Add documentation for `*SETTING.DAT` files

[Holzhaus]

The PIONEER directory contains these files:

• DEVSETTING.DAT
• DJMMYSETTING.DAT
• MYSETTING.DAT
• MYSETTING2.DAT

These apparently allow the device to configure itself according to the preferences of the DJ that the plugged in device belongs to.

Some very basic reverse engineering of the format has been done here: https://github.com/Holzhaus/rekordcrate/pull/27/files#diff-811635f5c64ddc67c4db2a60451b9d96feec1542bb4728595586c7c51ff25003R17-R32

[brunchboy]

Thanks for sharing this information. If someone has time to create a pull request with new sections of the documentation covering these, it will be integrated more quickly. Otherwise, I will take a crack at it sometime when I am not behind on other projects and life in general. 😄

[Holzhaus]

I think i reversed most of the MYSETTING.DAT and MYSETTING2.DAT files. You can have a look at https://github.com/Holzhaus/rekordcrate/pull/32/files.

Basically, all of the SETTING.DAT files have the following structure: https://holzhaus.github.io/rekordcrate/rekordcrate/setting/struct.Setting.html

The actual meaning of the data depends on the file, but there are a lot of single-byte enums. Also, all used fields seem to be >= 0x80, so the first bit maybe indicate if a field contains data.

[Holzhaus]

Ok, DJMMYSETTING.DAT has been reverse-engineered as well. Only DEVSETTING.DAT is missing.

[brunchboy]

Nice, thanks for keeping me updated!

[evanpurkhiser]

Just saw your rust library @Holzhaus, awesome work on this. So great to see there's still so much of a community around reversing pioneers complicated file formats :)