fst VS rust-fnv

I'd point you towards BurntSushi's fst crate: https://github.com/BurntSushi/fst

The fst crate effectively relies on mmap for it to work right. The folks here suggesting you just use the heap might be right, but only if using the heap is actually plausible. If your dictionary is GBs big (an FST might be bigger than available memory), then copying it the heap first would be disastrous.

You'll love what we're working on if you're interested in the implementation of:- Tantivy- Meilisearch- Finite State Transducers

Here's an example of longest prefix matching using a FST which I based my approach on: https://github.com/BurntSushi/fst/pull/104/files

Finite State Transducers

As a result, I have a plan to implement a desktop version from then and I finished today with a beta version. The desktop is based on tauri, and the dictionary index algorithm is FST (it is an awesome index algorithm).

WordBueno’s data is currently derived from Wiktionary. The backend is using Rust’s warp with fst for indexing.

No you don't. I've written multiple programs that load things instantly off the file system via memory maps. See the fst crate[1], for example, which is designed to work with memory maps.

Rust "works badly with memory mapped files" doesn't mean, "Rust can't use memory mapped files." It means, "it is difficult to reconcile Rust's safety story with memory maps." ripgrep for example uses memory maps because they are faster sometimes, and its safety contract[2] is a bit strained. But it works.

[1] - https://github.com/BurntSushi/fst/

[2] - https://docs.rs/grep-searcher/0.1.7/grep_searcher/struct.Mma...

Use faster hashing function (e.g. fnv, there are other potentially faster options as well). By default Rust std uses a DoS-resistant function, which is relatively slow.

Looking at ripgrep myself, I'm seeing some trivial dependencies. One is fnv. Perhaps you're not aware, but FNV-1a is literally ~4 lines of code. It's about as sophisticated as left-pad. I've written it from scratch a dozen times off the top of my head (the official offset basis and prime are really not special, so you can just generate your own). It would take you about a minute to eliminate it.