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(svn r7731) -Fix (r5999): off-by-one error in the date to YMD calculation for first 4 years of a century that was not divisable by 400.

This commit is contained in:
rubidium 2007-01-01 22:00:54 +00:00
parent 67a1115408
commit a542c74949
1 changed files with 16 additions and 3 deletions
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19
date.c
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@ -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));