From bd238bfd7c443fd974f5b7edd6c1abc0349bfa78 Mon Sep 17 00:00:00 2001
From: Lars Henriksen <LarsHenriksen@get2net.dk>
Date: Thu, 7 May 2020 21:39:23 +0200
Subject: 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>
---
src/recur.c | 63 +++++++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 43 insertions(+), 20 deletions(-)
(limited to 'src')
diff --git a/src/recur.c b/src/recur.c
index 997fb15..647ba11 100644
--- a/src/recur.c
+++ b/src/recur.c
@@ -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;
+ 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 {
- r.freq = wday_per_year(
- tm_day.tm_year + 1900,
- wday
- ) - order + 1;
+ else
tm_start.tm_mon = 0;
- }
- tm_start.tm_mday = 1;
tm_start.tm_year = tm_day.tm_year;
tm_start.tm_isdst = -1;
nstart = date_sec_change(
--
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