seek() using relative offsets, not tell()

Author: arekbulski

kaitaistruct.py

@@ -1,7 +1,8 @@
 import itertools
 import sys
 import struct
-from io import BytesIO  # noqa
+import io
+from io import BytesIO, SEEK_CUR, SEEK_END  # noqa
 
 PY2 = sys.version_info[0] == 2
 
@@ -71,7 +72,7 @@ def is_eof(self):
         if t == b'':
             return True
         else:
-            io.seek(io.tell() - 1)
+            io.seek(-1, SEEK_CUR)
             return False
 
     def seek(self, n):
@@ -88,7 +89,7 @@ def size(self):
         # Remember our current position
         cur_pos = io.tell()
         # Seek to the end of the File object
-        io.seek(0, 2)
+        io.seek(0, SEEK_END)
         # Remember position, which is equal to the full length
         full_size = io.tell()
         # Seek back to the current position
@@ -287,7 +288,7 @@ def read_bytes_term(self, term, include_term, consume_term, eos_error):
                 if include_term:
                     r += c
                 if not consume_term:
-                    self._io.seek(self._io.tell() - 1)
+                    self._io.seek(-1, SEEK_CUR)
                 return r
             else:
                 r += c