO week date](../naive/struct.NaiveDate.html#week-date), modulo 100.
    /// Implies that the year is >= 1 BCE when set.
    pub isoyear_mod_100: Option<i32>,

    /// Month (1--12).
    pub month: Option<u32>,

    /// Week number, where the week 1 starts at the first Sunday of January
    /// (0--53, 1--53 or 1--52 depending on the year).
    pub week_from_sun: Option<u32>,

    /// Week number, where the week 1 starts at the first Monday of January
    /// (0--53, 1--53 or 1--52 depending on the year).
    pub week_from_mon: Option<u32>,

    /// [ISO week number](../naive/struct.NaiveDate.html#week-date)
    /// (1--52 or 1--53 depending on the year).
    pub isoweek: Option<u32>,

    /// Day of the week.
    pub weekday: Option<Weekday>,

    /// Day of the year (1--365 or 1--366 depending on the year).
    pub ordinal: Option<u32>,

    /// Day of the month (1--28, 1--29, 1--30 or 1--31 depending on the month).
    pub day: Option<u32>,

    /// Hour number divided by 12 (0--1). 0 indicates AM and 1 indicates PM.
    pub hour_div_12: Option<u32>,

    /// Hour number modulo 12 (0--11).
    pub hour_mod_12: Option<u32>,

    /// Minute number (0--59).
    pub minute: Option<u32>,

    /// Second number (0--60, accounting for leap seconds).
    pub second: Option<u32>,

    /// The number of nanoseconds since the whole second (0--999,999,999).
    pub nanosecond: Option<u32>,

    /// The number of non-leap seconds since the midnight UTC on January 1, 1970.
    ///
    /// This can be off by one if [`second`](#structfield.second) is 60 (a leap second).
    pub timestamp: Option<i64>,

    /// Offset from the local time to UTC, in seconds.
    pub offset: Option<i32>,

    /// A dummy field to make this type not fully destructible (required for API stability).
    _dummy: (),
}

/// Checks if `old` is either empty or has the same value as `new` (i.e. "consistent"),
/// and if it is empty, set `old` to `new` as well.
#[inline]
fn set_if_consistent<T: PartialEq>(old: &mut Option<T>, new: T) -> ParseResult<()> {
    if let Some(ref old) = *old {
        if *old == new {
            Ok(())
        } else {
            Err(IMPOSSIBLE)
        }
    } else {
        *old = Some(new);
        Ok(())
    }
}

impl Parsed {
    /// Returns the initial value of parsed parts.
    pub fn new() -> Parsed {
        Parsed::default()
    }

    /// Tries to set the [`year`](#structfield.year) field from given value.
    #[inline]
    pub fn set_year(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.year, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`year_div_100`](#structfield.year_div_100) field from given value.
    #[inline]
    pub fn set_year_div_100(&mut self, value: i64) -> ParseResult<()> {
        if value < 0 {
            return Err(OUT_OF_RANGE);
        }
        set_if_consistent(&mut self.year_div_100, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`year_mod_100`](#structfield.year_mod_100) field from given value.
    #[inline]
    pub fn set_year_mod_100(&mut self, value: i64) -> ParseResult<()> {
        if value < 0 {
            return Err(OUT_OF_RANGE);
        }
        set_if_consistent(&mut self.year_mod_100, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`isoyear`](#structfield.isoyear) field from given value.
    #[inline]
    pub fn set_isoyear(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.isoyear, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`isoyear_div_100`](#structfield.isoyear_div_100) field from given value.
    #[inline]
    pub fn set_isoyear_div_100(&mut self, value: i64) -> ParseResult<()> {
        if value < 0 {
            return Err(OUT_OF_RANGE);
        }
        set_if_consistent(&mut self.isoyear_div_100, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`isoyear_mod_100`](#structfield.isoyear_mod_100) field from given value.
    #[inline]
    pub fn set_isoyear_mod_100(&mut self, value: i64) -> ParseResult<()> {
        if value < 0 {
            return Err(OUT_OF_RANGE);
        }
        set_if_consistent(&mut self.isoyear_mod_100, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`month`](#structfield.month) field from given value.
    #[inline]
    pub fn set_month(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.month, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`week_from_sun`](#structfield.week_from_sun) field from given value.
    #[inline]
    pub fn set_week_from_sun(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.week_from_sun, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`week_from_mon`](#structfield.week_from_mon) field from given value.
    #[inline]
    pub fn set_week_from_mon(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.week_from_mon, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`isoweek`](#structfield.isoweek) field from given value.
    #[inline]
    pub fn set_isoweek(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.isoweek, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`weekday`](#structfield.weekday) field from given value.
    #[inline]
    pub fn set_weekday(&mut self, value: Weekday) -> ParseResult<()> {
        set_if_consistent(&mut self.weekday, value)
    }

    /// Tries to set the [`ordinal`](#structfield.ordinal) field from given value.
    #[inline]
    pub fn set_ordinal(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.ordinal, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`day`](#structfield.day) field from given value.
    #[inline]
    pub fn set_day(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.day, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`hour_div_12`](#structfield.hour_div_12) field from given value.
    /// (`false` for AM, `true` for PM)
    #[inline]
    pub fn set_ampm(&mut self, value: bool) -> ParseResult<()> {
        set_if_consistent(&mut self.hour_div_12, if value { 1 } else { 0 })
    }

    /// Tries to set the [`hour_mod_12`](#structfield.hour_mod_12) field from
    /// given hour number in 12-hour clocks.
    #[inline]
    pub fn set_hour12(&mut self, value: i64) -> ParseResult<()> {
        if !(1..=12).contains(&value) {
            return Err(OUT_OF_RANGE);
        }
        set_if_consistent(&mut self.hour_mod_12, value as u32 % 12)
    }

    /// Tries to set both [`hour_div_12`](#structfield.hour_div_12) and
    /// [`hour_mod_12`](#structfield.hour_mod_12) fields from given value.
    #[inline]
    pub fn set_hour(&mut self, value: i64) -> ParseResult<()> {
        let v = value.to_u32().ok_or(OUT_OF_RANGE)?;
        set_if_consistent(&mut self.hour_div_12, v / 12)?;
        set_if_consistent(&mut self.hour_mod_12, v % 12)?;
        Ok(())
    }

    /// Tries to set the [`minute`](#structfield.minute) field from given value.
    #[inline]
    pub fn set_minute(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.minute, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`second`](#structfield.second) field from given value.
    #[inline]
    pub fn set_second(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.second, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`nanosecond`](#structfield.nanosecond) field from given value.
    #[inline]
    pub fn set_nanosecond(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.nanosecond, value.to_u32().ok_or(OUT_OF_RANGE)?)
    }

