The Software IP Detective’s Handbook: Measurement, Comparison, and Infringement Detection

18. Theory

Many experts believe that decompiling object code back into source code is required before an accurate determination of copying can take place. However, consider the original source code for the small routine in Listing 18.1 and compare it to the decompiled version of that routine in Listing 18.2. The comments in Listing 18.1 of course are gone, but worse, the decompiler has inserted its own comments on lines 1 through 4, 6, and 16 through 19. This is worse because for purposes of finding similarity, the decompiler itself creates correlation between two sets of unrelated code because of the comments it inserts. Note that the strings are unchanged, as we would expect, and the function names are unchanged, though variables have been ...