src/Maskbits.hs

   1 module Maskbits
   2 ( Maskbits(..),
   3   maskbits_from_string
   4 ) where
   5
   6 -- A type representing the number of bits in a CIDR netmask.
   7 data Maskbits = None
   8               | Zero
   9               | One
  10               | Two
  11               | Three
  12               | Four
  13               | Five
  14               | Six
  15               | Seven
  16               | Eight
  17               | Nine
  18               | Ten
  19               | Eleven
  20               | Twelve
  21               | Thirteen
  22               | Fourteen
  23               | Fifteen
  24               | Sixteen
  25               | Seventeen
  26               | Eighteen
  27               | Nineteen
  28               | Twenty
  29               | TwentyOne
  30               | TwentyTwo
  31               | TwentyThree
  32               | TwentyFour
  33               | TwentyFive
  34               | TwentySix
  35               | TwentySeven
  36               | TwentyEight
  37               | TwentyNine
  38               | Thirty
  39               | ThirtyOne
  40               | ThirtyTwo
  41               deriving (Eq, Ord, Show)
  42
  43
  44 -- There are only 32 bits in an IPv4 address, so there
  45 -- can't be more bits than that in the mask.
  46 maskbits_from_int :: Int -> Maskbits
  47 maskbits_from_int 0  = Zero
  48 maskbits_from_int 1  = One
  49 maskbits_from_int 2  = Two
  50 maskbits_from_int 3  = Three
  51 maskbits_from_int 4  = Four
  52 maskbits_from_int 5  = Five
  53 maskbits_from_int 6  = Six
  54 maskbits_from_int 7  = Seven
  55 maskbits_from_int 8  = Eight
  56 maskbits_from_int 9  = Nine
  57 maskbits_from_int 10 = Ten
  58 maskbits_from_int 11 = Eleven
  59 maskbits_from_int 12 = Twelve
  60 maskbits_from_int 13 = Thirteen
  61 maskbits_from_int 14 = Fourteen
  62 maskbits_from_int 15 = Fifteen
  63 maskbits_from_int 16 = Sixteen
  64 maskbits_from_int 17 = Seventeen
  65 maskbits_from_int 18 = Eighteen
  66 maskbits_from_int 19 = Nineteen
  67 maskbits_from_int 20 = Twenty
  68 maskbits_from_int 21 = TwentyOne
  69 maskbits_from_int 22 = TwentyTwo
  70 maskbits_from_int 23 = TwentyThree
  71 maskbits_from_int 24 = TwentyFour
  72 maskbits_from_int 25 = TwentyFive
  73 maskbits_from_int 26 = TwentySix
  74 maskbits_from_int 27 = TwentySeven
  75 maskbits_from_int 28 = TwentyEight
  76 maskbits_from_int 29 = TwentyNine
  77 maskbits_from_int 30 = Thirty
  78 maskbits_from_int 31 = ThirtyOne
  79 maskbits_from_int 32 = ThirtyTwo
  80 maskbits_from_int _ = None
  81
  82
  83 maskbits_from_string :: String -> Maskbits
  84 maskbits_from_string s =
  85     case (reads s :: [(Int, String)]) of
  86       []   -> None
  87       x:_ -> maskbits_from_int (fst x)