    /// Tries to set the [`timestamp`](#structfield.timestamp) field from given value.
    #[inline]
    pub fn set_timestamp(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.timestamp, value)
    }

    /// Tries to set the [`offset`](#structfield.offset) field from given value.
    #[inline]
    pub fn set_offset(&mut self, value: i64) -> ParseResult<()> {
        set_if_consistent(&mut self.offset, value.to_i32().ok_or(OUT_OF_RANGE)?)
    }

    /// Returns a parsed naive date out of given fields.
    ///
    /// This method is able to determine the date from given subset of fields:
    ///
    /// - Year, month, day.
    /// - Year, day of the year (ordinal).
    /// - Year, week number counted from Sunday or Monday, day of the week.
    /// - ISO week date.
    ///
    /// Gregorian year and ISO week date year can have their century number (`*_div_100`) omitted,
    /// the two-digit year is used to guess the century number then.
    pub fn to_naive_date(&self) -> ParseResult<NaiveDate> {
        fn resolve_year(
            y: Option<i32>,
            q: Option<i32>,
            r: Option<i32>,
        ) -> ParseResult<Option<i32>> {
            match (y, q, r) {
                // if there is no further information, simply return the given full year.
                // this is a common case, so let's avoid division here.
                (y, None, None) => Ok(y),

                // if there is a full year *and* also quotient and/or modulo,
                // check if present quotient and/or modulo is consistent to the full year.
                // since the presence of those fields means a positive full year,
                // we should filter a negative full year first.
                (Some(y), q, r @ Some(0..=99)) | (Some(y), q, r @ None) => {
                    if y < 0 {
                        return Err(OUT_OF_RANGE);
                    }
                    let (q_, r_) = div_rem(y, 100);
                    if q.unwrap_or(q_) == q_ && r.unwrap_or(r_) == r_ {
                        Ok(Some(y))
                    } else {
                        Err(IMPOSSIBLE)
                    }
                }

                // the full year is missing but we have quotient and modulo.
                // reconstruct the full year. make sure that the result is always positive.
                (None, Some(q), Some(r @ 0..=99)) => {
                    if q < 0 {
                        return Err(OUT_OF_RANGE);
                    }
                    let y = q.checked_mul(100).and_then(|v| v.checked_add(r));
                    Ok(Some(y.ok_or(OUT_OF_RANGE)?))
                }

                // we only have modulo. try to interpret a modulo as a conventional two-digit year.
                // note: we are affected by Rust issue #18060. avoid multiple range patterns.
                (None, None, Some(r @ 0..=99)) => Ok(Some(r + if r < 70 { 2000 } else { 1900 })),

                // otherwise it is an out-of-bound or insufficient condition.
                (None, Some(_), None) => Err(NOT_ENOUGH),
                (_, _, Some(_)) => Err(OUT_OF_RANGE),
            }
        }

        let given_year = resolve_year(self.year, self.year_div_100, self.year_mod_100)?;
        let given_isoyear = resolve_year(self.isoyear, self.isoyear_div_100, self.isoyear_mod_100)?;

        // verify the normal year-month-day date.
        let verify_ymd = |date: NaiveDate| {
            let year = date.year();
            let (year_div_100, year_mod_100) = if year >= 0 {
                let (q, r) = div_rem(year, 100);
                (Some(q), Some(r))
            } else {
                (None, None) // they should be empty to be consistent
            };
            let month = date.month();
            let day = date.day();
            self.year.unwrap_or(year) == year
                && self.year_div_100.or(year_div_100) == year_div_100
                && self.year_mod_100.or(year_mod_100) == year_mod_100
                && self.month.unwrap_or(month) == month
                && self.day.unwrap_or(day) == day
        };

        // verify the ISO week date.
        let verify_isoweekdate = |date: NaiveDate| {
            let week = date.iso_week();
            let isoyear = week.year();
            let isoweek = week.week();
            let weekday = date.weekday();
            let (isoyear_div_100, isoyear_mod_100) = if isoyear >= 0 {
                let (q, r) = div_rem(isoyear, 100);
                (Some(q), Some(r))
            } else {
                (None, None) // they should be empty to be consistent
            };
            self.isoyear.unwrap_or(isoyear) == isoyear
                && self.isoyear_div_100.or(isoyear_div_100) == isoyear_div_100
                && self.isoyear_mod_100.or(isoyear_mod_100) == isoyear_mod_100
                && self.isoweek.unwrap_or(isoweek) == isoweek
                && self.weekday.unwrap_or(weekday) == weekday
        };

        // verify the ordinal and other (non-ISO) week dates.
        let verify_ordinal = |date: NaiveDate| {
            let ordinal = date.ordinal();
            let weekday = date.weekday();
            let week_from_sun = (ordinal as i32 - weekday.num_days_from_sunday() as i32 + 7) / 7;
            let week_from_mon = (ordinal as i32 - weekday.num_days_from_monday() as i32 + 7) / 7;
            self.ordinal.unwrap_or(ordinal) == ordinal
                && self.week_from_sun.map_or(week_from_sun, |v| v as i32) == week_from_sun
                && self.week_from_mon.map_or(week_from_mon, |v| v as i32) == week_from_mon
        };

        // test several possibilities.
        // tries to construct a full `NaiveDate` as much as possible, then verifies that
        // it is consistent with other given fields.
        let (verified, parsed_date) = match (given_year, given_isoyear, self) {
            (Some(year), _, &Parsed { month: Some(month), day: Some(day), .. }) => {
                // year, month, day
                let date = NaiveDate::from_ymd_opt(year, month, day).ok_or(OUT_OF_RANGE)?;
                (verify_isoweekdate(date) && verify_ordinal(date), date)
            }

            (Some(year), _, &Parsed { ordinal: Some(ordinal), .. }) => {
                // year, day of the year
                let date = NaiveDate::from_yo_opt(year, ordinal).ok_or(OUT_OF_RANGE)?;
                (verify_ymd(date) && verify_isoweekdate(date) && verify_ordinal(date), date)
            }

            (
                Some(year),
                _,
                &Parsed { week_from_sun: Some(week_from_sun), weekday: Some(weekday), .. },
            ) => {
                // year, week (starting at 1st Sunday), day of the week
                let newyear = NaiveDate::from_yo_opt(year, 1).ok_or(OUT_OF_RANGE)?;
                let firstweek = match newyear.weekday() {
                    Weekday::Sun => 0,
                    Weekday::Mon => 6,
                    Weekday::Tue => 5,
                    Weekday::Wed => 4,
                    Weekday::Thu => 3,
                    Weekday::Fri => 2,
                    Weekday::Sat => 1,
                };

