Save File Optimizations

[gheskett]

Save files should be optimized and allow for removal of backup saves via define.

EDIT: One issue that came up when discussing this is compatibility with Star Display programs. A plan will need to be figured out for this. @thecozies suggested potentially creating a script that builds a file to be used in Star Display, based on the save file structure. Do not put backup removal in master until this is solved, or unless save files are padded by default via define to match the expected save structure (this should probably exist regardless, since the average joe might not bother wanting to submit a star layout).

Additional requirement: Save file structs must be forced to use 8-byte alignment in some way or another (unless padding mentioned above is also written to the savefile).

[gheskett]

Related issue: #317

[gheskett]

Still unclear whether this is actually worth following through on, since it will break save trackers for saves not using Save File A

[arthurtilly]

this is something i do plan on doing (not as a define), i think we had a long discussion about this and planned to add padding to the save file to make it still compatible with save trackers by default but have the padding easy to remove

[gheskett]

Still think the best approach is to have one backup encompassing all four, though iirc? there was some other drawback that I can't remember anymore

[gheskett]

Another one actually is not writing backup saves means save file sizes must be 8-byte aligned rather than just 4 like before

[arthurtilly]

adding one big backup with a weird implementation would ruin the entire point of this (that is, to make it trivial to increase the save file size significantly)

[gheskett]

It should still be easy if implemented properly, I don't see why it wouldn't. Just place 1 backup slot after the four main saves.

[arthurtilly]

i don't see how thats preferrable over the vanilla implementation and it doesnt solve the issue of being incompatible with star tracker software

[gheskett]

It's preferable over vanilla still because it's equivalent to 5 save slots instead of 8

[arthurtilly]

i guess, but having no backups means more code can be cleaned up, more space for save file expansion, more feasible to retain star tracker support and backups are not a very useful feature anyway

[gheskett]

Yeah I'm mostly just worried about save file corruption but I can probably live without it if it's for sure minor enough

[arthurtilly]

to be clear if backups are removed save file corruption would cause the save to be wiped automatically, it wouldnt just randomly give incorrect stars or anything

[gheskett]

Yeah, where I definitely draw the line is removing checksums

[arthurtilly]

removing checksums isnt even possible, the game relies on them to initialise the save data from EEPROM garbage