From 1b06452e889638d8f5bda66ebeeb6b86fa82f320 Mon Sep 17 00:00:00 2001
From: Abhishek Chanda <abhishek.becs@gmail.com>
Date: Sat, 2 Feb 2019 23:57:25 +0000
Subject: [PATCH] Optimise contains for IPv4

---
 src/ipv4.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/ipv4.rs b/src/ipv4.rs
index 67f49d7..ec4fa27 100644
--- a/src/ipv4.rs
+++ b/src/ipv4.rs
@@ -131,8 +131,8 @@ impl Ipv4Network {
     /// assert!(!net.contains(Ipv4Addr::new(127, 0, 1, 70)));
     /// ```
     pub fn contains(&self, ip: Ipv4Addr) -> bool {
-        let net = u32::from(self.network());
-        let mask = u32::from(self.mask());
+        let mask = !(0xffff_ffff as u64 >> self.prefix) as u32;
+        let net = u32::from(self.addr) & mask;
         (u32::from(ip) & mask) == net
     }