adler32.clj

(def base 65521)
(defn adler32 [data]
  (let [a (atom 1)
        b (atom 0)
        i (atom 0)
        l (count data)
        m (bit-and @l -4)]
    (while (< @i @m)
      (let [n (min (+ @i 4096) @m)]
        (while (< @i @n)
          (swap! b + (+
                      (swap! a + (int (.charAt data @i)))
                      (swap! a + (int (.charAt data (+ @i 1))))
                      (swap! a + (int (.charAt data (+ @i 2))))
                      (swap! a + (int (.charAt data (+ @i 3))))))
          (swap! a mod base)
          (swap! b mod base)
          (swap! i + 4))))
    (while (< @i @l)
      (swap! b + (swap! a + (int (.charAt data @i))))
      (swap! i inc))
    (swap! a mod base)
    (swap! b mod base)
    (bit-or @a (bit-shift-left @b 16))))