Add support for badly terminated files (dtcooper#114)

Author: scott-phillips-ah

fitparse/base.py

@@ -80,6 +80,7 @@ def _read_struct(self, fmt, endian='<', data=None, always_tuple=False):
 
     def _read_and_assert_crc(self, allow_zero=False):
         # CRC Calculation is little endian from SDK
+        # TODO - How to handle the case of unterminated file? Error out and have user retry with check_crc=false?
         crc_computed, crc_read = self._crc.value, self._read_struct(Crc.FMT)
         if not self.check_crc:
             return
@@ -132,7 +133,8 @@ def _parse_file_header(self):
     def _parse_message(self):
         # When done, calculate the CRC and return None
         if self._bytes_left <= 0:
-            if not self._complete:
+            # Don't assert CRC if requested not
+            if not self._complete and self.check_crc:
                 self._read_and_assert_crc()
 
             if self._file.tell() >= self._filesize:
@@ -245,9 +247,14 @@ def _parse_raw_values_from_data_message(self, def_mesg):
             struct_fmt = str(int(field_def.size / base_type.size)) + base_type.fmt
 
             # Extract the raw value, ask for a tuple if it's a byte type
-            raw_value = self._read_struct(
-                struct_fmt, endian=def_mesg.endian, always_tuple=is_byte,
-            )
+            try:
+                raw_value = self._read_struct(
+                    struct_fmt, endian=def_mesg.endian, always_tuple=is_byte,
+                )
+            except FitEOFError:
+                # file was suddenly terminated, usually due to
+                print("File was terminated unexpectedly, some data will not be loaded.")
+                break
 
             # If the field returns with a tuple of values it's definitely an
             # oddball, but we'll parse it on a per-value basis it.

scripts/fitdump

@@ -99,7 +99,7 @@ def main(args=None):
     fitfile = fitparse.FitFile(
         options.infile,
         data_processor=fitparse.StandardUnitsDataProcessor(),
-        check_crc = not(options.ignore_crc),
+        check_crc=not(options.ignore_crc),
     )
     records = fitfile.get_messages(
         name=options.name,

tests/files/nick.fit

@@ -420,6 +420,10 @@ def test_mismatched_field_size(self):
             assert all("falling back to byte encoding" in str(x) for x in w)
         self.assertEqual(len(f.messages), 11293)
 
+    def test_unterminated_file(self):
+        f = FitFile(testfile('nick.fit'), check_crc=False)
+        f.parse()
+
     # TODO:
     #  * Test Processors:
     #    - process_type_<>, process_field_<>, process_units_<>, process_message_<>