Several PureCN output files have "C" columns containing estimated copy number.  Is the data in these columns adjusted for purity?  That is, do they reflect the copy number of the tumor tissue and not the normal tissue that is mixed in with it?  If not, am I correct to think that the adjustment would be:

Adjusted_C = (Unadjusted_C - 2*(1-purity)) / purity

Yes, these are already  adjusted. No need for manual calculations.