Extracting abstract data types from C programs: A case study

The results of a case study in identifying and extracting reusable abstract data types from C programs are presented. Reuse re-engineering processes already established in the RE/sup 2/ project are applied. The method for identifying abstract data types uses an interconnection graph called a variable-reference graph, and coincidental and spurious connections within the graph are resolved using a statistical technique. A prototype tool is described which demonstrates the feasibility of the method. The tool is used to analyze a C program, and a number of abstract data types are identified and used in the maintenance of the original program. The validity of the method is assessed by a simple manual analysis of the source code. The resulting reusable components are then specified using the formal notation Z.<>