dryman

Awesome. This will be a super useful reference once I want to migrate the library to C++.

If I use a strict subset of C++, probably will do. However, figuring out the subset of different C++ standards and implementation that doesn't include extra pointers is hard. I might need to re-implement some useful utilities like unique pointer and share pointers as well. Some fundamental data structure in C++ includes pointers as well, like short string optimization introduce extra pointers. With my poor C++ knowledge, I don't even know what are the other pointers are missing..

The problem is C++ brings in many extra pointers. For example, the vtable pointer used in virtual functions. All the pointers not converted to offset can be invalid in next process that deserializes the object.

Author here. I did think about creating a programming language specialized for serialization. Fortunately, using just C seems to be sufficient for building a POC. Another advantage for using C is it is easier to embed into other languages. OPIC is more library focused, which would benefit for integrating into other languages. Jai language seems to be a application (gaming) focused language, and the language abstraction makes developer faster to code is more important.

Lemire's fast range works perfectly with cuckoo, as it doesn't require probing (?). The fast mod and scale trick was invented to address this issue.

It's actually pretty funny. I didn't know Lemire's trick until I start to write this article. But I my first try on fixed point arithmetic was exactly the same as his work. Then figured out the lower bits would get omitted with fast range (I named it scaling). Finally I came up with this fast mod and scale idea.

I don't know for other peoples need on non power of 2 tables. My target is to build large scale hash tables and other data structures. The memory and data compactness is quite critical for this goal.

Thanks for pointing out the thread-unsafe alternative. I'll update the benchmark with it and double I configured it with cityhash. (will update in a day or two).

Speaking of cityhash, have you tried farmhash as well? I'm not sure what I did wrong, but farmhash's performance wasn't good as cityhash in my hash table. Did you experience the same problem?

In my experiments using linear probing in robin hood doesn't give good results as well. I hope the author has tried robin hood with quadratic probing. But it's a good reference. I didn't dive deep in the cuckoo route. This paper gives me more confidence to try it out.