Added needed traits to NetworkSize (#175)

* Add conversion and better equality traits to NetworkSize

* Add tests for NetworkSize conversion/equality

* impl Display for NetworkSize

src/size.rs

@@ -0,0 +1,161 @@
+use std::{cmp::Ordering, fmt::Display};
+
+use crate::error::NetworkSizeError;
+
+/// Represents a generic network size. For IPv4, the max size is a u32 and for IPv6, it is a u128
+#[derive(Debug, Clone, Copy, Hash)]
+pub enum NetworkSize {
+    V4(u32),
+    V6(u128),
+}
+use NetworkSize::*;
+
+// Conversions
+
+impl From<u128> for NetworkSize {
+    fn from(value: u128) -> Self {
+        V6(value)
+    }
+}
+
+impl From<u32> for NetworkSize {
+    fn from(value: u32) -> Self {
+        V4(value)
+    }
+}
+
+impl TryInto<u32> for NetworkSize {
+    type Error = NetworkSizeError;
+    fn try_into(self) -> Result<u32, Self::Error> {
+        match self {
+            V4(a) => Ok(a),
+            V6(_) => Err(NetworkSizeError::NetworkIsTooLarge),
+        }
+    }
+}
+
+impl Into<u128> for NetworkSize {
+    fn into(self) -> u128 {
+        match self {
+            V4(a) => a as u128,
+            V6(a) => a,
+        }
+    }
+}
+
+// Equality/comparisons
+
+impl PartialEq for NetworkSize {
+    fn eq(&self, other: &Self) -> bool {
+        let a: u128 = (*self).into();
+        let b: u128 = (*other).into();
+        a == b
+    }
+}
+
+impl Ord for NetworkSize {
+    fn cmp(&self, other: &Self) -> Ordering {
+        let a: u128 = (*self).into();
+        let b: u128 = (*other).into();
+        return a.cmp(&b);
+    }
+}
+
+impl PartialOrd for NetworkSize {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Eq for NetworkSize {}
+
+// Display
+
+impl Display for NetworkSize {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", Into::<u128>::into(*self))
+    }
+}
+
+// Tests
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_from_u128() {
+        let value: u128 = 100;
+        let ns = NetworkSize::from(value);
+        assert_eq!(ns, V6(100));
+    }
+
+    #[test]
+    fn test_from_u32() {
+        let value: u32 = 100;
+        let ns = NetworkSize::from(value);
+        assert_eq!(ns, V4(100));
+    }
+
+    #[test]
+    fn test_try_into_u32() {
+        let value: u32 = 100;
+        let ns = V4(value);
+        let result: Result<u32, _> = ns.try_into();
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), value);
+    }
+
+    #[test]
+    fn test_try_into_u32_error() {
+        let value: u128 = u32::MAX as u128 + 1;
+        let ns = V6(value);
+        let result: Result<u32, _> = ns.try_into();
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_into_u128() {
+        let value: u32 = 100;
+        let ns = V4(value);
+        let result: u128 = ns.into();
+        assert_eq!(result, value as u128);
+    }
+
+    #[test]
+    fn test_eq() {
+        let ns1 = V4(100);
+        let ns2 = V4(100);
+        assert_eq!(ns1, ns2);
+
+        let ns1 = V6(100);
+        let ns2 = V6(100);
+        assert_eq!(ns1, ns2);
+
+        let ns1 = V4(100);
+        let ns2 = V6(100);
+        assert_eq!(ns1, ns2);
+    }
+
+    #[test]
+    fn test_cmp() {
+        let ns1 = V4(100);
+        let ns2 = V4(200);
+        assert!(ns1 < ns2);
+
+        let ns1 = V6(200);
+        let ns2 = V6(100);
+        assert!(ns1 > ns2);
+
+        let ns1 = V4(100);
+        let ns2 = V6(200);
+        assert!(ns1 < ns2);
+    }
+
+    #[test]
+    fn test_display() {
+        let ns1 = V4(u32::MAX);
+        let ns2 = V6(ns1.into());
+        assert_eq!(ns1.to_string(), ns2.to_string());
+    }
+}