September 2017 Update

Task/IBAN/Rust/iban.rust

@@ -0,0 +1,65 @@
+fn main() {
+    for iban in [
+        "",
+        "x",
+        "QQ82",
+        "QQ82W",
+        "GB82 TEST 1234 5698 7654 322",
+        "gb82 WEST 1234 5698 7654 32",
+        "GB82 WEST 1234 5698 7654 32",
+        "GB82 TEST 1234 5698 7654 32",
+        "GB81 WEST 1234 5698 7654 32",
+        "SA03 8000 0000 6080 1016 7519",
+        "CH93 0076 2011 6238 5295 7",
+    ].iter()
+    {
+        println!(
+            "'{}' is {}valid",
+            iban,
+            if validate_iban(iban) { "" } else { "NOT " }
+        );
+    }
+}
+
+fn validate_iban(iban: &str) -> bool {
+    let iso_len = [
+        ("AL", 28), ("AD", 24), ("AT", 20), ("AZ", 28), ("BE", 16), ("BH", 22),
+        ("BA", 20), ("BR", 29), ("BG", 22), ("HR", 21), ("CY", 28), ("CZ", 24),
+        ("DK", 18), ("DO", 28), ("EE", 20), ("FO", 18), ("FI", 18), ("FR", 27),
+        ("GE", 22), ("DE", 22), ("GI", 23), ("GL", 18), ("GT", 28), ("HU", 28),
+        ("IS", 26), ("IE", 22), ("IL", 23), ("IT", 27), ("KZ", 20), ("KW", 30),
+        ("LV", 21), ("LB", 28), ("LI", 21), ("LT", 20), ("LU", 20), ("MK", 19),
+        ("MT", 31), ("MR", 27), ("MU", 30), ("MC", 27), ("MD", 24), ("ME", 22),
+        ("NL", 18), ("NO", 15), ("PK", 24), ("PS", 29), ("PL", 28), ("PT", 25),
+        ("RO", 24), ("SM", 27), ("SA", 24), ("RS", 22), ("SK", 24), ("SI", 19),
+        ("ES", 24), ("SE", 24), ("CH", 21), ("TN", 24), ("TR", 26), ("AE", 23),
+        ("GB", 22), ("VG", 24), ("GR", 27), ("CR", 21),
+    ];
+    let trimmed_iban = iban.chars()
+        .filter(|&ch| ch != ' ')
+        .collect::<String>()
+        .to_uppercase();
+    if trimmed_iban.len() < 4 {
+        return false;
+    }
+    let prefix = &trimmed_iban[0..2];
+    if let Some(pair) = iso_len.iter().find(|&&(code, _)| code == prefix) {
+        if pair.1 != trimmed_iban.len() {
+            return false;
+        }
+    } else {
+        return false;
+    }
+    let reversed_iban = format!("{}{}", &trimmed_iban[4..], &trimmed_iban[0..4]);
+    let mut expanded_iban = String::new();
+    for ch in reversed_iban.chars() {
+        expanded_iban.push_str(&if ch.is_numeric() {
+            format!("{}", ch)
+        } else {
+            format!("{}", ch as u8 - 'A' as u8 + 10u8)
+        });
+    }
+    expanded_iban.bytes().fold(0, |acc, ch| {
+        (acc * 10 + ch as u32 - '0' as u32) % 97
+    }) == 1
+}