package main var keyChar = []byte("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ") func genKey(n int) string { if n == 0 { return string(keyChar[0]) } l := len(keyChar) s := make([]byte, 20) // FIXME: will overflow. eventually. i := len(s) for n > 0 && i >= 0 { i-- j := n % l n = (n - j) / l s[i] = keyChar[j] } return string(s[i:]) }