commit 7434a99d9688f5069aec10a6a1a3667ed07c1037
parent dd9d2af79b98311bf3e25e68dcc18dc1097d424b
Author: Byron Torres <b@torresjrjr.com>
Date: Wed, 11 Oct 2023 22:47:15 +0100
time::chrono: complete utc timescale conversion
Also tidy, drop static.
Fixes: https://todo.sr.ht/~sircmpwn/hare/642
Signed-off-by: Byron Torres <b@torresjrjr.com>
Diffstat:
1 file changed, 144 insertions(+), 83 deletions(-)
diff --git a/time/chrono/timescale.ha b/time/chrono/timescale.ha
@@ -86,23 +86,16 @@ export const tai: timescale = timescale {
};
fn tai_conv(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &tai =>
- buf[0] = i;
- return buf;
+ append(ret, i);
+ return ret;
case =>
return void;
};
};
-// TODO: Write proper conversion functions for all timescales.
-//
-// Ticket: https://todo.sr.ht/~sircmpwn/hare/642
-//
-// For UTC, conversion functions are to return two or no instants, depending on
-// any leap second events, and use a proper leap second table. See leapsec.ha.
-
// Coordinated Universal Time
//
@@ -122,10 +115,11 @@ export const utc: timescale = timescale {
};
fn utc_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &utc =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
if (!utc_isinitialized) {
match (init_utc_leapsecs()) {
@@ -136,28 +130,81 @@ fn utc_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
};
};
- const idx = lookup_leaps(&utc_leapsecs, time::unix(i));
- const ofst = utc_leapsecs[idx].1;
-
- if (time::unix(i) == utc_leapsecs[idx].0) {
- void;
+ const firstleap = utc_leapsecs[0]; // TODO: no leapsecs loaded
+ if (time::compare(i, time::from_unix(firstleap.0)) < 0) {
+ append(ret, time::instant {
+ sec = i.sec + firstleap.1,
+ nsec = i.nsec,
+ });
+ return ret;
};
- buf[0] = time::instant {
- sec = i.sec + 37,
- nsec = i.nsec,
+ for (let idx = len(utc_leapsecs) - 1; idx >= 0 ; idx -= 1) {
+ const leap = utc_leapsecs[idx];
+ const leapsecond = time::from_unix(leap.0);
+ const leapoffset = leap.1;
+ const diff = time::diff(leapsecond, i);
+
+ const prevleapoffset =
+ if (idx == 0) 0i64 else utc_leapsecs[idx - 1].1;
+ const offsetdiff =
+ (leapoffset - prevleapoffset) * time::SECOND;
+
+ // case of positive leap second (UTC repeats a second)
+ if (offsetdiff >= 0) {
+ if (diff >= 0) {
+ append(ret, time::instant {
+ sec = i.sec + leapoffset,
+ nsec = i.nsec,
+ });
+ return ret;
+ };
+
+ if (diff >= -offsetdiff && diff < 0) {
+ append(ret, [
+ time::instant {
+ sec = i.sec + prevleapoffset,
+ nsec = i.nsec,
+ },
+ time::instant {
+ sec = i.sec + leapoffset,
+ nsec = i.nsec,
+ },
+ ]...);
+ return ret;
+ };
+
+ continue;
+ };
+
+ // case of negative leap second (UTC skips a second)
+ if (offsetdiff < 0) {
+ if (diff >= 0) {
+ append(ret, time::instant {
+ sec = i.sec + leapoffset,
+ nsec = i.nsec,
+ });
+ return ret;
+ };
+
+ if (diff >= offsetdiff && diff < 0) {
+ return ret;
+ };
+
+ continue;
+ };
};
case =>
return void;
};
- return buf;
};
fn utc_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &utc =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
if (!utc_isinitialized) {
match (init_utc_leapsecs()) {
@@ -168,44 +215,55 @@ fn utc_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
};
};
- const idx = lookup_leaps(&utc_leapsecs, time::unix(i));
- const ofst = utc_leapsecs[idx].1;
-
- if (time::unix(i) == utc_leapsecs[idx].0) {
- void;
+ const firstleap = utc_leapsecs[0]; // TODO: no leapsecs loaded
+ if (time::compare(i, time::from_unix(firstleap.0 + firstleap.1)) < 0) {
+ append(ret, time::instant {
+ sec = i.sec - firstleap.1,
+ nsec = i.nsec,
+ });
+ return ret;
};
- buf[0] = time::instant {
- sec = i.sec - 37,
- nsec = i.nsec,
+ for (let idx = len(utc_leapsecs) - 1; idx >= 0 ; idx -= 1) {
+ const leap = utc_leapsecs[idx];
+ const leapsecond = time::from_unix(leap.0 + leap.1);
+ const leapoffset = leap.1;
