sort byte slices in Golang without needing to fmt as string. useful for Set hashes

sortByteSlice.go

package main

import (
	"bytes"
	"log"
	"sort"
)

// implement `Interface` in sort package.
type sortByteArrays [][]byte

func (b sortByteArrays) Len() int {
	return len(b)
}

func (b sortByteArrays) Less(i, j int) bool {
	// bytes package already implements Comparable for []byte.
	switch bytes.Compare(b[i], b[j]) {
	case -1:
		return true
	case 0, 1:
		return false
	default:
		log.Panic("not fail-able with `bytes.Comparable` bounded [-1, 1].")
		return false
	}
}

func (b sortByteArrays) Swap(i, j int) {
	b[j], b[i] = b[i], b[j]
}

// Public
func SortByteArrays(src [][]byte) [][]byte {
	sorted := sortByteArrays(src)
	sort.Sort(sorted)
	return sorted
}

Less could be shortened to:

func (b sortByteArrays) Less(i, j int) bool {
	return bytes.Compare(b[i], b[j]) < 0
}

I think this entire code sample can be replaced with this:

func SortByteArrays(src [][]byte) {
	sort.Slice(src, func(i, j int) bool { return bytes.Compare(src[i], src[j]) < 0 })
}

(I think it's better to not return the sorted array, because it implies you didn't modify src, but of course you did --- src has been overwritten by the sorted array, in your implementation and in mine.)

-Ken