                // `firstweek+1`-th day of January is the beginning of the week 1.
                if week_from_sun > 53 {
                    return Err(OUT_OF_RANGE);
                } // can it overflow?
                let ndays = firstweek
                    + (week_from_sun as i32 - 1) * 7
                    + weekday.num_days_from_sunday() as i32;
                let date = newyear
                    .checked_add_signed(OldDuration::days(i64::from(ndays)))
                    .ok_or(OUT_OF_RANGE)?;
                if date.year() != year {
                    return Err(OUT_OF_RANGE);
                } // early exit for correct error

                (verify_ymd(date) && verify_isoweekdate(date) && verify_ordinal(date), date)
            }

            (
                Some(year),
                _,
                &Parsed { week_from_mon: Some(week_from_mon), weekday: Some(weekday), .. },
            ) => {
                // year, week (starting at 1st Monday), day of the week
                let newyear = NaiveDate::from_yo_opt(year, 1).ok_or(OUT_OF_RANGE)?;
                let firstweek = match newyear.weekday() {
                    Weekday::Sun => 1,
                    Weekday::Mon => 0,
                    Weekday::Tue => 6,
                    Weekday::Wed => 5,
                    Weekday::Thu => 4,
                    Weekday::Fri => 3,
                    Weekday::Sat => 2,
                };

                // `firstweek+1`-th day of January is the beginning of the week 1.
                if week_from_mon > 53 {
                    return Err(OUT_OF_RANGE);
                } // can it overflow?
                let ndays = firstweek
                    + (week_from_mon as i32 - 1) * 7
                    + weekday.num_days_from_monday() as i32;
                let date = newyear
                    .checked_add_signed(OldDuration::days(i64::from(ndays)))
                    .ok_or(OUT_OF_RANGE)?;
                if date.year() != year {
                    return Err(OUT_OF_RANGE);
                } // early exit for correct error

                (verify_ymd(date) && verify_isoweekdate(date) && verify_ordinal(date), date)
            }

            (_, Some(isoyear), &Parsed { isoweek: Some(isoweek), weekday: Some(weekday), .. }) => {
                // ISO year, week, day of the week
                let date = NaiveDate::from_isoywd_opt(isoyear, isoweek, weekday);
                let date = date.ok_or(OUT_OF_RANGE)?;
                (verify_ymd(date) && verify_ordinal(date), date)
            }

            (_, _, _) => return Err(NOT_ENOUGH),
        };

        if verified {
            Ok(parsed_date)
        } else {
            Err(IMPOSSIBLE)
        }
    }

    /// Returns a parsed naive time out of given fields.
    ///
    /// This method is able to determine the time from given subset of fields:
    ///
    /// - Hour, minute. (second and nanosecond assumed to be 0)
    /// - Hour, minute, second. (nanosecond assumed to be 0)
    /// - Hour, minute, second, nanosecond.
    ///
    /// It is able to handle leap seconds when given second is 60.
    pub fn to_naive_time(&self) -> ParseResult<NaiveTime> {
        let hour_div_12 = match self.hour_div_12 {
            Some(v @ 0..=1) => v,
            Some(_) => return Err(OUT_OF_RANGE),
            None => return Err(NOT_ENOUGH),
        };
        let hour_mod_12 = match self.hour_mod_12 {
            Some(v @ 0..=11) => v,
            Some(_) => return Err(OUT_OF_RANGE),
            None => return Err(NOT_ENOUGH),
        };
        let hour = hour_div_12 * 12 + hour_mod_12;

        let minute = match self.minute {
            Some(v @ 0..=59) => v,
            Some(_) => return Err(OUT_OF_RANGE),
            None => return Err(NOT_ENOUGH),
        };

        // we allow omitting seconds or nanoseconds, but they should be in the range.
        let (second, mut nano) = match self.second.unwrap_or(0) {
            v @ 0..=59 => (v, 0),
            60 => (59, 1_000_000_000),
            _ => return Err(OUT_OF_RANGE),
        };
        nano += match self.nanosecond {
            Some(v @ 0..=999_999_999) if self.second.is_some() => v,
            Some(0..=999_999_999) => return Err(NOT_ENOUGH), // second is missing
            Some(_) => return Err(OUT_OF_RANGE),
            None => 0,
        };

        NaiveTime::from_hms_nano_opt(hour, minute, second, nano).ok_or(OUT_OF_RANGE)
    }

    /// Returns a parsed naive date and time out of given fields,
    /// except for the [`offset`](#structfield.offset) field (assumed to have a given value).
    /// This is required for parsing a local time or other known-timezone inputs.
    ///
    /// This method is able to determine the combined date and time
    /// from date and time fields or a single [`timestamp`](#structfield.timestamp) field.
    /// Either way those fields have to be consistent to each other.
    pub fn to_naive_datetime_with_offset(&self, offset: i32) -> ParseResult<NaiveDateTime> {
        let date = self.to_naive_date();
        let time = self.to_naive_time();
        if let (Ok(date), Ok(time)) = (date, time) {
            let datetime = date.and_time(time);

            // verify the timestamp field if any
            // the following is safe, `timestamp` is very limited in range
            let timestamp = datetime.timestamp() - i64::from(offset);
            if let Some(given_timestamp) = self.timestamp {
                // if `datetime` represents a leap second, it might be off by one second.
                if given_timestamp != timestamp
                    && !(datetime.nanosecond() >= 1_000_000_000 && given_timestamp == timestamp + 1)
                {
                    return Err(IMPOSSIBLE);
                }
            }

            Ok(datetime)
        } else if let Some(timestamp) = self.timestamp {
            use super::ParseError as PE;
            use super::ParseErrorKind::{Impossible, OutOfRange};

            // if date and time is problematic already, there is no point proceeding.
            // we at least try to give a correct error though.
            match (date, time) {
                (Err(PE(OutOfRange)), _) | (_, Err(PE(OutOfRange))) => return Err(OUT_OF_RANGE),
                (Err(PE(Impossible)), _) | (_, Err(PE(Impossible))) => return Err(IMPOSSIBLE),
                (_, _) => {} // one of them is insufficient
            }

            // reconstruct date and time fields from timestamp
            let ts = timestamp.checked_add(i64::from(offset)).ok_or(OUT_OF_RANGE)?;
            let datetime = NaiveDateTime::from_timestamp_opt(ts, 0);
            let mut datetime = datetime.ok_or(OUT_OF_RANGE)?;

