Hello, I'm wondering if one of you could share with me the block checksum algorithm.

My goal is to make a training tool that lets you watch your ladder replays, with an annotate info-board showing live stats from the game. For example current resources, total HP of all units.  Eventually it can include graphs, analysis etc so that you can more easily identify points in the game where you need to do better.

This training tool must run within a custom map.  Hence I need to rewrite the replay file to have a different map reference, which I why I need to compute a new checksum.

Best regards,
--David J.

Here's my plan, and how the block checksum algo is necessary.

1. I play a ladder game, let's say it's on Echo Isles.  I save the replay.
2. I have a custom map, my own version of Echo Isles that includes custom JASS code for displaying an infoboard with useful stats, graphs, etc about the game.
3. I modify the replay file so that it thinks the game was played on my custom map.
4. I watch the replay, and I get to see all the cool stats.

So as you can see, in step 3 I am modifying a replay file.  Without the block checksum algo, the Warcraft engine will refuse to play the replay because the checksum will be wrong.

Ooh, I have no idea how to do that -- can you link me to any relevant info/tutorials?   I know there are mpq editors out there, but I guess I need a guide to the built-in mpqs.

Boom I finally got the algorithm by debugging WC3 (it took several hours, and it was the first time I ever tried disassembling anything).
But I suppose there are people who don't think its a good idea for such information to be open to public.

Well, its one thing to disassemble stuff (violating the EULA), its another to post it to a public website. This can especially become a problem for the owner of the website. The BNETD server development was stopped by blizzard by filing a law suite against the website owner - but thats an old story.

I would still vote against making the checksum algorithm public for the same old reason: right now replays are quite unmodifiable and such a good proof for any kind of player dissensions. Making them modifyable makes you loose this proof...

I'd be interested in seeing the algorithm so that I could automate the map hashing functionality in wc3 game hosting applications.