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Refactoring :qrref module
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@jlangch
jlangch committed Oct 9, 2024
1 parent 8153183 commit aeec09c
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Showing 2 changed files with 93 additions and 72 deletions.
5 changes: 3 additions & 2 deletions ...ain/java/com/github/jlangch/venice/impl/docgen/cheatsheet/modules/ModuleQrRefSection.java
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Original file line number Diff line number Diff line change
Expand Up @@ -45,9 +45,10 @@ public DocSection section() {

final DocSection main = new DocSection("QR Ref", id());
all.addSection(main);
main.addItem(diBuilder.getDocItem("qrref/qr-ref", true));
main.addItem(diBuilder.getDocItem("qrref/parse", true));
main.addItem(diBuilder.getDocItem("qrref/create", true));
main.addItem(diBuilder.getDocItem("qrref/format", true));
main.addItem(diBuilder.getDocItem("qrref/valid?", true));
main.addItem(diBuilder.getDocItem("qrref/checksum", true));

return section;
}
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160 changes: 90 additions & 70 deletions src/main/resources/com/github/jlangch/venice/qrref.venice
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,6 @@
(ns qrref)


(def- qr-ref-len 27) ;; number of QR reference digits, checksum digit included

(def- qr-ref-raw-len 26) ;; number of QR reference digits, checksum digit excluded

(def- checksum-table [0, 9, 4, 6, 8, 2, 7, 1, 3, 5])


Expand All @@ -38,13 +34,6 @@
(defn- digit->char [c] (char (+ c (long #\0)))) ;; 2 -> #\2


(defn- remove-leading-zeroes [s]
(loop [s s]
(if (and (> (count s) 1) (str/starts-with? s "0"))
(recur (str/rest s))
s)))


(defn- remove-whitespaces [s]
(apply str (filter #(not (str/whitespace? %)) (seq s))))

Expand All @@ -53,67 +42,63 @@
(match? s #"[0-9]+"))


(defn- qr-ref-raw [ref]
(let [padding-zeros (- qr-ref-raw-len (count ref))]
(defn- pad-with-leading-zeroes [ref]
(let [padding-zeros (- 26 (count ref))]
(if (neg? padding-zeros)
(throw (ex :VncException "The QR-Reference ref number is too long!"))
(str (str/repeat "0" padding-zeros) ref))))


(defn checksum [s]
^{ :arglists '("(checksum ref)")
(defn
^{ :arglists '("(create ref-raw)")
:doc """
Calculates the checksum for a raw reference. The reference may
contain spaces.
"""
:examples '(
"""
(do
(load-module :qrref ['qrref :as 'qr])
(qr/checksum "230 55361 34663 9301")
(qr/checksum "23055361346639301")
(qr/checksum "00 00000 00230 55361 34663 9301")
(qr/checksum "00000000023055361346639301"))
""" )
:see-also '("qrref/create", "qrref/valid?", "qrref/format") }
Creates a QR reference according to the Swiss payment standards.

(let [s (remove-whitespaces s)]
(if-not (numeric? s)
(throw (ex :VncException "Invalid character in reference (digits allowed only)"))
(loop [carry 0, digits (seq s)]
(if (empty? digits)
(mod (- 10 carry) 10)
(let [digit (digit->long (first digits))
carry (get checksum-table (mod (+ carry digit) 10))]
(recur carry (rest digits))))))))
A QR reference has 27 digits. The raw reference plus a checksum digit
as the last digit.

The raw reference passed must not have more than 26 digits. With less
than 26 digits leading '0' will be used to fill up to 26 digits.

