Data commit

Task/IBAN/Common-Lisp/iban.lisp

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+;;
+;; List of the IBAN code lengths per country.
+;;
+(defvar *IBAN-code-length* '((15 . ("NO"))
+                             (16 . ("BE"))
+                             (18 . ("DK" "FO" "FI" "GL" "NL"))
+                             (19 . ("MK" "SI"))
+                             (20 . ("AT" "BA" "EE" "KZ" "LT" "LU"))
+                             (21 . ("CR" "HR" "LV" "LI" "CH"))
+                             (22 . ("BH" "BG" "GE" "DE" "IE" "ME" "RS" "GB"))
+                             (23 . ("GI" "IL" "AE"))
+                             (24 . ("AD" "CZ" "MD" "PK" "RO" "SA" "SK" "ES" "SE" "TN" "VG"))
+                             (25 . ("PT"))
+                             (26 . ("IS" "TR"))
+                             (27 . ("FR" "GR" "IT" "MR" "MC" "SM"))
+                             (28 . ("AL" "AZ" "CY" "DO" "GT" "HU" "LB" "PL"))
+                             (29 . ("BR" "PS"))
+                             (30 . ("KW" "MU"))
+                             (31 . ("MT"))))
+
+;;
+;; The IBAN-character function verifies whether the number contains the correct characters only. There is
+;; a built in function to verify for alphanumeric characters, but it includes characters beyond ASCII range.
+;;
+(defun IBAN-characters (iban)
+  (flet ((valid-alphanum (ch)
+           (or (and (char<= #\A ch)
+                    (char>= #\Z ch))
+               (and (char<= #\0 ch)
+                    (char>= #\9 ch)))))
+    (loop for char across iban
+          always (valid-alphanum char))))
+
+;;
+;; The function IBAN-length verifies that the length of the number is correct. The code lengths
+;; are retrieved from the table *IBAN-code-lengths*.
+;;
+(defun IBAN-length (iban)
+  (loop :for  (len . country) :in *IBAN-code-length*
+        :with iban-country = (subseq iban 0 2)
+        :do
+    (when (find iban-country country :test #'string=) (return (= len (length iban))))))
+
+;;
+;; The function IBAN-to-integer converts an IBAN code into an integer number.
+;; Note: The conversion follows the rules stated in the wiki page.
+;;
+(defun IBAN-to-integer (iban)
+  (let ((character-base (- (char-code #\A) 10)))
+    (parse-integer
+      (format nil "~{~a~}" (map 'list #'(lambda(X) (if (alpha-char-p X) (- (char-code X) character-base) X ))
+                                      (concatenate 'string (subseq iban 4) (subseq iban 0 4)))))))
+;;
+;; The function IBAN-verify checks that the code contains right character set, has the
+;; country specific length and has the correct check sum.
+;;
+(defun IBAN-verify (iban)
+  (flet ((validp (X) (and (IBAN-characters X)
+                          (IBAN-length X)
+                          (= 1 (mod (IBAN-to-integer X) 97)))))
+    (validp (remove #\Space iban))))