            // fill year, ordinal, hour, minute and second fields from timestamp.
            // if existing fields are consistent, this will allow the full date/time reconstruction.
            let mut parsed = self.clone();
            if parsed.second == Some(60) {
                // `datetime.second()` cannot be 60, so this is the only case for a leap second.
                match datetime.second() {
                    // it's okay, just do not try to overwrite the existing field.
                    59 => {}
                    // `datetime` is known to be off by one second.
                    0 => {
                        datetime -= OldDuration::seconds(1);
                    }
                    // otherwise it is impossible.
                    _ => return Err(IMPOSSIBLE),
                }
            // ...and we have the correct candidates for other fields.
            } else {
                parsed.set_second(i64::from(datetime.second()))?;
            }
            parsed.set_year(i64::from(datetime.year()))?;
            parsed.set_ordinal(i64::from(datetime.ordinal()))?; // more efficient than ymd
            parsed.set_hour(i64::from(datetime.hour()))?;
            parsed.set_minute(i64::from(datetime.minute()))?;

            // validate other fields (e.g. week) and return
            let date = parsed.to_naive_date()?;
            let time = parsed.to_naive_time()?;
            Ok(date.and_time(time))
        } else {
            // reproduce the previous error(s)
            date?;
            time?;
            unreachable!()
        }
    }

    /// Returns a parsed fixed time zone offset out of given fields.
    pub fn to_fixed_offset(&self) -> ParseResult<FixedOffset> {
        self.offset.and_then(FixedOffset::east_opt).ok_or(OUT_OF_RANGE)
    }

    /// Returns a parsed timezone-aware date and time out of given fields.
    ///
    /// This method is able to determine the combined date and time
    /// from date and time fields or a single [`timestamp`](#structfield.timestamp) field,
    /// plus a time zone offset.
    /// Either way those fields have to be consistent to each other.
    pub fn to_datetime(&self) -> ParseResult<DateTime<FixedOffset>> {
        let offset = self.offset.ok_or(NOT_ENOUGH)?;
        let datetime = self.to_naive_datetime_with_offset(offset)?;
        let offset = FixedOffset::east_opt(offset).ok_or(OUT_OF_RANGE)?;

        // this is used to prevent an overflow when calling FixedOffset::from_local_datetime
        datetime
            .checked_sub_signed(OldDuration::seconds(i64::from(offset.local_minus_utc())))
            .ok_or(OUT_OF_RANGE)?;

        match offset.from_local_datetime(&datetime) {
            LocalResult::None => Err(IMPOSSIBLE),
            LocalResult::Single(t) => Ok(t),
            LocalResult::Ambiguous(..) => Err(NOT_ENOUGH),
        }
    }

    /// Returns a parsed timezone-aware date and time out of given fields,
    /// with an additional `TimeZone` used to interpret and validate the local date.
    ///
    /// This method is able to determine the combined date and time
    /// from date and time fields or a single [`timestamp`](#structfield.timestamp) field,
    /// plus a time zone offset.
    /// Either way those fields have to be consistent to each other.
    /// If parsed fields include an UTC offset, it also has to be consistent to
    /// [`offset`](#structfield.offset).
    pub fn to_datetime_with_timezone<Tz: TimeZone>(&self, tz: &Tz) -> ParseResult<DateTime<Tz>> {
        // if we have `timestamp` specified, guess an offset from that.
        let mut guessed_offset = 0;
        if let Some(timestamp) = self.timestamp {
            // make a naive `DateTime` from given timestamp and (if any) nanosecond.
            // an empty `nanosecond` is always equal to zero, so missing nanosecond is fine.
            let nanosecond = self.nanosecond.unwrap_or(0);
            let dt = NaiveDateTime::from_timestamp_opt(timestamp, nanosecond);
            let dt = dt.ok_or(OUT_OF_RANGE)?;
            guessed_offset = tz.offset_from_utc_datetime(&dt).fix().local_minus_utc();
        }

        // checks if the given `DateTime` has a consistent `Offset` with given `self.offset`.
        let check_offset = |dt: &DateTime<Tz>| {
            if let Some(offset) = self.offset {
                dt.offset().fix().local_minus_utc() == offset
            } else {
                true
            }
        };

        // `guessed_offset` should be correct when `self.timestamp` is given.
        // it will be 0 otherwise, but this is fine as the algorithm ignores offset for that case.
        let datetime = self.to_naive_datetime_with_offset(guessed_offset)?;
        match tz.from_local_datetime(&datetime) {
            LocalResult::None => Err(IMPOSSIBLE),
            LocalResult::Single(t) => {
                if check_offset(&t) {
                    Ok(t)
                } else {
                    Err(IMPOSSIBLE)
                }
            }
            LocalResult::Ambiguous(min, max) => {
                // try to disambiguate two possible local dates by offset.
                match (check_offset(&min), check_offset(&max)) {
                    (false, false) => Err(IMPOSSIBLE),
                    (false, true) => Ok(max),
                    (true, false) => Ok(min),
                    (true, true) => Err(NOT_ENOUGH),
                }
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::super::{IMPOSSIBLE, NOT_ENOUGH, OUT_OF_RANGE};
    use super::Parsed;
    use crate::naive::{NaiveDate, NaiveTime};
    use crate::offset::{FixedOffset, TimeZone, Utc};
    use crate::Datelike;
    use crate::Weekday::*;

    #[test]
    fn test_parsed_set_fields() {
        // year*, isoyear*
        let mut p = Parsed::new();
        assert_eq!(p.set_year(1987), Ok(()));
        assert_eq!(p.set_year(1986), Err(IMPOSSIBLE));
        assert_eq!(p.set_year(1988), Err(IMPOSSIBLE));
        assert_eq!(p.set_year(1987), Ok(()));
        assert_eq!(p.set_year_div_100(20), Ok(())); // independent to `year`
        assert_eq!(p.set_year_div_100(21), Err(IMPOSSIBLE));
        assert_eq!(p.set_year_div_100(19), Err(IMPOSSIBLE));
        assert_eq!(p.set_year_mod_100(37), Ok(())); // ditto
        assert_eq!(p.set_year_mod_100(38), Err(IMPOSSIBLE));
        assert_eq!(p.set_year_mod_100(36), Err(IMPOSSIBLE));

        let mut p = Parsed::new();
        assert_eq!(p.set_year(0), Ok(()));
        assert_eq!(p.set_year_div_100(0), Ok(()));
        assert_eq!(p.set_year_mod_100(0), Ok(()));

        let mut p = Parsed::new();
        assert_eq!(p.set_year_div_100(-1), Err(OUT_OF_RANGE));
        assert_eq!(p.set_year_mod_100(-1), Err(OUT_OF_RANGE));
        assert_eq!(p.set_year(-1), Ok(()));
        assert_eq!(p.set_year(-2), Err(IMPOSSIBLE));
        assert_eq!(p.set_year(0), Err(IMPOSSIBLE));

        let mut p = Parsed::new();
        assert_eq!(p.set_year_div_100(0x1_0000_0008), Err(OUT_OF_RANGE));
        assert_eq!(p.set_year_div_100(8), Ok(()));
        assert_eq!(p.set_year_div_100(0x1_0000_0008), Err(OUT_OF_RANGE));

