File Comperator Revisited (like Kazaa uses)

This code will compare files. When two files on the local hdd must be compared you could do a bit wise comparisation. Over the internet for large files this is impossible. So this is where hashing comes in. Most programs use something like this (Kazaa does to) and I use it in my file transfer resuming messenger. Files renaming doesnot make any sense anymore and you can check wheter a partial donwloaded file is the same as a complete file. It is all kinda advanced, but works very good. Just check it out. Votes and comments are appreciated