FNV-1 hashing function - an implementation in Go that matches the output of using the builtin fnv package

fnv_hash.go

package main

import (
	"fmt"
	"hash/fnv"
)

func main() {

	// the data to be hashed
	data := []byte("Hello world")

	// the Go in-built FNV hashing function
	hash := fnv.New64()
	hash.Write(data)
	x := hash.Sum64()
	fmt.Println(x)

	// my implementation based on the pseudocode on wikipedia (see: https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function)
	const FNVPrimeOffset uint64 = 14695981039346656037
	const FNVPrimeValue uint64 = 1099511628211
	var h uint64 = FNVPrimeOffset
	for _, b := range data {
		h = h * FNVPrimeValue
		h = h ^ uint64(b)
	}
	fmt.Println(h)
	
	// interestingly a supposedly superior distribution of hashes is achieved by changing the order of two lines.
	// This is known as the FNV-1a hash algorithm
	const FNVPrimeOffset uint64 = 14695981039346656037
	const FNVPrimeValue uint64 = 1099511628211
	var h uint64 = FNVPrimeOffset
	for _, b := range data {
		h = h ^ uint64(b)
		h = h * FNVPrimeValue
	}
	fmt.Println(h)	
}