        // month, week*, isoweek, ordinal, day, minute, second, nanosecond, offset
        let mut p = Parsed::new();
        assert_eq!(p.set_month(7), Ok(()));
        assert_eq!(p.set_month(1), Err(IMPOSSIBLE));
        assert_eq!(p.set_month(6), Err(IMPOSSIBLE));
        assert_eq!(p.set_month(8), Err(IMPOSSIBLE));
        assert_eq!(p.set_month(12), Err(IMPOSSIBLE));

        let mut p = Parsed::new();
        assert_eq!(p.set_month(8), Ok(()));
        assert_eq!(p.set_month(0x1_0000_0008), Err(OUT_OF_RANGE));

        // hour
        let mut p = Parsed::new();
        assert_eq!(p.set_hour(12), Ok(()));
        assert_eq!(p.set_hour(11), Err(IMPOSSIBLE));
        assert_eq!(p.set_hour(13), Err(IMPOSSIBLE));
        assert_eq!(p.set_hour(12), Ok(()));
        assert_eq!(p.set_ampm(false), Err(IMPOSSIBLE));
        assert_eq!(p.set_ampm(true), Ok(()));
        assert_eq!(p.set_hour12(12), Ok(()));
        assert_eq!(p.set_hour12(0), Err(OUT_OF_RANGE)); // requires canonical representation
        assert_eq!(p.set_hour12(1), Err(IMPOSSIBLE));
        assert_eq!(p.set_hour12(11), Err(IMPOSSIBLE));

        let mut p = Parsed::new();
        assert_eq!(p.set_ampm(true), Ok(()));
        assert_eq!(p.set_hour12(7), Ok(()));
        assert_eq!(p.set_hour(7), Err(IMPOSSIBLE));
        assert_eq!(p.set_hour(18), Err(IMPOSSIBLE));
        assert_eq!(p.set_hour(19), Ok(()));

        // timestamp
        let mut p = Parsed::new();
        assert_eq!(p.set_timestamp(1_234_567_890), Ok(()));
        assert_eq!(p.set_timestamp(1_234_567_889), Err(IMPOSSIBLE));
        assert_eq!(p.set_timestamp(1_234_567_891), Err(IMPOSSIBLE));
    }

    #[test]
    fn test_parsed_to_naive_date() {
        macro_rules! parse {
            ($($k:ident: $v:expr),*) => (
                Parsed { $($k: Some($v),)* ..Parsed::new() }.to_naive_date()
            )
        }

        let ymd = |y, m, d| Ok(NaiveDate::from_ymd(y, m, d));

        // ymd: omission of fields
        assert_eq!(parse!(), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 1984), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 1984, month: 1), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 1984, month: 1, day: 2), ymd(1984, 1, 2));
        assert_eq!(parse!(year: 1984, day: 2), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_div_100: 19), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_div_100: 19, year_mod_100: 84), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_div_100: 19, year_mod_100: 84, month: 1), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_div_100: 19, year_mod_100: 84, month: 1, day: 2), ymd(1984, 1, 2));
        assert_eq!(parse!(year_div_100: 19, year_mod_100: 84, day: 2), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_div_100: 19, month: 1, day: 2), Err(NOT_ENOUGH));
        assert_eq!(parse!(year_mod_100: 70, month: 1, day: 2), ymd(1970, 1, 2));
        assert_eq!(parse!(year_mod_100: 69, month: 1, day: 2), ymd(2069, 1, 2));

        // ymd: out-of-range conditions
        assert_eq!(parse!(year_div_100: 19, year_mod_100: 84, month: 2, day: 29), ymd(1984, 2, 29));
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 83, month: 2, day: 29),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 83, month: 13, day: 1),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 83, month: 12, day: 31),
            ymd(1983, 12, 31)
        );
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 83, month: 12, day: 32),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 83, month: 12, day: 0),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year_div_100: 19, year_mod_100: 100, month: 1, day: 1),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(parse!(year_div_100: 19, year_mod_100: -1, month: 1, day: 1), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year_div_100: 0, year_mod_100: 0, month: 1, day: 1), ymd(0, 1, 1));
        assert_eq!(parse!(year_div_100: -1, year_mod_100: 42, month: 1, day: 1), Err(OUT_OF_RANGE));
        let max_year = NaiveDate::MAX.year();
        assert_eq!(
            parse!(year_div_100: max_year / 100,
                          year_mod_100: max_year % 100, month: 1, day: 1),
            ymd(max_year, 1, 1)
        );
        assert_eq!(
            parse!(year_div_100: (max_year + 1) / 100,
                          year_mod_100: (max_year + 1) % 100, month: 1, day: 1),
            Err(OUT_OF_RANGE)
        );

        // ymd: conflicting inputs
        assert_eq!(parse!(year: 1984, year_div_100: 19, month: 1, day: 1), ymd(1984, 1, 1));
        assert_eq!(parse!(year: 1984, year_div_100: 20, month: 1, day: 1), Err(IMPOSSIBLE));
        assert_eq!(parse!(year: 1984, year_mod_100: 84, month: 1, day: 1), ymd(1984, 1, 1));
        assert_eq!(parse!(year: 1984, year_mod_100: 83, month: 1, day: 1), Err(IMPOSSIBLE));
        assert_eq!(
            parse!(year: 1984, year_div_100: 19, year_mod_100: 84, month: 1, day: 1),
            ymd(1984, 1, 1)
        );
        assert_eq!(
            parse!(year: 1984, year_div_100: 18, year_mod_100: 94, month: 1, day: 1),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(year: 1984, year_div_100: 18, year_mod_100: 184, month: 1, day: 1),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year: -1, year_div_100: 0, year_mod_100: -1, month: 1, day: 1),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(year: -1, year_div_100: -1, year_mod_100: 99, month: 1, day: 1),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(parse!(year: -1, year_div_100: 0, month: 1, day: 1), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: -1, year_mod_100: 99, month: 1, day: 1), Err(OUT_OF_RANGE));

