WL#1175: more default_week_formats for iso compatibility

New formats added for 'week()' function and 'default_week_format' option(4 - 7).
Next formats is supported now:
*Value* *Meaning*
  `0'     Week starts on Sunday; First Sunday of the year starts week 1.
  	  Week() returns 0-53.
  `1'     Week starts on Monday; Weeks numbered according to ISO 8601:1988.
	  Week() returns 0-53.
  `2'     Week starts on Sunday; First Sunday of the year starts week 1.
  	  Week() returns 1-53.
  `3'     Week starts on Monday; Weeks numbered according to ISO 8601:1988.
	  Week() returns 1-53.
  `4'     Week starts on Sunday; Weeks numbered according to ISO 8601:1988.
	  Week() returns 0-53.
  `5'     Week starts on Monday;  First Monday of the year starts week 1.
  	  Week() returns 0-53.
  `6'     Week starts on Sunday; Weeks numbered according to ISO 8601:1988.
	  Week() returns 1-53.
  `7'     Week starts on Monday;  First Monday of the year starts week 1.
  	  Week() returns 1-53.


mysql-test/r/func_time.result:
  Test for 'default_week_format' option and 'week' function
mysql-test/t/func_time.test:
  Test for 'default_week_format' option and 'week' function
sql/item_timefunc.cc:
  WL#1175 more default_week_formats for iso compatibility
sql/mysql_priv.h:
  WL#1175 more default_week_formats for iso compatibility
sql/mysqld.cc:
  WL#1175 more default_week_formats for iso compatibility
sql/time.cc:
  WL#1175 more default_week_formats for iso compatibility

1 files changed, 49 insertions, 19 deletions

diff --git a/sql/time.cc b/sql/time.cc
index 321a8ba16e5..bf218fa58ab 100644
--- a/sql/time.cc
+++ b/sql/time.cc
@@ -175,42 +175,72 @@ uint calc_days_in_year(uint year)
     366 : 365;
 }
 
-/* Calculate week.  If 'with_year' is not set, then return a week 0-53, where
-   0 means that it's the last week of the previous year.
-   If 'with_year' is set then the week will always be in the range 1-53 and
-   the year out parameter will contain the year for the week */
 
-uint calc_week(TIME *l_time, bool with_year, bool sunday_first_day_of_week,
-	       uint *year)
+/*
+  The bits in week_format has the following meaning:
+   WEEK_MONDAY_FIRST (0)  If not set	Sunday is first day of week
+      		   	  If set	Monday is first day of week
+   WEEK_YEAR (1)	  If not set	Week is in range 0-53
+
+   	Week 0 is returned for the the last week of the previous year (for
+	a date at start of january) In this case one can get 53 for the
+	first week of next year.  This flag ensures that the week is
+	relevant for the given year. Note that this flag is only
+	releveant if WEEK_JANUARY is not set.
+
+			  If set	 Week is in range 1-53.
+
+	In this case one may get week 53 for a date in January (when
+	the week is that last week of previous year) and week 1 for a
+	date in December.
+
+  WEEK_FIRST_WEEKDAY (2)  If not set	Weeks are numbered according
+			   		to ISO 8601:1988
+			  If set	The week that contains the first
+					'first-day-of-week' is week 1.
+	
+	ISO 8601:1988 means that if the week containing January 1 has
+	four or more days in the new year, then it is week 1;
+	Otherwise it is the last week of the previous year, and the
+	next week is week 1.
+*/
+
+uint calc_week(TIME *l_time, uint week_behaviour, uint *year)
 {
   uint days;
   ulong daynr=calc_daynr(l_time->year,l_time->month,l_time->day);
   ulong first_daynr=calc_daynr(l_time->year,1,1);
-  uint weekday=calc_weekday(first_daynr,sunday_first_day_of_week);
+  bool monday_first= test(week_behaviour & WEEK_MONDAY_FIRST);
+  bool week_year= test(week_behaviour & WEEK_YEAR);
+  bool first_weekday= test(week_behaviour & WEEK_FIRST_WEEKDAY);
+
+  uint weekday=calc_weekday(first_daynr, !monday_first);
   *year=l_time->year;
-  if (l_time->month == 1 && l_time->day <= 7-weekday &&
-      ((!sunday_first_day_of_week && weekday >= 4) ||
-       (sunday_first_day_of_week && weekday != 0)))
+
+  if (l_time->month == 1 && l_time->day <= 7-weekday)
   {
-    /* Last week of the previous year */
-    if (!with_year)
+    if (!week_year && 
+	(first_weekday && weekday != 0 ||
+	 !first_weekday && weekday >= 4))
       return 0;
-    with_year=0;				// Don't check the week again
+    week_year= 1;
     (*year)--;
     first_daynr-= (days=calc_days_in_year(*year));
     weekday= (weekday + 53*7- days) % 7;
   }
-  if ((sunday_first_day_of_week && weekday != 0) ||
-      (!sunday_first_day_of_week && weekday >= 4))
+
+  if ((first_weekday && weekday != 0) ||
+      (!first_weekday && weekday >= 4))
     days= daynr - (first_daynr+ (7-weekday));
   else
     days= daynr - (first_daynr - weekday);
-  if (with_year && days >= 52*7)
+
+  if (week_year && days >= 52*7)
   {
-    /* Check if we are on the first week of the next year (or week 53) */
     weekday= (weekday + calc_days_in_year(*year)) % 7;
-    if (weekday < 4)
-    {					// We are at first week on next year
+    if (!first_weekday && weekday < 4 ||
+	first_weekday && weekday == 0)
+    {
       (*year)++;
       return 1;
     }