[LEAPSECS] Leap year day-count bugs, then and now

[Tom Van Baak]

> Also, the comments section of that article includes the actual code 

> behind the Zume bug, which involves the system getting put in an 

> infinite loop on reaching a day number of 366, even though the code 

> did in fact attempt to be cognizant of leap years.


Dan, thanks for the rtt.c link (http://pastie.org/349916.txt)
The piece of code in question starts at line 259:

    while (days > 365)
    {
        if (IsLeapYear(year))
        {
            if (days > 366)
            {
                days -= 366;
                year += 1;
            }
        }
        else
        {
            days -= 365;
            year += 1;
        }
    }

The file contains quite a number of date/time related functions,
not unlike those found in almost any application, library, or
operating system.

I recommend anyone on the list take a look at this file, not as a
swipe at Zune or the company that makes it, or Freescale, who
apparently wrote the code, but as a typical example of the state
of date/time handling in modern software.

Then, if leap seconds were to matter to a device like Zune, ask
yourself what would have to change in the code the handle leap
seconds correctly as well as leap years.

/tvb