Implementing a Cuckoo Filter in Go(medium.com)

https://medium.com/@meeusdylan/implementing-a-cuckoo-filter-in-go-147a5f1f7a9

5 comments

aksx7 anni fa

I am all for the Go idiom that variable name length should be directly proportional to it's scope, the code samples in the post have take it a bit too far and make the code harder to read.

it would be so much more readable if the struct had more descriptive names

    type Cuckoo struct {
       buckets           []bucket
       numBuckets        uint
       entriesPerBucket  uint 
       fingerprintLength uint
       capacity          uint
    }

Insanity7 anni fa

It's a good point - and I wasn't entirely sure what to go with.

In the end, I went with the shorter variable names as they are used in the paper I've linked: https://www.pdl.cmu.edu/PDL-FTP/FS/cuckoo-conext2014.pdf

In a production version of this, longer variable names would be a good thing. :)

sagichmal7 anni fa

The global hasher var makes this code unsafe for concurrent use by multiple goroutines.

voidlogic7 anni fa

This code should just call sha1.New(). If for some reason these allocations are a performance issue it is very simple to fix that will a little pooling:

    package main

    import (
        "crypto/sha1"
        "hash"
        "sync"
    )

    func main() {
        hasher := getHasher()
        defer poolHasher(hasher)
    }

    var hasherPool sync.Pool = sync.Pool{
        New: func() interface{} {
            return sha1.New()
        },
    }

    func getHasher() hash.Hash {
        return hasherPool.Get().(hash.Hash)
    }

    func poolHasher(hasher hash.Hash) {
        hasher.Reset()
        hasherPool.Put(hasher)
    }

dchest7 anni fa

Or just use sha1.Sum https://golang.org/pkg/crypto/sha1/#Sum