putHeader :: Entry -> ByteString
putHeader entry =
     BS.Char8.pack $ take 148 block
  ++ putOct 7 checksum
  ++ ' ' : drop 156 block
  where
    block    = putHeaderNoChkSum entry
    checksum = foldl' (\x y -> x + ord y) 0 block
putHeader :: Entry -> ByteString
putHeader entry =
     BS.Char8.pack $ take 148 block
  ++ putOct 7 checksum
  ++ ' ' : drop 156 block
  where
    block    = putHeaderNoChkSum entry
    checksum = foldl' (\x y -> x + ord y) 0 block
putHeader entry =
     BS.Char8.pack $ take 148 block
  ++ putOct 7 checksum
  ++ ' ' : drop 156 block
  where
    block    = putHeaderNoChkSum entry
    checksum = foldl' (\x y -> x + ord y) 0 block