C++ serialization library that supports partial serialization? [closed]

Question

Are there any good existing C++ serialization libraries that support partial serialization?

By "partial serialization" I mean that I might want to save the values of 3 specific members, and later be able to apply that saved copy to a different instance. I'd only update those 3 members and leave the others intact.

This would be useful for synchronizing data over a network. Say I have some object on a client and a server, and when a member changes on the server I want to send the client a message containing the updated value for that member and that member only. I don't want to send a copy of the whole object over the wire.

boost::serialization at a glance looks like it only supports all or nothing.

Edit: 3 years after originally writing this I look back at it and say to myself, 'wut?' boost::serialization lets you define what members you want saved or not, so it would support 'partial serialization' as I seem to have described it. Further, since C++ lacks reflection serialization libraries require you to explicitly specify each member you're saving anyway unless they come with some sort of external tooling to parse the source files or have a separate input file format that is used to generate C++ code (e.g. what Protocol Buffers does). I think I must have been conceptually confused when I wrote this.

Answer 1

You're clearly not looking for serialization here.

Serialization is about saving an object and then recreating it from the stream of bytes. Think video games saves or the session context for a webserver.

Here what you need is messaging. Google's FlatBuffers is nice for that. Specify a message that will contain every single field as optional, upon reception of the message, update your object with the fields that do exist and leave the others untouched.

The great thing with FlatBuffers is that it handles forward and backward compatibility nicely, as well as text and binary encoding (text being great for debugging and binary being better for pure performance), on top of a zero-cost parsing step.

And you can even decode the messages with another language (say python or ruby) if you save them somewhere and want to throw together a html gui to inspect it!

Answer 2

Although I'm not familiar with them, you could also check out Google's Protocol Buffers .