Use correct type size in unpack_type. Closes #30

Author: oschwald

HISTORY.rst

@@ -3,6 +3,10 @@
 History
 -------
 
+* Fix issue where incorrect size was used when unpacking some types with the
+  pure Python reader. Reported by Lee Symes. GitHub #30.
+
+
 1.3.0 (2017-03-13)
 ++++++++++++++++++
 

maxminddb/decoder.py

@@ -50,7 +50,7 @@ def _decode_packed_type(type_code, type_size, pad=False):
         def unpack_type(self, size, offset):
             if not pad:
                 self._verify_size(size, type_size)
-            new_offset = offset + type_size
+            new_offset = offset + size
             packed_bytes = self._buffer[offset:new_offset]
             if pad:
                 packed_bytes = packed_bytes.rjust(type_size, b'\x00')