+ const diff = time::diff(leapsecond, i);
+
+ const prevleapoffset =
+ if (idx == 0) 10i64 else utc_leapsecs[idx - 1].1;
+ const offsetdiff
+ = (leapoffset - prevleapoffset) * time::SECOND;
+
+ // case of positive leap second (UTC repeats a second)
+ if (offsetdiff >= 0) {
+ if (diff >= -offsetdiff) {
+ append(ret, time::instant {
+ sec = i.sec - leapoffset,
+ nsec = i.nsec,
+ });
+ return ret;
+ };
+
+ continue;
+ };
+
+ // case of negative leap second (UTC skips a second)
+ if (offsetdiff < 0) {
+ if (diff >= 0) {
+ append(ret, time::instant {
+ sec = i.sec - leapoffset,
+ nsec = i.nsec,
+ });
+ return ret;
+ };
+
+ continue;
+ };
};
case =>
return void;
};
- return buf;
-};
-
-fn lookup_leaps(list: *[](i64, i64), t: i64) size = {
- let lo = 0z, hi = len(list);
- for (hi - lo > 1) {
- const mid = lo + (hi - lo) / 2;
- const middle = list[mid].0;
- const cmp = time::compare(
- time::from_unix(t),
- time::from_unix(middle),
- );
- switch (cmp) {
- case -1 =>
- hi = mid;
- case 0 =>
- lo = mid; break;
- case 1 =>
- lo = mid;
- case =>
- abort("Unreachable");
- };
- };
- return lo;
};
@@ -226,29 +284,31 @@ export const gps: timescale = timescale {
def GPS_OFFSET: time::duration = -19 * time::SECOND;
fn gps_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &gps =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
- buf[0] = time::add(i, -GPS_OFFSET);
+ append(ret, time::add(i, -GPS_OFFSET));
+ return ret;
case =>
return void;
};
- return buf;
};
fn gps_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &gps =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
- buf[0] = time::add(i, GPS_OFFSET);
+ append(ret, time::add(i, GPS_OFFSET));
+ return ret;
case =>
return void;
};
- return buf;
};
@@ -269,30 +329,32 @@ export const tt: timescale = timescale {
def TT_OFFSET: time::duration = 32184 * time::MILLISECOND; // 32.184 seconds
fn tt_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &tt =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
- buf[0] = time::add(i, -TT_OFFSET);
+ append(ret, time::add(i, -TT_OFFSET));
+ return ret;
case =>
return void;
};
- return buf;
};
fn tt_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &tt =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
- buf[0] = time::add(i, TT_OFFSET);
+ append(ret, time::add(i, TT_OFFSET));
+ return ret;
case =>
return void;
};
- return buf;
};
// Arthur David Olson had expressed support for Martian time in his timezone
@@ -330,11 +392,11 @@ def DELTA_MARSEPOCH_JANSIX: time::duration = 44796 * 24 * time::HOUR;
def DELTA_JANSIX_ADJUSTMENT: time::duration = 82944 * time::MILLISECOND;
fn mtc_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &mtc =>
- buf[0] = i;
- return buf;
+ append(ret, i);
+ return ret;
case &tai =>
// Change epoch from that of the Mars Sol Date
// to the Earth-Mars convergence date 2000 Jan 6th.
@@ -352,20 +414,19 @@ fn mtc_convto(ts: *timescale, i: time::instant) ([]time::instant | void) = {
// Get the TAI time.
// assertion since TT and TAI are continuous.
- const ts = tt.convto(&tai, i) as []time::instant;
-
- return ts;
+ append(ret, (tt.convto(&tai, i) as []time::instant)[0]);
+ return ret;
case =>
- void;
+ return void;
};
-
};
fn mtc_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
- static let buf = [time::instant { ... }];
+ let ret: []time::instant = [];
switch (ts) {
case &mtc =>
- buf[0] = i;
+ append(ret, i);
+ return ret;
case &tai =>
// Get the "Terrestrial Time".
// assertion since TT and TAI are continuous.
@@ -383,9 +444,9 @@ fn mtc_convfrom(ts: *timescale, i: time::instant) ([]time::instant | void) = {
i = time::add(i, -DELTA_JANSIX_ADJUSTMENT);
// Change epoch to that of the Mars Sol Date.
- buf[0] = time::add(i, DELTA_MARSEPOCH_JANSIX);
+ append(ret, time::add(i, DELTA_MARSEPOCH_JANSIX));
+ return ret;
case =>
return void;
};
- return buf;
};
