Fix recurrence rule expansion with ordered weekday

When the order of a weekday in BYDAY rule expansion (like -5SA or 5SU
for monthly or 55WE for yearly) exceeds the number of available weekdays
in the period (month or year), rule expansion with negative order could
result in a floating point exception. The reason: the modified frequency
might become zero.

Solution. Check order against number of available weekdays and terminate
expansion early whenever possible (also for positive orders).

Signed-off-by: Lars Henriksen <LarsHenriksen@get2net.dk>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>
This commit is contained in:
Lars Henriksen 2020-05-07 21:39:23 +02:00 committed by Lukas Fleischer
parent fabacecd16
commit bd238bfd7c
3 changed files with 58 additions and 21 deletions

View File

@ -1173,7 +1173,7 @@ static int expand_monthly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
LLIST_FOREACH(&rpt->bywday, i) {
w = LLIST_GET_DATA(i);
int order, wday;
int order, wday, nbwd;
localtime_r(&start, &tm_start);
/*
@ -1188,6 +1188,11 @@ static int expand_monthly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
*/
order = *w / WEEKINDAYS;
wday = *w % WEEKINDAYS;
nbwd = wday_per_month(tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday);
if (nbwd < order)
return 0;
r.freq = order;
tm_start.tm_mday = 1;
tm_start.tm_mon = tm_day.tm_mon;
@ -1218,11 +1223,12 @@ static int expand_monthly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
*/
order = -(*w) / WEEKINDAYS;
wday = -(*w) % WEEKINDAYS;
r.freq = wday_per_month(
tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday
) - order + 1;
nbwd = wday_per_month(tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday);
if (nbwd < order)
return 0;
r.freq = nbwd - order + 1;
tm_start.tm_mday = 1;
tm_start.tm_mon = tm_day.tm_mon;
tm_start.tm_year = tm_day.tm_year;
@ -1259,7 +1265,7 @@ static int expand_yearly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
{
struct tm tm_start, tm_day;
llist_item_t *i, *j;
int *m, *w, mday, wday, order;
int *m, *w, mday, wday, order, nbwd;
time_t nstart;
struct rpt r;
@ -1312,6 +1318,19 @@ static int expand_yearly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
*/
order = *w / WEEKINDAYS;
wday = *w % WEEKINDAYS;
if (rpt->bymonth.head)
nbwd = wday_per_month(
tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday
);
else
nbwd = wday_per_year(
tm_day.tm_year + 1900,
wday
);
if (nbwd < order)
return 0;
r.freq = order;
tm_start.tm_mday = 1;
if (rpt->bymonth.head)
@ -1344,21 +1363,25 @@ static int expand_yearly(time_t start, long dur, struct rpt *rpt, llist_t *exc,
*/
order = -(*w) / WEEKINDAYS;
wday = -(*w) % WEEKINDAYS;
if (rpt->bymonth.head) {
r.freq = wday_per_month(
tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday
) - order + 1;
tm_start.tm_mon = tm_day.tm_mon;
} else {
r.freq = wday_per_year(
tm_day.tm_year + 1900,
wday
) - order + 1;
tm_start.tm_mon = 0;
}
if (rpt->bymonth.head)
nbwd = wday_per_month(
tm_day.tm_mon + 1,
tm_day.tm_year + 1900,
wday
);
else
nbwd = wday_per_year(
tm_day.tm_year + 1900,
wday
);
if (nbwd < order)
return 0;
r.freq = nbwd - order + 1;
tm_start.tm_mday = 1;
if (rpt->bymonth.head)
tm_start.tm_mon = tm_day.tm_mon;
else
tm_start.tm_mon = 0;
tm_start.tm_year = tm_day.tm_year;
tm_start.tm_isdst = -1;
nstart = date_sec_change(

View File

@ -25,3 +25,4 @@
12/25/1997 [1] {3Y w-11} Last Thursday of the year every third year, forever (FREQ=YEARLY;INTERVAL=3;BYDAY=-1TH)
06/22/1997 [1] {2Y w0 w1} Every Sunday and Monday, every other year (FREQ=YEARLY;INTERVAL=2;BYDAY=SU,MO)
02/01/1997 [1] {1Y -> 01/31/2005 d1 d29 m2} Every year on February 1 and 29 for eight years (RRULE:FREQ=YEARLY;UNTIL=20050131T000000Z;BYMONTH=2;BYMONTHDAY=1,29)
08/01/2020 @ 08:41 -> 08/01/2020 @ 10:11 {1M w-41} |negative ordered weekday may not exist

View File

@ -6,6 +6,13 @@
if [ "$1" = 'actual' ]; then
"$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
-Q --from 1/1/1996 --to 12/31/2007 --filter-type recur
echo ""
echo "Floating point exception?"
"$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
-Q --day 8/1/2020 --filter-type recur &&
"$CALCURSE" --read-only -D "$DATA_DIR"/ -c "$DATA_DIR/rfc5545" \
-Q --day 11/1/2020 --filter-type recur &&
echo "No Floating point exception on November 1, 2020"
elif [ "$1" = 'expected' ]; then
cat <<EOD
11/05/96:
@ -5323,6 +5330,12 @@ elif [ "$1" = 'expected' ]; then
12/31/07:
* Every Sunday and Monday, every other year (FREQ=YEARLY;INTERVAL=2;BYDAY=SU,MO)
Floating point exception?
08/01/20:
- 08:41 -> 10:11
negative ordered weekday may not exist
No Floating point exception on November 1, 2020
EOD
else
./run-test "$0"