Cause of Zune 30 leapyear problem ISOLATED!

[Charge]

What is the problem, maybe we can help

[ghst]

hmm i don't know if i'll even have my zune 30 in four years

[MercifulBoss]

Originally Posted by twhoffman

That would prevent the infinite loop, but would introduce a new bug where it advances the year on the last day of a leap year. It would have thought today was December 31, 2009. That's better than locking up, but it also would mean that all time-limited DRM media would stop working. So, if you have a Zune Pass, none of your songs would play.

What's needed is a break within an else like this (I hope, my C's a little rusty, and was never that good to begin with):

year = ORIGINYEAR; /* = 1980 */

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

Why would doing "days >= 366" advance forward a year? Wouldn't it simply say that if days = 366 or greater than 366 then do the below code?

[twhoffman]

Originally Posted by MercifulBoss

Why would doing "days >= 366" advance forward a year? Wouldn't it simply say that if days = 366 or greater than 366 then do the below code?

You're correct. If days == 366 or days > 366, it would execute the code. That code includes advancing the year:

  days -= 366;
  year += 1;

Here's what would happen. On December 31, 2008, days == 366 and year == 2008, with the original code, it would enter the loop because days > 365, but never execute the leap year code because it expects days > 366. If you change that to days >=366, it will execute the code, which is subtract 366 from days, making it 0, and add 1 to year, making it 2009.

What you're left with is day 0, 2009. Besides the year being off, you also wind up with an invalid day, since day == 1 on January 1. Day 0 would be a day that doesn't exist. That code wouldn't cause an infinite loop, but it would think it was January 0, 2009. I'm not sure what kind of bugs that would introduce, but at the very least, the year will be 2009.

I might be wrong. As I said, my C is rusty, but I'm pretty sure that's what will happen.

[Netrix]

Originally Posted by twhoffman

I'm not sure what kind of bugs that would introduce, but at the very least, the year will be 2009.

If that is the only problem, it would be rather easy to add a check to make sure that there is no day "0". If there is, they could simply add one to the number of days, fixing that problem.

[sono2351]

just another reason why leap year babies are ruining the world...

[switchblade5984]

mine still doesnt work... funny, the 30 thats not working is my wife's pink one too

[Charge]

Thats probably cuz you opened them. Am i correct?