code: func suffixMatchLen(a, b []byte) int {
  	if len(b) > len(a) {
  		b = b[:len(a)]
  	}
  	// i is how much of b to try to match
  	for i := len(b); i > 0; i-- {
  		// j is how many chars we've compared
  		j := 0
  		for ; j < i; j++ {
  			if b[i-1-j] != a[len(a)-1-j] {
  				goto shorter
  			}
  		}
  		return j
  	shorter:
  	}
  	return 0
  }
docs: // Looking for b at the end of a.