        // weekdates
        assert_eq!(parse!(year: 2000, week_from_mon: 0), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 2000, week_from_sun: 0), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 2000, weekday: Sun), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 2000, week_from_mon: 0, weekday: Fri), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2000, week_from_sun: 0, weekday: Fri), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2000, week_from_mon: 0, weekday: Sat), ymd(2000, 1, 1));
        assert_eq!(parse!(year: 2000, week_from_sun: 0, weekday: Sat), ymd(2000, 1, 1));
        assert_eq!(parse!(year: 2000, week_from_mon: 0, weekday: Sun), ymd(2000, 1, 2));
        assert_eq!(parse!(year: 2000, week_from_sun: 1, weekday: Sun), ymd(2000, 1, 2));
        assert_eq!(parse!(year: 2000, week_from_mon: 1, weekday: Mon), ymd(2000, 1, 3));
        assert_eq!(parse!(year: 2000, week_from_sun: 1, weekday: Mon), ymd(2000, 1, 3));
        assert_eq!(parse!(year: 2000, week_from_mon: 1, weekday: Sat), ymd(2000, 1, 8));
        assert_eq!(parse!(year: 2000, week_from_sun: 1, weekday: Sat), ymd(2000, 1, 8));
        assert_eq!(parse!(year: 2000, week_from_mon: 1, weekday: Sun), ymd(2000, 1, 9));
        assert_eq!(parse!(year: 2000, week_from_sun: 2, weekday: Sun), ymd(2000, 1, 9));
        assert_eq!(parse!(year: 2000, week_from_mon: 2, weekday: Mon), ymd(2000, 1, 10));
        assert_eq!(parse!(year: 2000, week_from_sun: 52, weekday: Sat), ymd(2000, 12, 30));
        assert_eq!(parse!(year: 2000, week_from_sun: 53, weekday: Sun), ymd(2000, 12, 31));
        assert_eq!(parse!(year: 2000, week_from_sun: 53, weekday: Mon), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2000, week_from_sun: 0xffffffff, weekday: Mon), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2006, week_from_sun: 0, weekday: Sat), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2006, week_from_sun: 1, weekday: Sun), ymd(2006, 1, 1));

        // weekdates: conflicting inputs
        assert_eq!(
            parse!(year: 2000, week_from_mon: 1, week_from_sun: 1, weekday: Sat),
            ymd(2000, 1, 8)
        );
        assert_eq!(
            parse!(year: 2000, week_from_mon: 1, week_from_sun: 2, weekday: Sun),
            ymd(2000, 1, 9)
        );
        assert_eq!(
            parse!(year: 2000, week_from_mon: 1, week_from_sun: 1, weekday: Sun),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(year: 2000, week_from_mon: 2, week_from_sun: 2, weekday: Sun),
            Err(IMPOSSIBLE)
        );

        // ISO weekdates
        assert_eq!(parse!(isoyear: 2004, isoweek: 53), Err(NOT_ENOUGH));
        assert_eq!(parse!(isoyear: 2004, isoweek: 53, weekday: Fri), ymd(2004, 12, 31));
        assert_eq!(parse!(isoyear: 2004, isoweek: 53, weekday: Sat), ymd(2005, 1, 1));
        assert_eq!(parse!(isoyear: 2004, isoweek: 0xffffffff, weekday: Sat), Err(OUT_OF_RANGE));
        assert_eq!(parse!(isoyear: 2005, isoweek: 0, weekday: Thu), Err(OUT_OF_RANGE));
        assert_eq!(parse!(isoyear: 2005, isoweek: 5, weekday: Thu), ymd(2005, 2, 3));
        assert_eq!(parse!(isoyear: 2005, weekday: Thu), Err(NOT_ENOUGH));

        // year and ordinal
        assert_eq!(parse!(ordinal: 123), Err(NOT_ENOUGH));
        assert_eq!(parse!(year: 2000, ordinal: 0), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2000, ordinal: 1), ymd(2000, 1, 1));
        assert_eq!(parse!(year: 2000, ordinal: 60), ymd(2000, 2, 29));
        assert_eq!(parse!(year: 2000, ordinal: 61), ymd(2000, 3, 1));
        assert_eq!(parse!(year: 2000, ordinal: 366), ymd(2000, 12, 31));
        assert_eq!(parse!(year: 2000, ordinal: 367), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2000, ordinal: 0xffffffff), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2100, ordinal: 0), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2100, ordinal: 1), ymd(2100, 1, 1));
        assert_eq!(parse!(year: 2100, ordinal: 59), ymd(2100, 2, 28));
        assert_eq!(parse!(year: 2100, ordinal: 60), ymd(2100, 3, 1));
        assert_eq!(parse!(year: 2100, ordinal: 365), ymd(2100, 12, 31));
        assert_eq!(parse!(year: 2100, ordinal: 366), Err(OUT_OF_RANGE));
        assert_eq!(parse!(year: 2100, ordinal: 0xffffffff), Err(OUT_OF_RANGE));

        // more complex cases
        assert_eq!(
            parse!(year: 2014, month: 12, day: 31, ordinal: 365, isoyear: 2015, isoweek: 1,
                          week_from_sun: 52, week_from_mon: 52, weekday: Wed),
            ymd(2014, 12, 31)
        );
        assert_eq!(
            parse!(year: 2014, month: 12, ordinal: 365, isoyear: 2015, isoweek: 1,
                          week_from_sun: 52, week_from_mon: 52),
            ymd(2014, 12, 31)
        );
        assert_eq!(
            parse!(year: 2014, month: 12, day: 31, ordinal: 365, isoyear: 2014, isoweek: 53,
                          week_from_sun: 52, week_from_mon: 52, weekday: Wed),
            Err(IMPOSSIBLE)
        ); // no ISO week date 2014-W53-3
        assert_eq!(
            parse!(year: 2012, isoyear: 2015, isoweek: 1,
                          week_from_sun: 52, week_from_mon: 52),
            Err(NOT_ENOUGH)
        ); // ambiguous (2014-12-29, 2014-12-30, 2014-12-31)
        assert_eq!(parse!(year_div_100: 20, isoyear_mod_100: 15, ordinal: 366), Err(NOT_ENOUGH));
        // technically unique (2014-12-31) but Chrono gives up
    }

    #[test]
    fn test_parsed_to_naive_time() {
        macro_rules! parse {
            ($($k:ident: $v:expr),*) => (
                Parsed { $($k: Some($v),)* ..Parsed::new() }.to_naive_time()
            )
        }

        let hms = |h, m, s| Ok(NaiveTime::from_hms(h, m, s));
        let hmsn = |h, m, s, n| Ok(NaiveTime::from_hms_nano(h, m, s, n));

