Persisting Objects while Still Preserving Loose Coupling

Question

I working on a project in a microcontroller and I need to persist some settings. Pretend this is an iPod. I need to save various settings like CurrentSongPlaying, CurrentVolume, etc. so that when I turn on again I can restore those settings. The trouble I'm running into is that makes sense to store all my Non-Volatile Settings in a single struct that I can serialize/de-serialize from memory but I can't find a way to make that happen without the class doing the serialization/de-serialization from non-volatile memory including every class that contains a setting that will need to be saved for size/type information. Is there some sort of design pattern that will allow me to persist all these settings to memory without having to know about what I'm saving?

Answer 1

Looks like you just need an associative array. An associative array (or map) is a container that allows you to map different values to unique keys. It can have a fixed or dynamic size depending on the implementation. Coupled with a proper serialization mechanism, it allows you to save and restore its state without having to know its content in advance.

However, C does not provide this data structure out-of-the-box. Look at this question for a few implementations. The most common implementation is the hash table, also called a hash map.

Answer 2

OOP and classes are not easy to implement in C.

If using C is a must, I would write the struct to file.

Then I would read them and parse them during initialization upon reboot.

You can think of this as serializing your structs yourself.