+ @classmethod
+ def parse_format(cls, txt, is_a_dsc=False, field='files'):
+ format = re_verwithext.search(txt)
+
+ if format is None:
+ raise UnknownFormatError, txt
+
+ format = format.groups()
+
+ if format[1] is None:
+ format = int(float(format[0])), 0, format[2]
+ else:
+ format = int(format[0]), int(format[1]), format[2]
+
+ if format[2] is None:
+ format = format[:2]
+
+ if is_a_dsc:
+ if format != (1,0) and \
+ format != (3,0,"quilt") and format != (3,0,"native"):
+ raise UnknownFormatError, txt
+ else:
+ if (format < (1,5) or format > (1,8)):
+ raise UnknownFormatError, txt
+ if field != "files" and format < (1,8):
+ raise UnknownFormatError, txt
+
+ return format
+