chan_hash.clj

(ns chan_hash)

(import '[org.apache.commons.codec.binary Hex])
(import '[java.nio ByteBuffer])
(require '[clojure.core.async :as async :refer [chan go >! <! pipeline go-loop <!!]])

(def sha256-digest (java.security.MessageDigest/getInstance "SHA-256"))

(defn hexify [bb]
  (Hex/encodeHexString bb))


(defn sha256 [message]
  (.digest sha256-digest message))

(defn int->bytes [i]
  (let [buffer (ByteBuffer/allocate 4)] ;; ints are 4-byte long
    (.putInt buffer i)
    (.array buffer)))

(def in-chan (chan))
(def out-chan (chan))

(def transform (comp hexify sha256))

(pipeline 4 out-chan (map transform) in-chan)

(doseq [i (range 1000)]
  (go (>! in-chan (int->bytes i))))

(go-loop []
  (println (<! out-chan))
  (recur))


(Thread/sleep 5000)

deps.edn

{:deps
 {org.clojure/core.async {:mvn/version "1.3.610"}
  commons-codec/commons-codec {:mvn/version "1.15"}}}