You can pack bytes into a structure in prolog succintly enough too open('test.tar',read,TarFile) HSizes = [100,8,8,8,12,12,8,1,100,6,2,32,32,8,8,155,12],

You can pack bytes into a structure in prolog succintly enough too open('test.tar',read,TarFile) HSizes = [100,8,8,8,12,12,8,1,100,6,2,32,32,8,8,155,12], maplist(length,HBytes,HSizes), append(HBytes,~read_bytes(TarFile,512)), HBytes is now a list of lists of your bytes, do with them as you please, we can even name them if we want HFields = [ filename, filemode, ownerid, groupid, filesize , modificationtime, checksum, typeflag, linkedfilename , ownerusername, ownergroupname, devicemajornumber , deviceminornumber, filenameprefix, padding], keys_and_values(HFields,HBytes,Header), you could push it off into a predicate and it'd even more or less work relationally and it'd probably be faster than the DCG... but it wouldn't be interesting. And like they said https://news.ycombinator.com/item?id=34431450 https://news.ycombinator.com/item?id=34431450