cal: simplify calendar reformat calculations

The only September 1752 offset calculation that is necessary is whether
Sun or Mon is the first day of the week.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/misc-utils/cal.c b/misc-utils/cal.c
index 433db72df0ac044ffc6e3205e0751c96a6ad9e91..a89ca76489c36a6b70ba29a5267eee17f4f1085b 100644 (file)
--- a/misc-utils/cal.c
+++ b/misc-utils/cal.c
@@ -200,27 +200,16 @@ static int days_in_month[2][13] = {
        {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
 };
 
-#define SEP1752_OFS            4               /* sep1752[4] is a Sunday */
-
-/* 1 Sep 1752 is represented by sep1752[6] and j_sep1752[6] */
-int sep1752[MAXDAYS+6] = {
-                               SPACE,  SPACE,  SPACE,  SPACE,
+/* September 1752 is special, and has static assignments for both date
+ * and Julian representations.  */
+ int d_sep1752[MAXDAYS / 2] = {
        SPACE,  SPACE,  1,      2,      14,     15,     16,
        17,     18,     19,     20,     21,     22,     23,
-       24,     25,     26,     27,     28,     29,     30,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE
-}, j_sep1752[MAXDAYS+6] = {
-                               SPACE,  SPACE,  SPACE,  SPACE,
+       24,     25,     26,     27,     28,     29,     30
+}, j_sep1752[MAXDAYS / 2] = {
        SPACE,  SPACE,  245,    246,    258,    259,    260,
        261,    262,    263,    264,    265,    266,    267,
-       268,    269,    270,    271,    272,    273,    274,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
-       SPACE,  SPACE
+       268,    269,    270,    271,    272,    273,    274
 }, empty[MAXDAYS] = {
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
        SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,  SPACE,
@@ -670,18 +659,18 @@ yearly(int day, int year) {
 void
 day_array(int day, int month, int year, int *days) {
        int julday, daynum, dw, dm;
-       int *d_sep1752;
-
-       if (month == REFORMATION_MONTH && year == REFORMATION_YEAR) {
-               int sep1752_ofs = (weekstart + SEP1752_OFS) % 7;
-               d_sep1752 = julian ? j_sep1752 : sep1752;
-               memcpy(days, d_sep1752 + sep1752_ofs, MAXDAYS * sizeof(int));
-               for (dm=0; dm<MAXDAYS; dm++)
-                       if (j_sep1752[dm + sep1752_ofs] == day)
+       int *sep1752;
+
+       memcpy(days, empty, MAXDAYS * sizeof(int));
+       if (year == REFORMATION_YEAR && month == REFORMATION_MONTH) {
+               sep1752 = julian ? j_sep1752 : d_sep1752;
+               memcpy(days, sep1752 + weekstart,
+                      ((MAXDAYS / 2) - weekstart) * sizeof(int));
+               for (dm = 0; dm < MAXDAYS / 2; dm++)
+                       if (j_sep1752[dm] == day)
                                days[dm] |= TODAY_FLAG;
                return;
        }
-       memcpy(days, empty, MAXDAYS * sizeof(int));
        dm = days_in_month[leap_year(year)][month];
        dw = (day_in_week(1, month, year) - weekstart + DAYS_IN_WEEK) % DAYS_IN_WEEK;
        julday = day_in_year(1, month, year);