[PATCH 3/7] Add helper to jump to specified number of months

[Nikolay Sivov]

---
 dlls/comctl32/monthcal.c |   30 ++++++++++++------------------
 1 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/dlls/comctl32/monthcal.c b/dlls/comctl32/monthcal.c
index 5f5c7c2..91cd4cb 100644
--- a/dlls/comctl32/monthcal.c
+++ b/dlls/comctl32/monthcal.c
@@ -455,36 +455,30 @@ int MONTHCAL_CalculateDayOfWeek(SYSTEMTIME *date, BOOL inplace)
   return st.wDayOfWeek;
 }
 
-/* properly updates date to point on next month */
-static inline void MONTHCAL_GetNextMonth(SYSTEMTIME *date)
+/* add/substract 'months' from date */
+static inline void MONTHCAL_GetMonth(SYSTEMTIME *date, INT months)
 {
   INT length;
 
-  if(++date->wMonth > 12)
-  {
-    date->wMonth = 1;
-    date->wYear++;
-  }
+  date->wMonth += months;
+  date->wYear  += date->wMonth > 0 ? (date->wMonth - 1) / 12 : date->wMonth / 12 - 1;
+  date->wMonth  = date->wMonth > 0 ? (date->wMonth - 1) % 12 + 1 : 12 + date->wMonth % 12;
   /* fix moving from last day in a month */
   length = MONTHCAL_MonthLength(date->wMonth, date->wYear);
   if(date->wDay > length) date->wDay = length;
   MONTHCAL_CalculateDayOfWeek(date, TRUE);
 }
 
+/* properly updates date to point on next month */
+static inline void MONTHCAL_GetNextMonth(SYSTEMTIME *date)
+{
+  return MONTHCAL_GetMonth(date, 1);
+}
+
 /* properly updates date to point on prev month */
 static inline void MONTHCAL_GetPrevMonth(SYSTEMTIME *date)
 {
-  INT length;
-
-  if(--date->wMonth < 1)
-  {
-    date->wMonth = 12;
-    date->wYear--;
-  }
-  /* fix moving from last day in a month */
-  length = MONTHCAL_MonthLength(date->wMonth, date->wYear);
-  if(date->wDay > length) date->wDay = length;
-  MONTHCAL_CalculateDayOfWeek(date, TRUE);
+  return MONTHCAL_GetMonth(date, -1);
 }
 
 /* Returns full date for a first currently visible day */
-- 
1.5.6.5



--------------020900010308010708040102--