Localtime: compute year, month and day of the month.

1 files changed, 26 insertions, 0 deletions

diff --git a/src/localtime.c b/src/localtime.c
index a92d7464c..d4090e63c 100644
--- a/src/localtime.c
+++ b/src/localtime.c
@@ -69,4 +69,30 @@ void nolocks_localtime(struct tm *tmp, time_t t, time_t tz, int dst) {
      * where sunday = 0, so to calculate the day of the week we have to add 4
      * and take the modulo by 7. */
     tmp->tm_wday = (days+4)%7;
+
+    /* Calculate the current year. */
+    tmp->tm_year = 1970;
+    while(1) {
+        /* Leap years have one year more. */
+        time_t days_this_year = 365 + is_leap_year(tmp->tm_year);
+        if (days_this_year > days) break;
+        days -= days_this_year;
+        tmp->tm_year++;
+    }
+    tmp->tm_yday = days;  /* Number of day of the current year. */
+
+    /* We need to calculate in which month and day of the month we are. To do
+     * so we need to skip days according to how many days there are in each
+     * month, and adjust for the leap year that has one more day in February. */
+    int mdays[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+    mdays[1] += is_leap_year(tmp->tm_year);
+
+    tmp->tm_mon = 0;
+    while(days >= mdays[tmp->tm_mon]) {
+        days -= mdays[tmp->tm_mon];
+        tmp->tm_mon++;
+    }
+
+    tmp->tm_mday = days;
+    tmp->tm_year -= 1900; /* Surprisingly tm_year is year-1900. */
 }