From c50ccbbd1a9b3780a367e0259d04e6c143197e3b Mon Sep 17 00:00:00 2001
From: "Sunrin SHIMURA (keen)" <3han5chou7@gmail.com>
Date: Thu, 23 Feb 2017 13:29:31 +0900
Subject: [PATCH] implement Error for IpNetworkError

---
 src/common.rs | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/common.rs b/src/common.rs
index 0465774..9df6f3c 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -1,4 +1,6 @@
 use std::net::Ipv4Addr;
+use std::fmt;
+use std::error::Error;
 
 /// Represents a bunch of errors that can occur while working with a `IpNetwork`
 #[derive(Debug,Clone,PartialEq,Eq)]
@@ -8,6 +10,29 @@ pub enum IpNetworkError {
     InvalidCidrFormat(String),
 }
 
+impl fmt::Display for IpNetworkError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use IpNetworkError::*;
+        match *self {
+            InvalidAddr(ref s) => write!(f, "invalid address: {}", s),
+            InvalidPrefix => write!(f, "invalid prifex"),
+            InvalidCidrFormat(ref s) => write!(f, "invalid cidr format: {}", s),
+        }
+    }
+}
+
+impl Error for IpNetworkError {
+    fn description(&self) -> &str {
+        use IpNetworkError::*;
+        match *self {
+            InvalidAddr(_) => "address is invalid",
+            InvalidPrefix => "prefix is invalid",
+            InvalidCidrFormat(_) => "cidr is invalid",
+        }
+
+    }
+}
+
 pub fn cidr_parts(cidr: &str) -> Result<(&str, &str), IpNetworkError> {
     let parts = cidr.split('/').collect::<Vec<&str>>();
     if parts.len() == 2 {