optimization for source handler

Author: robamu

src/cfdppy/handler/source.py

@@ -886,12 +886,7 @@ def _prepare_progressing_file_data_pdu(self) -> None:
         :return: True if a packet was prepared, False if PDU handling is done and the next steps
             in the Copy File procedure can be performed
         """
-        if self._params.fp.file_size < self._params.fp.segment_len:
-            read_len = self._params.fp.file_size
-        elif self._params.fp.progress + self._params.fp.segment_len > self._params.fp.file_size:
-            read_len = self._params.fp.file_size - self._params.fp.progress
-        else:
-            read_len = self._params.fp.segment_len
+        read_len = min(self._params.fp.segment_len, self._params.fp.file_size - self._params.fp.progress)
         self._prepare_file_data_pdu(self._params.fp.progress, read_len)
         self._params.fp.progress += read_len