slotmap VS BLAKE3

It looks like .get_disjoint_mut() from slotmap failed under stacked borrows, but seems to pass under tree borrows

I think slotmap is meant to solve this exact issue. Basically when you insert into a collection you get an Id:Version tuple as key. When you reuse a slot, next time the key will be Id:Version+1 and when you try to access the removed value by using Id:Version, it will return None. You can think about it as delayed invalidation.

Dunno about existing implementations, but it looks like it's a feature they'd accept: https://github.com/orlp/slotmap/issues/73

It's actually quite easy.

You can use either slot map or slab to side step rust borrow checker. Example https://github.com/orlp/slotmap/blob/master/examples/rand_meld_heap.rs

I don't know, only have some theories.

1. The name isn't particularly catchy or descriptive. It is the correct name for the data structure, but not too many people know the data structure.

2. People don't even know what they're missing. It's not a very Google-able problem to begin with. Slotmap provides an interesting solution to (circular) ownership and safe allocator / weak pointer design problems, but people don't recognize that they're having them or that slotmap could help.

As an example of this, the doubly linked list example (https://github.com/orlp/slotmap/blob/master/examples/doubly_...) can safely remove nodes from the linked list given their handle, in O(1), even from the middle, completely safely and correctly, even in the presence of double deletions or ABA memory re-use. You can't replicate this with just pointers, without introducing heavy refcounting solutions.

Nope, it's perfectly safe: https://github.com/orlp/slotmap/blob/master/examples/doubly_linked_list.rs.

I think keeping the relationship between child and parent elements in the node graph might be better accommodating better via a psuedo-ECS system, see https://www.reddit.com/r/rust/comments/cnjhup/idiomatic_way_to_reference_parent_struct/. The https://github.com/orlp/slotmap crate looks promising. I think I'm just going to ditch the global shared HashMap in favor of something that can better accommodate child/parent relations.

I think the slotmap crate is similar to what you're trying to write: https://github.com/orlp/slotmap

> might be easier with a public domain license instead of the current ones

There reference implementation is public domain (CC0) or at your choice Apache 2.0

https://github.com/BLAKE3-team/BLAKE3/blob/master/LICENSE

Fyi, blake3 was released in 2019 and should probably be used over blake2 unless you have some strong reason not to. It's basically a reimplementation of blake2 with performance tweaks.

https://github.com/BLAKE3-team/BLAKE3

Many people will argue that today's compilers are so smart/optimized that you'd be a fool to try to outsmart the compiler with asm. I'm not 1 of them, but I know some. IMO it's all a bunch of bullshit, there's a goddamn reason all the cryptocurrency mining CPU/GPU code is all hand-written asm. there's a reason blake3 is written in asm ( https://github.com/BLAKE3-team/BLAKE3/blob/master/c/blake3_sse41_x86-64_windows_msvc.asm ) - but the thing is, 99.99% of the time, life is too short to outsmart the compiler (unless you're Alexander Yee)

I have been trying to optimize my code to create a fast hashing function to create and check b3 file integrity but b3sum is way way faster than my aproach, i have been trying to modify my code acordingly to https://github.com/BLAKE3-team/BLAKE3/blob/master/b3sum/src/main.rs with no luck, so if anyone can give me some tips/clues on how to achieve better speeds it would be incredible. Thx!!

BLAKE3 might be faster than KangarooTwelve and is also an XOF. It doesn't have the benefit of getting a working RFC draft proposal however.

You're saying the hash speed is 133 kB/s? That's extremely slow, for example BLAKE3 achieves 6.8 GB/s which is over 50000 times faster. Nobody wants to use such a slow hash function.

Try this one if you want a smaller, and particularly interesting crate: https://github.com/BLAKE3-team/BLAKE3

blake3 is a cryptographic hashing function, which is used during plotting's "forward propagation" step

BLAKE3 claims to be faster and more secure than both MD5 and SHA1.

More information: https://github.com/BLAKE3-team/BLAKE3