Data commit

Task/Canonicalize-CIDR/Rust/canonicalize-cidr.rust

@@ -0,0 +1,39 @@
+use std::net::Ipv4Addr;
+
+fn canonical_cidr(cidr: &str) -> Result<String, &str> {
+    let mut split = cidr.splitn(2, '/');
+    if let (Some(addr), Some(mask)) = (split.next(), split.next()) {
+        let addr = addr.parse::<Ipv4Addr>().map(u32::from).map_err(|_| cidr)?;
+        let mask = mask.parse::<u8>().map_err(|_| cidr)?;
+        let bitmask = 0xff_ff_ff_ffu32 << (32 - mask);
+        let addr = Ipv4Addr::from(addr & bitmask);
+        Ok(format!("{}/{}", addr, mask))
+    } else {
+        Err(cidr)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    #[test]
+    fn valid() {
+        [
+            ("87.70.141.1/22", "87.70.140.0/22"),
+            ("36.18.154.103/12", "36.16.0.0/12"),
+            ("62.62.197.11/29", "62.62.197.8/29"),
+            ("67.137.119.181/4", "64.0.0.0/4"),
+            ("161.214.74.21/24", "161.214.74.0/24"),
+            ("184.232.176.184/18", "184.232.128.0/18"),
+        ]
+        .iter()
+        .cloned()
+        .for_each(|(input, expected)| {
+            assert_eq!(expected, super::canonical_cidr(input).unwrap());
+        });
+    }
+}
+
+fn main() {
+    println!("{}", canonical_cidr("127.1.2.3/24").unwrap());
+}