1 files changed, 42 insertions, 0 deletions
diff --git a/src/config/port.rs b/src/config/port.rs
new file mode 100644
index 0000000..01e305b
--- /dev/null
+++ b/src/config/port.rs
@@ -0,0 +1,42 @@
+use std::ops::RangeInclusive;
+
+const PORT_RANGE: RangeInclusive<usize> = 1..=65535;
+
+pub fn port_in_range(s: &str) -> Result<u16, String> {
+    let port = s
+        .parse()
+        .map_err(|_| format!("{s} is not a valid port number"))?;
+
+    if PORT_RANGE.contains(&port) {
+        Ok(port as u16)
+    } else {
+        Err(format!(
+            "port not in range {}-{}",
+            PORT_RANGE.start(),
+            PORT_RANGE.end()
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use rand::Rng;
+
+    use super::*;
+
+    #[test]
+    fn in_port_range() {
+        let mut rng = rand::rng();
+        let num = rng.random_range(PORT_RANGE);
+
+        assert!(port_in_range(&num.to_string()).is_ok());
+    }
+
+    #[test]
+    fn outside_port_range() {
+        let mut rng = rand::rng();
+        let num = rng.random_range((65535 + 1)..=usize::MAX);
+
+        assert!(port_in_range(&num.to_string()).is_err());
+    }
+}