[Bug 740] Changed - divide by zero exception in x11drv.dll

[wine-bugs at winehq.com]

http://bugs.winehq.com/show_bug.cgi?id=740

*** shadow/740	Fri May 31 13:26:39 2002
--- shadow/740.tmp.7952	Fri May 31 13:26:50 2002
***************
*** 251,253 ****
--- 251,300 ----
  
  ------- Additional Comments From Speeddymon at yahoo.com  2002-05-31 13:26 -------
  Adding Andriy to CC's
+ 
+ ------- Additional Comments From Speeddymon at yahoo.com  2002-05-31 13:26 -------
+ ok, I have some info on the problem...
+ 
+ here is basically what happens:
+ 
+ fgBits gets initialized ;)
+ fgBits gets set to zero
+ then things screw up...
+ 
+ but you knew that I know, just keep reading...
+ 
+ 2 lines below where fgBits gets set to zero, xmax gets set to whatever, 
+ possibly zero, same with ymax...
+ 
+ then we run a for on y=0 and compare it to ymax
+ inside there we run a for on x=0 and compare it to xmax...
+ then theres a switch that may be important to this bug
+ and then the crucial if (red+green+blue > threshold)
+ which is the only place that fgBits gets incremented before that divide by zero 
+ error, so obviously 1 of 3 things is happening:
+ 
+ 1) ymax is being set to zero and so the for fails
+ 2) xmax is being set to zero and so the for fails
+ 3) red+green+blue is not being set high enough to pass the threshold if
+ 
+ and so fgBits++ isn't taking place...
+ 
+ now that I have looked back up at the switch, I see that lo and behold:
+ 
+ theChar = theImage[byteIndex++];
+ red = theChar;
+ 
+ and like david said above, the whole theImage array is failing...
+ 
+ now, since I don't have access to a Linux box ATM (i have to go home to access 
+ it) I can't add my own trace messages to see what is causing theImage to fail, 
+ but it looks like either
+ 
+ 1) byteIndex++ isn't working for some really weird reason
+ 2) byteIndex++ is working, but theImage[1] doesn't exist
+ 3) &theMask[ptr->nWidth/8 * ptr->nHeight]; isn't working...
+ 
+ So... I will add my stuff tonight and try to post the results tomorrow....
+ 
+ all of this information is against the current mouse.c, not rev 1.2 which is 
+ the first version with this problem...
\ No newline at end of file