        // omission of fields
        assert_eq!(parse!(), Err(NOT_ENOUGH));
        assert_eq!(parse!(hour_div_12: 0), Err(NOT_ENOUGH));
        assert_eq!(parse!(hour_div_12: 0, hour_mod_12: 1), Err(NOT_ENOUGH));
        assert_eq!(parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23), hms(1, 23, 0));
        assert_eq!(parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 45), hms(1, 23, 45));
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 45,
                          nanosecond: 678_901_234),
            hmsn(1, 23, 45, 678_901_234)
        );
        assert_eq!(parse!(hour_div_12: 1, hour_mod_12: 11, minute: 45, second: 6), hms(23, 45, 6));
        assert_eq!(parse!(hour_mod_12: 1, minute: 23), Err(NOT_ENOUGH));
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, nanosecond: 456_789_012),
            Err(NOT_ENOUGH)
        );

        // out-of-range conditions
        assert_eq!(parse!(hour_div_12: 2, hour_mod_12: 0, minute: 0), Err(OUT_OF_RANGE));
        assert_eq!(parse!(hour_div_12: 1, hour_mod_12: 12, minute: 0), Err(OUT_OF_RANGE));
        assert_eq!(parse!(hour_div_12: 0, hour_mod_12: 1, minute: 60), Err(OUT_OF_RANGE));
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 61),
            Err(OUT_OF_RANGE)
        );
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 34,
                          nanosecond: 1_000_000_000),
            Err(OUT_OF_RANGE)
        );

        // leap seconds
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 60),
            hmsn(1, 23, 59, 1_000_000_000)
        );
        assert_eq!(
            parse!(hour_div_12: 0, hour_mod_12: 1, minute: 23, second: 60,
                          nanosecond: 999_999_999),
            hmsn(1, 23, 59, 1_999_999_999)
        );
    }

    #[test]
    fn test_parsed_to_naive_datetime_with_offset() {
        macro_rules! parse {
            (offset = $offset:expr; $($k:ident: $v:expr),*) => (
                Parsed { $($k: Some($v),)* ..Parsed::new() }.to_naive_datetime_with_offset($offset)
            );
            ($($k:ident: $v:expr),*) => (parse!(offset = 0; $($k: $v),*))
        }

        let ymdhms = |y, m, d, h, n, s| Ok(NaiveDate::from_ymd(y, m, d).and_hms(h, n, s));
        let ymdhmsn =
            |y, m, d, h, n, s, nano| Ok(NaiveDate::from_ymd(y, m, d).and_hms_nano(h, n, s, nano));

        // omission of fields
        assert_eq!(parse!(), Err(NOT_ENOUGH));
        assert_eq!(
            parse!(year: 2015, month: 1, day: 30,
                          hour_div_12: 1, hour_mod_12: 2, minute: 38),
            ymdhms(2015, 1, 30, 14, 38, 0)
        );
        assert_eq!(
            parse!(year: 1997, month: 1, day: 30,
                          hour_div_12: 1, hour_mod_12: 2, minute: 38, second: 5),
            ymdhms(1997, 1, 30, 14, 38, 5)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 34, hour_div_12: 0, hour_mod_12: 5,
                          minute: 6, second: 7, nanosecond: 890_123_456),
            ymdhmsn(2012, 2, 3, 5, 6, 7, 890_123_456)
        );
        assert_eq!(parse!(timestamp: 0), ymdhms(1970, 1, 1, 0, 0, 0));
        assert_eq!(parse!(timestamp: 1, nanosecond: 0), ymdhms(1970, 1, 1, 0, 0, 1));
        assert_eq!(parse!(timestamp: 1, nanosecond: 1), ymdhmsn(1970, 1, 1, 0, 0, 1, 1));
        assert_eq!(parse!(timestamp: 1_420_000_000), ymdhms(2014, 12, 31, 4, 26, 40));
        assert_eq!(parse!(timestamp: -0x1_0000_0000), ymdhms(1833, 11, 24, 17, 31, 44));

        // full fields
        assert_eq!(
            parse!(year: 2014, year_div_100: 20, year_mod_100: 14, month: 12, day: 31,
                          ordinal: 365, isoyear: 2015, isoyear_div_100: 20, isoyear_mod_100: 15,
                          isoweek: 1, week_from_sun: 52, week_from_mon: 52, weekday: Wed,
                          hour_div_12: 0, hour_mod_12: 4, minute: 26, second: 40,
                          nanosecond: 12_345_678, timestamp: 1_420_000_000),
            ymdhmsn(2014, 12, 31, 4, 26, 40, 12_345_678)
        );
        assert_eq!(
            parse!(year: 2014, year_div_100: 20, year_mod_100: 14, month: 12, day: 31,
                          ordinal: 365, isoyear: 2015, isoyear_div_100: 20, isoyear_mod_100: 15,
                          isoweek: 1, week_from_sun: 52, week_from_mon: 52, weekday: Wed,
                          hour_div_12: 0, hour_mod_12: 4, minute: 26, second: 40,
                          nanosecond: 12_345_678, timestamp: 1_419_999_999),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(offset = 32400;
                          year: 2014, year_div_100: 20, year_mod_100: 14, month: 12, day: 31,
                          ordinal: 365, isoyear: 2015, isoyear_div_100: 20, isoyear_mod_100: 15,
                          isoweek: 1, week_from_sun: 52, week_from_mon: 52, weekday: Wed,
                          hour_div_12: 0, hour_mod_12: 4, minute: 26, second: 40,
                          nanosecond: 12_345_678, timestamp: 1_419_967_600),
            ymdhmsn(2014, 12, 31, 4, 26, 40, 12_345_678)
        );

        // more timestamps
        let max_days_from_year_1970 =
            NaiveDate::MAX.signed_duration_since(NaiveDate::from_ymd(1970, 1, 1));
        let year_0_from_year_1970 =
            NaiveDate::from_ymd(0, 1, 1).signed_duration_since(NaiveDate::from_ymd(1970, 1, 1));
        let min_days_from_year_1970 =
            NaiveDate::MIN.signed_duration_since(NaiveDate::from_ymd(1970, 1, 1));
        assert_eq!(
            parse!(timestamp: min_days_from_year_1970.num_seconds()),
            ymdhms(NaiveDate::MIN.year(), 1, 1, 0, 0, 0)
        );
        assert_eq!(
            parse!(timestamp: year_0_from_year_1970.num_seconds()),
            ymdhms(0, 1, 1, 0, 0, 0)
        );
        assert_eq!(
            parse!(timestamp: max_days_from_year_1970.num_seconds() + 86399),
            ymdhms(NaiveDate::MAX.year(), 12, 31, 23, 59, 59)
        );

