Unknown game variant for Adibou2readcount67 addon (gob)

[ripleyXLR8]

Hello,

While trying to play the French version of Adibou 2 : Read/Count 6-7 Yo (adibou2readcount67), I encountered an "unrecognized game variant" error.

I dumped the MD5 hashes of my files and found the following:

• intro_ap.stk : 0e91d0d693d5731353ad4738f4aa065c (Size: 36540132)
• appli_03.vmd : d037d75824a033a5de4a45b9c02419ee (Size: 58858)

Looking at the current detection tables for the gob engine (in tables_adibou2.h), the listed entry is:

AD_ENTRY2s("intro_ap.stk", "0e91d0d693d5731353ad4738f4aa065c", 36540132,
           "appli_03.vmd", "6bf95a48f366bdf8af3a198c7b723c77", 58858),

My intro_ap.stk matches the listed hash perfectly. However, my appli_03.vmd has exactly the same size (58858 bytes) but a different hash (d037d...).

The "Smoking Gun":
As shown in the attached screenshot, the hash currently in the code (6bf95a48f366bdf8af3a198c7b723c77) appears to be a copy-paste placeholder. It is identical to:

• o1.pod in the Hadesch engine (Size: 5 621 074)
• cdlogo.res in the Teenagent engine (Size: 64 768)

It is mathematically impossible for these three files of different sizes to share the same MD5. This confirms that the Adibou 2 entry needs to be updated with the correct hash (d037d75824a033a5de4a45b9c02419ee).

Could you please update the detection table?

Thanks for your amazing work!

[sdelamarre]

In 9236ba8a:

GOB: Add another French variant of Adibou 2 Read/Count 6-7 years add-on

Provided by ripleyXLR8 in #16764

[ripleyXLR8]

Replying to sdelamarre:

In 9236ba8a:

GOB: Add another French variant of Adibou 2 Read/Count 6-7 years add-on

Provided by ripleyXLR8 in #16764

See my modified ticket. It seems to be a wrong hash.

[sdelamarre]

Hello!

It seems that you have a version of this add-on ("Lecture/Calcul 6-7 ans") slightly different from the ones already recorded in our detection tables (whose appli_03.vmd was different indeed, while intro_ap.stk matched).

I have added it to our detection tables, it will be included in the next daily build, which will make the warning disappear when launching the game.

In the meantime, you can read our Adibou 2 wiki entry to make sure your file are organised as they should in the game directory:

​https://wiki.scummvm.org/index.php/Adibou_2

In particular, the files of the add-on must be moved into a freely-named subdirectory of the main game directory - your initial message mentioning the add-on to be located in "D:/", made me think it was not the case.

[ripleyXLR8]

Hello sdelamarre, and thank you for the quick addition!

I'm glad it will be included in the next build. Just to assure you, my files are properly sorted in subdirectories; the "D:/" was just a temporary testing environment I used to dump the MD5 hashes.

I wanted to draw your attention to my previous edit on the main ticket (you probably didn't get a notification for the edit). I strongly suspect the other older entry currently in the code for appli_03.vmd (6bf95a48f366bdf8af3a198c7b723c77) is actually a copy-paste placeholder and not a real existing variant.

If you search for this exact hash in the ScummVM GitHub repo, you will see it is identical to cdlogo.res in the Teenagent engine and o1.pod in the Hadesch engine. Since all three files have vastly different byte sizes, it's mathematically impossible for them to share the same MD5.

You can keep both variants in the code if it's safer, but I just wanted to point out this leftover anomaly in the detection tables! Thanks again for your time and your work on the Gob engine.

Replying to sdelamarre:

Hello!

It seems that you have a version of this add-on ("Lecture/Calcul 6-7 ans") slightly different from the ones already recorded in our detection tables (whose appli_03.vmd was different indeed, while intro_ap.stk matched).

I have added it to our detection tables, it will be included in the next daily build, which will make the warning disappear when launching the game.

In the meantime, you can read our Adibou 2 wiki entry to make sure your file are organised as they should in the game directory:

​https://wiki.scummvm.org/index.php/Adibou_2

In particular, the files of the add-on must be moved into a freely-named subdirectory of the main game directory - your initial message mentioning the add-on to be located in "D:/", made me think it was not the case.

[sdelamarre]

Since all three files have vastly different byte sizes, it's mathematically impossible for them to share the same MD5.

Actually, it is possible, as we only hash the first 5000 bytes of the files... and I just understood that it's the hash one obtains for a file starting with 5000 0's!

So you were right to point this out, the hash was correct, but the "appli_03.vmd" file that was used as a basis to compute it for this entry was likely corrupted.

I'll leave the entry it as-is, in case it is a widespread corruption (and the actual content of the file does not really matters for the gameplay, as far as I remember). The main point is that we now also have the hash of the non-corrupted version of the file.
Thank you!

[sdelamarre]

In c12b658:

GOB: Remove an Adibou2 detection entry based on a corrupted file

A corrupted appli_03.vmd (full of 0x00's) was used to compute the hash,
see #16764.

[sdelamarre]

Update: after checking again the history, it appears that the corruption originated from a particular copy on my own drive, not present on the original medium. I guess it was caused by an interrupted copy operation, or some cloud sync problem. So there is no reason indeed to keep the previous entry, I just have removed it.