commit 7bc7e8f3bdc9afe901af85229129943a24293ab4
parent 23b6e86f28aac4313105ca53136f8ab6b2646986
Author: Byron Torres <b@torresjrjr.com>
Date: Sun, 16 Jan 2022 13:41:14 +0000
add temporary leap seconds data
Signed-off-by: Byron Torres <b@torresjrjr.com>
Diffstat:
1 file changed, 62 insertions(+), 0 deletions(-)
diff --git a/time/chrono/leapsec.ha b/time/chrono/leapsec.ha
@@ -1 +1,63 @@
use time;
+
+// UTC timestamps and their TAI offsets, sourced from leap-seconds.list
+// updated: 8 July 2016
+// expires: 28 June 2022
+//
+// TODO:
+// this is a temporary hard-coded list. read leap-second data from a source.
+//
+// Separating concerns of timezones and timescale has proven troublesome, since
+// data of timezone transitions and leap seconds are both encoded in the TZif
+// files generated from the Olson/tz project, and typically installed at
+// /usr/share/zoneinfo. Thus, for typical programs in a minimal system like
+// Alpine, the entire system can only be configured to run either with or
+// without adherence to leap second information.
+//
+// Olson himself has expressed for the support of Martian time, which with our
+// approach, may depend on multi-timescale support:
+//
+// > The tz database does not currently support Mars time, but it is documented
+// > here in the hopes that support will be added eventually. 8
+//
+// Some systems have an ideal /usr/share/zoneinfo/leap-seconds.list file, which
+// is directly downloaded from a periodically maintained file at
+// <ftp://ftp.nist.gov/pub/time/leap-seconds.list> or
+// <ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list>. This file contains a
+// list of Unix timestamps (2272060800) and absolute timescale offsets (+10). A
+// good solution ought to use this.
+//
+// Some systems have a less ideal /usr/share/zoneinfo/leapseconds file, which is
+// generated from leap-seconds.list using an awk script, and contains Gregorian
+// datetime timestamps (1972 Jun 30 23:59:60) and relative timescale corrections
+// (+S, -S). This may be a fallback solution.
+const leaps_utc: [](i64, i64) = [
+ (2272060800, 10),
+ (2287785600, 11),
+ (2303683200, 12),
+ (2335219200, 13),
+ (2366755200, 14),
+ (2398291200, 15),
+ (2429913600, 16),
+ (2461449600, 17),
+ (2492985600, 18),
+ (2524521600, 19),
+ (2571782400, 20),
+ (2603318400, 21),
+ (2634854400, 22),
+ (2698012800, 23),
+ (2776982400, 24),
+ (2840140800, 25),
+ (2871676800, 26),
+ (2918937600, 27),
+ (2950473600, 28),
+ (2982009600, 29),
+ (3029443200, 30),
+ (3076704000, 31),
+ (3124137600, 32),
+ (3345062400, 33),
+ (3439756800, 34),
+ (3550089600, 35),
+ (3644697600, 36),
+ (3692217600, 37),
+];
