deep_time/
leap_seconds.rs

1//! Leap seconds table from the official IANA leap-seconds.list
2//![](https://data.iana.org/time-zones/data/leap-seconds.list)
3//! Updated through IERS Bulletin C as of April 2026.
4//! Last leap second: 2017-01-01 (TAI-UTC = 37 s)
5//! File expires: 28 December 2026
6
7use crate::Dt;
8
9pub struct LeapSecond {
10    pub ntp_timestamp: i64,
11    pub leap_seconds_after: i64,
12    pub utc_sec: i64,
13    pub tai_sec: i64,
14}
15
16pub const LEAP_SECS: &[LeapSecond] = &[
17    LeapSecond {
18        ntp_timestamp: 2272060800,
19        leap_seconds_after: 10,
20        utc_sec: -883656000,
21        tai_sec: -883655991, // was -883655990
22    }, // 1 Jan 1972 (start of modern UTC definition)
23    LeapSecond {
24        ntp_timestamp: 2287785600,
25        leap_seconds_after: 11,
26        utc_sec: -867931200,
27        tai_sec: -867931190, // was -867931189
28    }, // 1 Jul 1972
29    LeapSecond {
30        ntp_timestamp: 2303683200,
31        leap_seconds_after: 12,
32        utc_sec: -852033600,
33        tai_sec: -852033589, // was -852033588
34    }, // 1 Jan 1973
35    LeapSecond {
36        ntp_timestamp: 2335219200,
37        leap_seconds_after: 13,
38        utc_sec: -820497600,
39        tai_sec: -820497588, // was -820497587
40    }, // 1 Jan 1974
41    LeapSecond {
42        ntp_timestamp: 2366755200,
43        leap_seconds_after: 14,
44        utc_sec: -788961600,
45        tai_sec: -788961587, // was -788961586
46    }, // 1 Jan 1975
47    LeapSecond {
48        ntp_timestamp: 2398291200,
49        leap_seconds_after: 15,
50        utc_sec: -757425600,
51        tai_sec: -757425586, // was -757425585
52    }, // 1 Jan 1976
53    LeapSecond {
54        ntp_timestamp: 2429913600,
55        leap_seconds_after: 16,
56        utc_sec: -725803200,
57        tai_sec: -725803185, // was -725803184
58    }, // 1 Jan 1977
59    LeapSecond {
60        ntp_timestamp: 2461449600,
61        leap_seconds_after: 17,
62        utc_sec: -694267200,
63        tai_sec: -694267184, // was -694267183
64    }, // 1 Jan 1978
65    LeapSecond {
66        ntp_timestamp: 2492985600,
67        leap_seconds_after: 18,
68        utc_sec: -662731200,
69        tai_sec: -662731183, // was -662731182
70    }, // 1 Jan 1979
71    LeapSecond {
72        ntp_timestamp: 2524521600,
73        leap_seconds_after: 19,
74        utc_sec: -631195200,
75        tai_sec: -631195182, // was -631195181
76    }, // 1 Jan 1980
77    LeapSecond {
78        ntp_timestamp: 2571782400,
79        leap_seconds_after: 20,
80        utc_sec: -583934400,
81        tai_sec: -583934381, // was -583934380
82    }, // 1 Jul 1981
83    LeapSecond {
84        ntp_timestamp: 2603318400,
85        leap_seconds_after: 21,
86        utc_sec: -552398400,
87        tai_sec: -552398380, // was -552398379
88    }, // 1 Jul 1982
89    LeapSecond {
90        ntp_timestamp: 2634854400,
91        leap_seconds_after: 22,
92        utc_sec: -520862400,
93        tai_sec: -520862379, // was -520862378
94    }, // 1 Jul 1983
95    LeapSecond {
96        ntp_timestamp: 2698012800,
97        leap_seconds_after: 23,
98        utc_sec: -457704000,
99        tai_sec: -457703978, // was -457703977
100    }, // 1 Jul 1985
101    LeapSecond {
102        ntp_timestamp: 2776982400,
103        leap_seconds_after: 24,
104        utc_sec: -378734400,
105        tai_sec: -378734377, // was -378734376
106    }, // 1 Jan 1988
107    LeapSecond {
108        ntp_timestamp: 2840140800,
109        leap_seconds_after: 25,
110        utc_sec: -315576000,
