A clojure implementation of Reed-Solomon and BCH codes, for educational purposes.
It also come with a QR code generator!
The associated blogpost is here: https://meiji163.github.io/post/ecc/
(require '[ecc-clj.poly :as p])
(require '[ecc-clj.core :as ecc])
;; encode a message with (255,233) Reed-Solomon code
(def my-encoded-msg
(let [message
(str
"Hello world! This is meiji163 transmitting from Neptune. "
"It's cold here, Please send hot chocolate. Thanks. "
"Now that I think of it, ramen would be good too if you have some.")
data (vec (map int message))
padded (p/shift-right
data
(- 223 (count data)))]
(ecc/encode padded ecc/RS-255-223 ecc/GF256)))
;; correct message with errors
(let [err [0 42 1 0 0 163 0 0 66 0 0 0 0 0 101 100]
max-errs 8
decode-me (p/+ my-encoded-msg err ecc/GF256)]
(ecc/decode decode-me max-errs ecc/GF256))
;; => {:locations [1 2 5 8 14 15],
;; :sizes [42 1 163 66 101 100]}
;; create a QR code
(import java.io.File)
(import java.imageio.ImageIO)
(require '[ecc-clj.qr :as qr])
(let [mask-code 1
databits (->> "github.com/github"
(map int)
(qr/encode-bytes)
(qr/mask-bits mask-code))
fmtbits (qr/fmt-bits mask-code)
myimg (qr/qr-image fmtbits databits)]
(ImageIO/write myimg "PNG" (File. "test.png")))Run tests with lein test
Copyright © 2023 FIXME
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.
This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.