bitmask_permutations.go

package main

import "fmt"

func nextPermutation(x byte) byte {
	a := x & -x
	b := x + a
	c := b ^ x
	a <<= 2
	c /= a
	return b | c
}

func main() {
	count := 0
	for cur, lst := byte(7), byte(127); cur < lst; cur = nextPermutation(cur) {
		fmt.Printf("%08b\n", cur)
		count++
	}
	fmt.Printf("Total %d permutations\n", count)
}

Live code: http://play.golang.org/p/-4eojhS82r