        // leap seconds #1: partial fields
        assert_eq!(parse!(second: 59, timestamp: 1_341_100_798), Err(IMPOSSIBLE));
        assert_eq!(parse!(second: 59, timestamp: 1_341_100_799), ymdhms(2012, 6, 30, 23, 59, 59));
        assert_eq!(parse!(second: 59, timestamp: 1_341_100_800), Err(IMPOSSIBLE));
        assert_eq!(
            parse!(second: 60, timestamp: 1_341_100_799),
            ymdhmsn(2012, 6, 30, 23, 59, 59, 1_000_000_000)
        );
        assert_eq!(
            parse!(second: 60, timestamp: 1_341_100_800),
            ymdhmsn(2012, 6, 30, 23, 59, 59, 1_000_000_000)
        );
        assert_eq!(parse!(second: 0, timestamp: 1_341_100_800), ymdhms(2012, 7, 1, 0, 0, 0));
        assert_eq!(parse!(second: 1, timestamp: 1_341_100_800), Err(IMPOSSIBLE));
        assert_eq!(parse!(second: 60, timestamp: 1_341_100_801), Err(IMPOSSIBLE));

        // leap seconds #2: full fields
        // we need to have separate tests for them since it uses another control flow.
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 59, timestamp: 1_341_100_798),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 59, timestamp: 1_341_100_799),
            ymdhms(2012, 6, 30, 23, 59, 59)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 59, timestamp: 1_341_100_800),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 60, timestamp: 1_341_100_799),
            ymdhmsn(2012, 6, 30, 23, 59, 59, 1_000_000_000)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 60, timestamp: 1_341_100_800),
            ymdhmsn(2012, 6, 30, 23, 59, 59, 1_000_000_000)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 183, hour_div_12: 0, hour_mod_12: 0,
                          minute: 0, second: 0, timestamp: 1_341_100_800),
            ymdhms(2012, 7, 1, 0, 0, 0)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 183, hour_div_12: 0, hour_mod_12: 0,
                          minute: 0, second: 1, timestamp: 1_341_100_800),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(year: 2012, ordinal: 182, hour_div_12: 1, hour_mod_12: 11,
                          minute: 59, second: 60, timestamp: 1_341_100_801),
            Err(IMPOSSIBLE)
        );

        // error codes
        assert_eq!(
            parse!(year: 2015, month: 1, day: 20, weekday: Tue,
                          hour_div_12: 2, hour_mod_12: 1, minute: 35, second: 20),
            Err(OUT_OF_RANGE)
        ); // `hour_div_12` is out of range
    }

    #[test]
    fn test_parsed_to_datetime() {
        macro_rules! parse {
            ($($k:ident: $v:expr),*) => (
                Parsed { $($k: Some($v),)* ..Parsed::new() }.to_datetime()
            )
        }

        let ymdhmsn = |y, m, d, h, n, s, nano, off| {
            Ok(FixedOffset::east(off).ymd(y, m, d).and_hms_nano(h, n, s, nano))
        };

        assert_eq!(parse!(offset: 0), Err(NOT_ENOUGH));
        assert_eq!(
            parse!(year: 2014, ordinal: 365, hour_div_12: 0, hour_mod_12: 4,
                          minute: 26, second: 40, nanosecond: 12_345_678),
            Err(NOT_ENOUGH)
        );
        assert_eq!(
            parse!(year: 2014, ordinal: 365, hour_div_12: 0, hour_mod_12: 4,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 0),
            ymdhmsn(2014, 12, 31, 4, 26, 40, 12_345_678, 0)
        );
        assert_eq!(
            parse!(year: 2014, ordinal: 365, hour_div_12: 1, hour_mod_12: 1,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 32400),
            ymdhmsn(2014, 12, 31, 13, 26, 40, 12_345_678, 32400)
        );
        assert_eq!(
            parse!(year: 2014, ordinal: 365, hour_div_12: 0, hour_mod_12: 1,
                          minute: 42, second: 4, nanosecond: 12_345_678, offset: -9876),
            ymdhmsn(2014, 12, 31, 1, 42, 4, 12_345_678, -9876)
        );
        assert_eq!(
            parse!(year: 2015, ordinal: 1, hour_div_12: 0, hour_mod_12: 4,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 86_400),
            Err(OUT_OF_RANGE)
        ); // `FixedOffset` does not support such huge offset
    }

    #[test]
    fn test_parsed_to_datetime_with_timezone() {
        macro_rules! parse {
            ($tz:expr; $($k:ident: $v:expr),*) => (
                Parsed { $($k: Some($v),)* ..Parsed::new() }.to_datetime_with_timezone(&$tz)
            )
        }

        // single result from ymdhms
        assert_eq!(
            parse!(Utc;
                          year: 2014, ordinal: 365, hour_div_12: 0, hour_mod_12: 4,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 0),
            Ok(Utc.ymd(2014, 12, 31).and_hms_nano(4, 26, 40, 12_345_678))
        );
        assert_eq!(
            parse!(Utc;
                          year: 2014, ordinal: 365, hour_div_12: 1, hour_mod_12: 1,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 32400),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(FixedOffset::east(32400);
                          year: 2014, ordinal: 365, hour_div_12: 0, hour_mod_12: 4,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 0),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(FixedOffset::east(32400);
                          year: 2014, ordinal: 365, hour_div_12: 1, hour_mod_12: 1,
                          minute: 26, second: 40, nanosecond: 12_345_678, offset: 32400),
            Ok(FixedOffset::east(32400).ymd(2014, 12, 31).and_hms_nano(13, 26, 40, 12_345_678))
        );

        // single result from timestamp
        assert_eq!(
            parse!(Utc; timestamp: 1_420_000_000, offset: 0),
            Ok(Utc.ymd(2014, 12, 31).and_hms(4, 26, 40))
        );
        assert_eq!(parse!(Utc; timestamp: 1_420_000_000, offset: 32400), Err(IMPOSSIBLE));
        assert_eq!(
            parse!(FixedOffset::east(32400); timestamp: 1_420_000_000, offset: 0),
            Err(IMPOSSIBLE)
        );
        assert_eq!(
            parse!(FixedOffset::east(32400); timestamp: 1_420_000_000, offset: 32400),
            Ok(FixedOffset::east(32400).ymd(2014, 12, 31).and_hms(13, 26, 40))
        );

        // TODO test with a variable time zone (for None and Ambiguous cases)
    }
}