Created
July 31, 2019 16:42
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Replicating Java's String.hashCode() method for a cljc project
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(ns tst.demo.core | |
(:use demo.core tupelo.core tupelo.test) | |
(:require [tupelo.core :as t]) ) | |
(defn str->hashcode | |
"Work-alike impl of Java String.hashCode() fn" | |
[str-val] | |
(let [char-codes (mapv int str-val) | |
step-fn (fn step-fn [hash-in char-code] | |
(let [hash-out (+ char-code | |
(- | |
(bit-shift-left hash-in 5) | |
hash-in)) | |
hash-out (bit-and hash-out 0xFFFFFFFF)] | |
hash-out)) | |
result (reduce step-fn 0 char-codes)] | |
result)) | |
(dotest | |
(spy "hello") | |
(spyx (str->hashcode "hello")) | |
(spyx (.hashCode "hello")) | |
) | |
;------------------------------- | |
; Clojure 1.10.0 Java 12 | |
;------------------------------- | |
; | |
; Testing tst.demo.core | |
; :spy => "hello" | |
; (str->hashcode "hello") => 99162322 | |
; (.hashCode "hello") => 99162322 |
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