(ZZIP_FILE * fp) ;
zzip_tell function will
tell(2) the current position in a real/zipped file
It will return the current offset within the real/zipped file, measured in uncompressed bytes for the zipped-file case.
If the file-handle is wrapping a stat'able file then it will actually just
perform a normal
tell(2)-call, otherwise the offset is
calculated from the amount of data left and the total uncompressed