Raw reference: "23055361346639301"

(defn valid? [ref]
^{ :arglists '("(valid? ref)")
:doc """
Returns true if ref is a valid QR reference else false.
The reference may contain spaces.
QR reference: "000000000230553613466393013"

The QR reference can be formatted to "00 00000 00230 55361 34663 93013"
using:

```
(qrref/format "000000000230553613466393013")
```

[Swiss Payment Standards / de](https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-de.pdf)

[Swiss Payment Standards / en](https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-en.pdf)
"""
:examples '(
"""
(do
(load-module :qrref ['qrref :as 'qr])
(qr/valid? "000000000230553613466393013")
(qr/valid? "00 00000 00230 55361 34663 93013"))
(qr/create "1234")
(qr/create "23055361346639301"))
""" )
:see-also '("qrref/create", "qrref/format", "qrref/checksum") }
:see-also '("qrref/valid?", "qrref/format", "qrref/checksum") }

(let [r (remove-whitespaces ref)]
(if-not (numeric? r)
false
(if-not (== qr-ref-len (count r))
false
(== 0 (checksum r))))))
create [ref-raw]

(let [r (remove-whitespaces ref-raw)]
(when-not (numeric? r)
(throw (ex :VncException "Invalid character in reference (digits allowed only)")))
(when (> (count r) 26)
(throw (ex :VncException "A raw QR reference must not have more than 26 digits")))

(let [padded (pad-with-leading-zeroes r)
check-digit (digit->char (checksum padded))]
(str padded check-digit))))


(defn
^{ :arglists '("(format s)")
^{ :arglists '("(format ref)")
:doc "Format a QR reference."
:examples '(
"""
Expand All @@ -123,39 +108,74 @@
""" )
:see-also '("qrref/create", "qrref/valid?", "qrref/checksum") }

format [s]
format [ref]

(->> (seq s)
(->> (seq ref)
(reverse)
(partition-all 5)
(map #(apply str (reverse %)))
(reverse)
(str/join " ")))

(defn
^{ :arglists '("(create ref)")

(defn
^{ :arglists '("(valid? ref)")
:doc """
Creates a QR reference according to the Swiss payment standards.
Returns true if ref is a valid QR reference else false.
The reference may contain spaces.

[Swiss Payment Standards / de](https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-de.pdf)
A valid QR reference must have 27 digits and the checksum must be
correct. The last digit is the checksum digits for the first 26 digits.
"""
:examples '(
"""
(do
(load-module :qrref ['qrref :as 'qr])
(qr/valid? "000000000230553613466393013")
(qr/valid? "00 00000 00230 55361 34663 93013"))
""" )
:see-also '("qrref/create", "qrref/format", "qrref/checksum") }

[Swiss Payment Standards / en](https://www.paymentstandards.ch/dam/downloads/ig-qr-bill-en.pdf)
valid? [ref]

(let [r (remove-whitespaces ref)]
(if (and (numeric? r) (== 27 (count r)))
(== 0 (checksum r))
false)))


(defn
^{ :arglists '("(checksum ref)")
:doc """
Computes the checksum for a raw reference.

The passed ref my be a raw QR reference or a QR reference with a
checksum digit. It may contain spaces.

Returns the computed checksum digit 0..9.

If the passed ref is a QR reference with a correct checksum digit the
computed checksum digit will always be 0. This fact is used for QR
reference validation!
"""
:examples '(
"""
(do
(load-module :qrref ['qrref :as 'qr])
(qr/create "1234")
(qr/create "23055361346639301"))
(qr/checksum "230 55361 34663 9301")
(qr/checksum "23055361346639301")
(qr/checksum "00 00000 00230 55361 34663 9301")
(qr/checksum "00000000023055361346639301"))
""" )
:see-also '("qrref/valid?", "qrref/format", "qrref/checksum") }
:see-also '("qrref/create", "qrref/valid?", "qrref/format") }

create[ref-raw]
checksum [ref]

(let [r (remove-whitespaces ref-raw)]
(if-not (match? r #"[0-9]+")
(throw (ex :VncException "Invalid character in reference (digits allowed only)"))
(if (> (count r) 26)
(throw (ex :VncException "Reference number is longer than 26 digits!"))
(let [r (qr-ref-raw r)]
(str r (digit->char (checksum r))))))))
(let [r (remove-whitespaces ref)]
(when-not (numeric? r)
(throw (ex :VncException "Invalid character in reference (digits allowed only)")))

(let [carry (reduce (fn [carry digit] (get checksum-table (mod (+ carry digit) 10)))
0
(map digit->long (seq r)))]
(mod (- 10 carry) 10))))

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