janet-hashids/hashids.janet

(def DEFAULT_ALPHABET "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")

(def DEFAULT_SEPS "cfhistuCFHISTU")

(def DEFAULT_SALT "")

(def DEFAULT_MIN_LENGTH 0)

(def MIN_ALPHABET_LENGTH 16)

(def SEP_DIV (/ 7 2))

(def GUARD_DIV 12)

(defn- swap [arr i j]
  (def a (get arr j))
  (def b (get arr i))
  (put arr i a)
  (put arr j b)
)

(defn consistent-shuffle [alphabet salt]
  (if (= "" salt) alphabet
      (let [alph-bytes (apply array (string/bytes alphabet))
            salt-bytes (string/bytes salt)
            max-index (- (length alph-bytes) 1)]
        (var p 0)

        (loop [i :down [max-index 0]]
          (let [v (mod (- max-index i) (length salt-bytes))
                n (get salt-bytes v)
                j (mod (+ n v (set p (+ p n))) i)]
            (swap alph-bytes i j)))

        (apply string/from-bytes alph-bytes))))


(defn encode [opts num]
  "j0gW")