diff options
| -rw-r--r-- | date.c | 19 |
1 files changed, 16 insertions, 3 deletions
@@ -92,9 +92,22 @@ void ConvertDateToYMD(Date date, YearMonthDay *ymd) int rem = date % (365 * 400 + 97); uint16 x; - /* There are 24 leap years in 100 years */ - yr += 100 * (rem / (365 * 100 + 24)); - rem = rem % (365 * 100 + 24); + if (rem >= 365 * 100 + 25) { + /* There are 25 leap years in the first 100 years after + * every 400th year, as every 400th year is a leap year */ + yr += 100; + rem -= 365 * 100 + 25; + + /* There are 24 leap years in the next couple of 100 years */ + yr += 100 * (rem / (365 * 100 + 24)); + rem = (rem % (365 * 100 + 24)); + } + + if (!IsLeapYear(yr) && rem >= 365 * 4) { + /* The first 4 year of the century are not always a leap year */ + yr += 4; + rem -= 365 * 4; + } /* There is 1 leap year every 4 years */ yr += 4 * (rem / (365 * 4 + 1)); |