icalrecur.c: fixed handling of BYWEEKNO=1 with BYDAY (added tests for first and last weeks)

3 files changed, 51 insertions, 8 deletions

diff --git a/src/libical/icalrecur.c b/src/libical/icalrecur.c
index 1437198f..c1f960e6 100644
--- a/src/libical/icalrecur.c
+++ b/src/libical/icalrecur.c
@@ -2329,8 +2329,11 @@ static int expand_by_day(icalrecur_iterator *impl, int year,
             }
         }
 
-        (void)__icaltime_from_day_of_year(impl, day + doy_offset, year,
-                                          &this_weekno);
+        if (doy_offset < 0) this_weekno = 1;
+        else {
+            (void)__icaltime_from_day_of_year(impl, day + doy_offset, year,
+                                              &this_weekno);
+        }
 
         /* Add instance(s) of the weekday within the period */
         do {
@@ -2671,15 +2674,37 @@ static int expand_year_days(icalrecur_iterator *impl, int year)
             }
         } else {
             /* Numeric BYDAY are within the year */
+            short doy_offset = 0, last_day;
+
+            if (has_by_data(impl, BY_WEEK_NO)) {
+                int weekno;
+
+                /* See which week contains Jan 1 */
+                (void)__icaltime_from_day_of_year(impl, 1, year, &weekno);
+                if (weekno > 1) {
+                    /* Jan 1 is in last week of previous year - jump ahead */
+                    doy_offset += 7;
+                }
 
-            /* Get day of week of first day of year */
-            (void)get_day_of_year(impl, year, 1, 1, &first_dow);
+                /* Set start and end of ISO week-numbering year */
+                doy_offset += get_start_of_week(impl) - 1;
+                last_day = (7 * weeks_in_year(year));
 
-            /* Get day of week of last day of year */
-            set_day_of_year(impl, days_in_year);
-            last_dow = get_day_of_week(impl);
+                first_dow = impl->rule.week_start;
+                last_dow = (first_dow + 6) % 7;
+            }
+            else {
+                /* Get day of week of first day of year */
+                (void)get_day_of_year(impl, year, 1, 1, &first_dow);
+
+                /* Get day of week of last day of year */
+                set_day_of_year(impl, days_in_year);
+                last_dow = get_day_of_week(impl);
+
+                last_day = days_in_year;
+            }
 
-            set_pos_total += expand_by_day(impl, year, 0, days_in_year,
+            set_pos_total += expand_by_day(impl, year, doy_offset, last_day,
                                            first_dow, last_dow, limiting);
         }
     }
diff --git a/src/test/icalrecur_test.c b/src/test/icalrecur_test.c
index 7043cb3d..06c4078a 100644
--- a/src/test/icalrecur_test.c
+++ b/src/test/icalrecur_test.c
@@ -390,6 +390,16 @@ const struct recur rfc5545[] = {
      "FREQ=WEEKLY;BYDAY=WE,FR;INTERVAL=2;COUNT=4",
      NULL},
 
+    /* First 2 and last 2 ISO weeks of the year on Tue */
+    {"20130101T000000",
+     "FREQ=YEARLY;BYWEEKNO=1,2,-1,-2;BYDAY=TU;UNTIL=20170101T000000Z",
+     NULL},
+
+    /* 53rd ISO week of the year on Tue and Sat */
+    {"20130101T000000",
+     "FREQ=YEARLY;BYWEEKNO=53;BYDAY=TU,SA;UNTIL=20170101T000000Z",
+     NULL},
+
     {NULL, NULL, NULL}
 };
 
diff --git a/src/test/icalrecur_test.out b/src/test/icalrecur_test.out
index c08a19eb..4e3d03bc 100644
--- a/src/test/icalrecur_test.out
+++ b/src/test/icalrecur_test.out
@@ -272,3 +272,11 @@ INSTANCES:20130512T000000,20260512T000000,20390512T000000
 RRULE:FREQ=WEEKLY;BYDAY=WE,FR;INTERVAL=2;COUNT=4
 DTSTART:20190101T100000
 INSTANCES:20190102T100000,20190104T100000,20190116T100000,20190118T100000
+
+RRULE:FREQ=YEARLY;BYWEEKNO=1,2,-1,-2;BYDAY=TU;UNTIL=20170101T000000Z
+DTSTART:20130101T000000
+INSTANCES:20130101T000000,20130108T000000,20131217T000000,20131224T000000,20131231T000000,20140107T000000,20141216T000000,20141223T000000,20141230T000000,20150106T000000,20151222T000000,20151229T000000,20160105T000000,20160112T000000,20161220T000000,20161227T000000
+
+RRULE:FREQ=YEARLY;BYWEEKNO=53;BYDAY=TU,SA;UNTIL=20170101T000000Z
+DTSTART:20130101T000000
+INSTANCES:20151229T000000,20160102T000000