111        tai_sec: -315575976, // was -315575975
112    }, // 1 Jan 1990
113    LeapSecond {
114        ntp_timestamp: 2871676800,
115        leap_seconds_after: 26,
116        utc_sec: -284040000,
117        tai_sec: -284039975, // was -284039974
118    }, // 1 Jan 1991
119    LeapSecond {
120        ntp_timestamp: 2918937600,
121        leap_seconds_after: 27,
122        utc_sec: -236779200,
123        tai_sec: -236779174, // was -236779173
124    }, // 1 Jul 1992
125    LeapSecond {
126        ntp_timestamp: 2950473600,
127        leap_seconds_after: 28,
128        utc_sec: -205243200,
129        tai_sec: -205243173, // was -205243172
130    }, // 1 Jul 1993
131    LeapSecond {
132        ntp_timestamp: 2982009600,
133        leap_seconds_after: 29,
134        utc_sec: -173707200,
135        tai_sec: -173707172, // was -173707171
136    }, // 1 Jul 1994
137    LeapSecond {
138        ntp_timestamp: 3029443200,
139        leap_seconds_after: 30,
140        utc_sec: -126273600,
141        tai_sec: -126273571, // was -126273570
142    }, // 1 Jan 1996
143    LeapSecond {
144        ntp_timestamp: 3076704000,
145        leap_seconds_after: 31,
146        utc_sec: -79012800,
147        tai_sec: -79012770, // was -79012769
148    }, // 1 Jul 1997
149    LeapSecond {
150        ntp_timestamp: 3124137600,
151        leap_seconds_after: 32,
152        utc_sec: -31579200,
153        tai_sec: -31579169, // was -31579168
154    }, // 1 Jan 1999
155    LeapSecond {
156        ntp_timestamp: 3345062400,
157        leap_seconds_after: 33,
158        utc_sec: 189345600,
159        tai_sec: 189345632, // was 189345633
160    }, // 1 Jan 2006
161    LeapSecond {
162        ntp_timestamp: 3439756800,
163        leap_seconds_after: 34,
164        utc_sec: 284040000,
165        tai_sec: 284040033, // was 284040034
166    }, // 1 Jan 2009
167    LeapSecond {
168        ntp_timestamp: 3550089600,
169        leap_seconds_after: 35,
170        utc_sec: 394372800,
171        tai_sec: 394372834, // was 394372835
172    }, // 1 Jul 2012
173    LeapSecond {
174        ntp_timestamp: 3644697600,
175        leap_seconds_after: 36,
176        utc_sec: 488980800,
177        tai_sec: 488980835, // was 488980836
178    }, // 1 Jul 2015
179    LeapSecond {
180        ntp_timestamp: 3692217600,
181        leap_seconds_after: 37,
182        utc_sec: 536500800,
183        tai_sec: 536500836, // was 536500837
184    }, // 1 Jan 2017
185];
186
187#[derive(Copy, Clone, Debug)]
188pub struct LeapInfo {
189    pub offset: i64,
190    pub leaps_inserted: i64,
191    pub is_leap_second: bool,
192}
193
194pub const fn get_leap_seconds(tp: &Dt, from_civil: bool) -> LeapInfo {
195    let mut offset = 0i64;
196    let mut leaps_inserted = 0i64;
197    let mut i = 0usize;
198
199    while i < LEAP_SECS.len() {
200        let entry = &LEAP_SECS[i];
201
202        let entry_sec = if from_civil {
203            entry.utc_sec
204        } else {
205            entry.tai_sec
206        };
207
208        if tp.sec() == entry_sec {
209            return LeapInfo {
210                offset: entry.leap_seconds_after,
211                leaps_inserted: i as i64 + 1,
212                is_leap_second: true,
213            };
214        }
215
216        if tp.sec() < entry_sec {
217            break;
218        }
219
220        offset = entry.leap_seconds_after;
221        leaps_inserted = i as i64 + 1;
222        i += 1;
223    }
224
225    LeapInfo {
226        offset,
227        leaps_inserted,
228        is_leap_second: false,
229    }
230}
deep_time/leap_seconds.rs

deep_time/
leap_seconds.rs
