Unpacker: add tell() (#227)

1 files changed, 5 insertions, 0 deletions

diff --git a/msgpack/fallback.py b/msgpack/fallback.py
index d2eb9f4..508fd06 100644
--- a/msgpack/fallback.py
+++ b/msgpack/fallback.py
@@ -244,6 +244,7 @@ class Unpacker(object):
         self._max_array_len = max_array_len
         self._max_map_len = max_map_len
         self._max_ext_len = max_ext_len
+        self._stream_offset = 0
 
         if list_hook is not None and not callable(list_hook):
             raise TypeError('`list_hook` is not callable')
@@ -266,6 +267,7 @@ class Unpacker(object):
 
     def _consume(self):
         """ Gets rid of the used parts of the buffer. """
+        self._stream_offset += self._buff_i - self._buf_checkpoint
         self._buf_checkpoint = self._buff_i
 
     def _got_extradata(self):
@@ -629,6 +631,9 @@ class Unpacker(object):
         self._consume()
         return ret
 
+    def tell(self):
+        return self._stream_offset
+
 
 class Packer(object):
     """