USIO: Save Game Settings - Full Implementation (Supplement to #12686)

[brian218]

This PR implemented permanent USIO game data saving, serving as a supplement to #12686.

[Nekotekina]

I suppose it should be written to file immediately once any changes are made

[brian218]

I suppose it should be written to file immediately once any changes are made

Wouldn't this cause performance compromise during the game?
The game writes data to these two buffers (backup_memory and last_game_status) frequently no matter whether a change is made by a player.

[RipleyTom]

I suppose it should be written to file immediately once any changes are made

Wouldn't this cause performance compromise during the game? The game writes data to these two buffers (backup_memory and last_game_status) frequently no matter whether a change is made by a player.

You could just compare size and content and if it changes write to file?

[brian218]

I suppose it should be written to file immediately once any changes are made

Wouldn't this cause performance compromise during the game? The game writes data to these two buffers (backup_memory and last_game_status) frequently no matter whether a change is made by a player.

You could just compare size and content and if it changes write to file?

@RipleyTom The sizes of backup_memory(0xB8) and last_game_status(0x28) are constant, so the total size is always 0xE0(0xB8 + 0x28).
We cannot discriminate changes by comparing their sizes.

As for the content, since a timestamp is included, the game changes the content and writes it to the endpoints frequently.

[Nekotekina]

Hmm, perhaps a memory mapped file can be used as an alternative.

[brian218]

Hmm, perhaps a memory mapped file can be used as an alternative.

@Nekotekina Could you suggest an example? Thank you.
By the way, if frequent writing to the backup file won't compromise the performance during the game, I can of course make it write changes to the backup file each time any change is made by the game.

[elad335]

File writes can be async if this function changes content so frequently.

[Nekotekina]

Actually nevermind, it would need quite a bit of work. I can implement it later. PR can be merged as is.

[brian218]

Actually nevermind, it would need quite a bit of work. I can implement it later. PR can be merged as is.

@Nekotekina Thanks!