one more refactor

dpkt/compat.py

@@ -1,6 +1,6 @@
 from __future__ import absolute_import
 
-import struct
+from struct import pack, unpack
 import sys
 
 if sys.version_info < (3,):
@@ -40,9 +40,8 @@ def iteritems(d, **kw):
     intround = round
 
 
-def ntole(fmt, v):
-    """convert a 2-byte word (fmt='H') or a 4-byte integer (fmt='I')
-    from the network byte order (big endian) to little endian;
+def ntole(v):
+    """convert a 2-byte word from the network byte order (big endian) to little endian;
     replaces socket.ntohs() to work on both little and big endian architectures
     """
-    return struct.unpack('<' + fmt, struct.pack('!' + fmt, v))[0]
+    return unpack('<H', pack('!H', v))[0]

dpkt/dpkt.py

@@ -208,7 +208,7 @@ def in_cksum_add(s, buf):
 def in_cksum_done(s):
     s = (s >> 16) + (s & 0xffff)
     s += (s >> 16)
-    return ntole('H', ~s & 0xffff)
+    return ntole(~s & 0xffff)
 
 
 def in_cksum(buf):

dpkt/ieee80211.py

@@ -363,7 +363,7 @@ def unpack(self, buf):
         if self.type == MGMT_TYPE:
             self.unpack_ies(field.data)
             if self.subtype in FRAMES_WITH_CAPABILITY:
-                self.capability = self.Capability(ntole('H', field.capability))
+                self.capability = self.Capability(ntole(field.capability))
 
         if self.type == DATA_TYPE and self.subtype == D_QOS_DATA:
             self.qos_data = self.QoS_Data(field.data)
@@ -422,7 +422,7 @@ def tid(self, val):
         def unpack(self, buf):
             dpkt.Packet.unpack(self, buf)
             self.data = buf[self.__hdr_len__:]
-            self.ctl = ntole('H', self.ctl)
+            self.ctl = ntole(self.ctl)
 
             if self.compressed:
                 self.bmp = struct.unpack('8s', self.data[0:_COMPRESSED_BMP_LENGTH])[0]

dpkt/radiotap.py

@@ -233,7 +233,7 @@ def ext_present(self, val):
 
     def unpack(self, buf):
         dpkt.Packet.unpack(self, buf)
-        self.data = buf[ntole('H', self.length):]
+        self.data = buf[ntole(self.length):]
 
         self.fields = []
         buf = buf[self.__hdr_len__:]