Issue 94: Make IPSet.__contains__ faster

2 files changed, 23 insertions, 4 deletions

diff --git a/CHANGELOG b/CHANGELOG
index dd6be38..ec182ab 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,22 @@
 ---------------
+Release: 0.7.15
+---------------
+Date: ?????????
+
+^^^^^^^^^^^^^^^^^^^^
+Changes since 0.7.14
+^^^^^^^^^^^^^^^^^^^^
+
+* Fix slowness in IPSet.__contains__. Thanks to novas0x2a for noticing.
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Specific bug fixes addressed in this release
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+FIXED Issue 94: https://github.com/drkjam/netaddr/issues/94
+    - IPSet.__contains__ is about 40 times slower than the equivalent IPRange
+
+---------------
 Release: 0.7.14
 ---------------
 Date: 31st Mar 2015
diff --git a/netaddr/ip/sets.py b/netaddr/ip/sets.py
index 204ffd2..70f44cf 100644
--- a/netaddr/ip/sets.py
+++ b/netaddr/ip/sets.py
@@ -231,15 +231,16 @@ class IPSet(object):
 
         :return: ``True`` if IP address or subnet is a member of this IP set.
         """
-        ip = IPNetwork(ip)
         # Iterating over self._cidrs is an O(n) operation: 1000 items in
         # self._cidrs would mean 1000 loops. Iterating over all possible
         # supernets loops at most 32 times for IPv4 or 128 times for IPv6,
         # no matter how many CIDRs this object contains.
-        if ip in self._cidrs:
+        supernet = IPNetwork(ip)
+        if supernet in self._cidrs:
             return True
-        for cidr in ip.supernet():
-            if cidr in self._cidrs:
+        while supernet._prefixlen:
+            supernet._prefixlen -= 1
+            if supernet in self._cidrs:
                 return True
         return False