file: simplify disk_file_size function
file: simplify disk_file_size function

Limecraft/ebu-libmxf,stuarthicks/libmxf,ebu/ebu-libmxf,ebu/ebu-libmxf,stuarthicks/libmxf,stuarthicks/libmxf,stuarthicks/libmxf,Limecraft/ebu-libmxf,ebu/ebu-libmxf,ebu/ebu-libmxf,Limecraft/ebu-libmxf