[#1] Cl-nixbase32 initial iteration

#1

cl-nixbase32-test.asd

@@ -6,7 +6,7 @@
   :components ((:module "test"
                 :components ((:file "package")
                              (:file "test" :depends-on ("package")))))
-  :depends-on (:cl-nixbase32 :myam :alexandria))
+  :depends-on (:cl-nixbase32 :myam :alexandria :ironclad))
 
 (defmethod perform ((op test-op)
                     (system (eql (find-system :cl-nixbase32-test))))

cl-nixbase32.asd

@@ -11,5 +11,5 @@
                (:file "package")
                (:file "cl-nixbase32" :depends-on ("package"))
                )
-  :depends-on (:alexandria)
+  :depends-on (:alexandria :arrow-macros)
   :in-order-to ((test-op (test-op :cl-nixbase32-test))))

cl-nixbase32.lisp

@@ -1,3 +1,40 @@
 ;;; -*- Mode:Lisp; Syntax:ANSI-Common-Lisp; Coding:utf-8 -*-
 
 (in-package :cl-nixbase32)
+
+(defvar *alphabet* "0123456789abcdfghijklmnpqrsvwxyz")
+
+(defun byte-to-bits (byte)
+  "Convert a byte to a list of its bits."
+  (loop for i from 7 downto 0
+        collect (ldb (byte 1 i) byte)))
+
+(defun bits-to-int (bits)
+  "Convert a list of bits to an integer."
+  (reduce (lambda (acc bit) (+ (* 2 acc) bit)) bits))
+
+(defun pad-in-front (list)
+  (ecase (mod (length list) 5)
+    (0 list)
+    (1 (append '(0 0 0 0) list))))
+
+(defun group-by-5 (list)
+  (when list
+    (cons (subseq list 0 5)
+          (group-by-5 (nthcdr 5 list)))))
+
+(defun lookup-alphabet (list)
+  (map 'string (lambda (x) (aref *alphabet* x)) list))
+
+(defun bytes-to-nixbase32 (vector)
+  ;; Maybe I'll implement this more efficiently at some point.  For
+  ;; now, this works.
+  (arrow-macros:->> vector
+   (map 'list #'identity)
+   reverse
+   (map 'list #'byte-to-bits)
+   alexandria:flatten
+   pad-in-front
+   group-by-5
+   (mapcar #'bits-to-int)
+   lookup-alphabet))

package.lisp

@@ -2,4 +2,4 @@
 
 (defpackage :cl-nixbase32
   (:use :common-lisp :alexandria)
-  (:export))
+  (:export #:bytes-to-nixbase32))

test/test.lisp

@@ -4,5 +4,30 @@
 
 (defsuite* :cl-nixbase32-test)
 
-(deftest dummy
-  (is (= 1 1)))
+(deftest bytes-to-nixbase32.1
+  (is (equal "04000000000000000000000000000000"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "0000000000000000000000000000000000000001"))))
+  (is (equal "08000000000000000000000000000000"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "0000000000000000000000000000000000000002"))))
+  (is (equal "nvd61k9nalji1zl9rrdfmsmvyyjqpzg4"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6")))))
+
+(deftest bytes-to-nixbase32.2
+  (is (equal "0080000000000000000000000000000000000000000000000000"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "0000000000000000000000000000000000000000000000000000000000000001"))))
+  (is (equal "00h0000000000000000000000000000000000000000000000000"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "0000000000000000000000000000000000000000000000000000000000000002"))))
+  (is (equal "1ak0qjw1r1idnv0847fvyj3jsd3m7z8674c41p76hr36d98n9wk2"
+             (bytes-to-nixbase32
+              (ironclad:hex-string-to-byte-array
+               "62f264516a666468ce0d849163d03f75342d87f4db1d82c0b62d861cb8c460aa")))))