Remove unused interleaved reading code (#234)

nptdms/tdms_segment.py

@@ -365,17 +365,13 @@ class InterleavedDataReader(BaseDataReader):
     def read_data_chunks(self, file, data_objects, num_chunks):
         """ Read multiple data chunks at once
         """
-        # If all data types are sized and all the lengths are
-        # the same, then we can read all data at once with numpy,
-        # which is much faster
-        all_sized = all(
-            o.data_type.size is not None for o in data_objects)
+        if len(data_objects) == 0:
+            return []
         same_length = (len(
             set((o.number_values for o in data_objects))) == 1)
-        if all_sized and same_length:
-            return [self._read_interleaved_sized(file, data_objects, num_chunks)]
-        else:
-            return [self._read_interleaved(file, data_objects, num_chunks)]
+        if not same_length:
+            raise ValueError("Cannot read interleaved data with different chunk sizes")
+        return [self._read_interleaved_chunks(file, data_objects, num_chunks)]
 
     def read_channel_data_chunks(self, file, data_objects, channel_path, chunk_offset, stop_chunk):
         """ Read multiple data chunks for a single channel at once
@@ -389,7 +385,7 @@ def _read_data_chunk(self, file, data_objects, chunk_index):
         """
         raise NotImplementedError("Reading a single chunk is not implemented for interleaved data")
 
-    def _read_interleaved_sized(self, file, data_objects, num_chunks):
+    def _read_interleaved_chunks(self, file, data_objects, num_chunks):
         """Read interleaved data where all channels have a sized data type and the same length
         """
         total_data_width = sum(o.data_type.size for o in data_objects)
@@ -416,25 +412,6 @@ def _read_interleaved_sized(self, file, data_objects, num_chunks):
 
         return RawDataChunk.channel_data(channel_data)
 
-    def _read_interleaved(self, file, data_objects, num_chunks):
-        """Read interleaved data that doesn't have a numpy type"""
-
-        log.debug("Reading interleaved data point by point")
-        object_data = {}
-        points_added = {}
-        for obj in data_objects:
-            object_data[obj.path] = obj.new_segment_data()
-            points_added[obj.path] = 0
-        while any([points_added[o.path] < (o.number_values * num_chunks)
-                   for o in data_objects]):
-            for obj in data_objects:
-                if points_added[obj.path] < obj.number_values:
-                    object_data[obj.path][points_added[obj.path]] = (
-                        obj.read_value(file, self.endianness))
-                    points_added[obj.path] += 1
-
-        return RawDataChunk.channel_data(object_data)
-
 
 class ContiguousDataReader(BaseDataReader):
     """ Reads data in a TDMS segment with contiguous (non-interleaved) data
@@ -516,14 +493,6 @@ def read_raw_data_index(self, f, raw_data_index_header, endianness):
         else:
             self.data_size = self.number_values * self.data_type.size
 
-    def read_value(self, file, endianness):
-        """Read a single value from the given file"""
-
-        if self.data_type.nptype is not None:
-            dtype = self.data_type.nptype.newbyteorder(endianness)
-            return fromfile(file, dtype=dtype, count=1)[0]
-        return self.data_type.read(file, endianness)
-
     def read_values(self, file, number_values, endianness):
         """Read all values for this object from a contiguous segment"""
 

nptdms/test/test_tdms_file.py

@@ -863,3 +863,55 @@ def test_multiple_close_after_open():
         tdms_data.close()
     finally:
         os.remove(temp_file.name)
+
+
+def test_interleaved_segment_different_length():
+    test_file = GeneratedFile()
+    test_file.add_segment(
+        ("kTocMetaData", "kTocRawData", "kTocNewObjList", "kTocInterleavedData"),
+        segment_objects_metadata(
+            channel_metadata("/'group'/'channel1'", 3, 3),
+            channel_metadata("/'group'/'channel2'", 3, 2),
+        ),
+        "01 00 00 00" "02 00 00 00"
+        "01 00 00 00" "02 00 00 00"
+        "01 00 00 00"
+    )
+
+    with pytest.raises(ValueError) as exc_info:
+        _ = test_file.load()
+    assert str(exc_info.value) == "Cannot read interleaved data with different chunk sizes"
+
+
+def test_interleaved_segment_unsized():
+    test_file = GeneratedFile()
+    string_channel_metadata = (
+        # Length of the object path
+        "18 00 00 00" +
+        string_hexlify("/'group'/'StringChannel'") +
+        # Length of index information
+        "1C 00 00 00"
+        # Raw data data type
+        "20 00 00 00"
+        # Dimension
+        "01 00 00 00"
+        # Number of raw data values
+        "02 00 00 00"
+        "00 00 00 00"
+        # Number of bytes in data
+        "19 00 00 00"
+        "00 00 00 00"
+        # Number of properties (0)
+        "00 00 00 00")
+    test_file.add_segment(
+        ("kTocMetaData", "kTocRawData", "kTocNewObjList", "kTocInterleavedData"),
+        segment_objects_metadata(
+            channel_metadata("/'group'/'channel1'", 3, 2),
+            string_channel_metadata,
+        ),
+        "01 00 00 00" "02 00 00 00"
+        "01 00 00 00" "02 00 00 00"
+    )
+
+    with pytest.raises(TypeError):
+        _ = test_file.load()