fix for chunk number calculation when unaligned - thanks to Daniel Lundin for the patch

Author: Mike Dirolf

doc/contributors.rst

@@ -18,3 +18,4 @@ The following is a list of people who have contributed to
 - Joshua Roesslein (joshthecoder)
 - Gregg Lind (gregglind)
 - Michael Schurter (schmichael)
+- Daniel Lundin

gridfs/grid_file.py

@@ -306,7 +306,7 @@ def read(self, size=-1):
  size = remainder
 
  bytes = self.__buffer
- chunk_number = math.floor(self.__position / self.__chunk_size)
+ chunk_number = (len(bytes) + self.__position) / self.__chunk_size
 
  while len(bytes) < size:
  chunk = self.__collection.chunks.find_one({"files_id": self.__id, "n": chunk_number})

test/test_grid_file.py

@@ -406,5 +406,26 @@ def test_spec_with_id(self):
  file = GridFile({"_id": "foobar", "filename": "foobar"}, self.db, "w")
  file.close()
 
+ def test_read_chunks_unaligned_buffer_size(self):
+ self.db.fs.files.remove({})
+ self.db.fs.chunks.remove({})
+
+ in_data = "This is a text that doesn't quite fit in a single 16-byte chunk."
+ f = GridFile({"filename":"test", "chunkSize":16}, self.db, "w")
+ f.write(in_data)
+ f.close()
+
+ f = GridFile({"filename":"test"}, self.db)
+ out_data = ''
+ while 1:
+ s = f.read(13)
+ if not s:
+ break
+ out_data += s
+ f.close()
+
+ self.assertEqual(in_data, out_data)
+
+
 if __name__ == "__main__":
  unittest.main()