[nneonneo]

This isn't uncommon, especially for file formats which are meant for internal consumption. Of course, they end up being huge cans of worms in terms of security, stability and maintainability going forward.

Basically, instead of defining a real serialization format (and thus having to write serializer/deserializer code), it's way easier to just `fwrite` out your internal structs to disk, one after another, and write some much simpler walker code to walk through any pointed fields appropriately. At some point though this becomes technical debt which needs to be repaid in the form of a total serialization rewrite.

Blender, the popular open-source 3D modelling tool, uses a format like this for their .blend files, and it is really gross. IIRC a few releases back they started working to improve the format to be a little less dependent on low-level internal details, but now they have the nightmare of backwards compatibility to deal with.

The basic problem is that C/C++ have no mechanism for native serialization, unlike e.g. Java, Python, or any number of other languages, so you're either stuck `fwrite`ing structs or reinventing the wheel.

[StillBored]

Which is mostly due to the lack of run-time reflection. OTOH, with a little creativity its possible to create code generators to attach a commonly named (say .serialize method) to classes to dump their POD fields, and call serialize on directly encapsulated classes.

But your basically right, everyone ends up doing it their own way which just ends up being a PITA.