> using one buffer for multiple strings is just a type specific arena allocator.

Sure, but there's a lot of advantages of entirely controlling memory allocation in-process.

> this approach is going to be EXTREMELY wasteful.

Could you elaborate why? Sure, you have to do a bit more juggling in-process, but I would imagine this would be potentially more efficient than having conventional mallocs.

In the environment it is designed to operate in, there is usually a fixed memory limit per process, so you might as well grab all that up front.