Data commit

Task/IBAN/UNIX-Shell/iban.sh

@@ -0,0 +1,34 @@
+declare -A base36=(
+    [A]=10 [B]=11 [C]=12 [D]=13 [E]=14 [F]=15 [G]=16 [H]=17 [I]=18
+    [J]=19 [K]=20 [L]=21 [M]=22 [N]=23 [O]=24 [P]=25 [Q]=26 [R]=27
+    [S]=28 [T]=29 [U]=30 [V]=31 [W]=32 [X]=33 [Y]=34 [Z]=35
+)
+
+function is_iban {
+    local -u acct=${1//[^[:alnum:]]/}
+    acct=${acct:4}${acct:0:4}
+    local i char digits=""
+    for ((i=0; i<${#acct}; i++)); do
+        char=${acct:i:1}
+        digits+=${base36[$char]:-$char}
+    done
+    local mod=$(mod97 $digits)
+    (( mod == 1 ))
+}
+
+function mod97 {
+    local D=$1
+    N=${D:0:9}
+    D=${D:9}
+    while [[ -n $D ]]; do
+        mod=$(( N % 97 ))
+        N=$(printf "%02d%s" $mod ${D:0:7})
+        D=${D:7}
+    done
+    echo $(( N % 97 ))
+}
+
+for test in "GB82 WEST 1234 5698 7654 32" "GB42 WEST 1234 5698 7654 32"; do
+    printf "%s : " "$test"
+    is_iban "$test" && echo yes || echo no
+done