[Tilecache] Tile naming

[Roeland Douma]

Hi,

I'm trying to write a simple python script that parses the diffs of open 
streetmap and deletes the tiles that contain data that is no longer up to 
date. In order to do this I calculate the x and y ( 
http://wiki.openstreetmap.org/index.php/Slippy_map_tilenames ) and for all 
zoom levels.

Now the values that I get out of that are the values I need because if I enter 
them on 

http://tile.openstreetmap.org/10/525/336.png
and
http://tile.famdouma.nl/tilecache.cgi/1.0.0/osm/10/525/336.png

it is the same time (the second one has a bbox).

However when I check my tilecache dir the file i want is:
10/000/000/525/000/000/687.png

I use Disk as caching mechanism. And when I look into the source the format 
is: zz/xxx/xxx/xxx/yyy/yyy/yyy.png
And the caching does not manipulate it.

The zoom and x see to be the same but I can't find how the y is calculated.

Any ideas?

Thanks in advance,
rullzer