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)
  42
  43
  44 instance Show Maskbits where
  45     show None        = "None"
  46     show Zero        = "0"
  47     show One         = "1"
  48     show Two         = "2"
  49     show Three       = "3"
  50     show Four        = "4"
  51     show Five        = "5"
  52     show Six         = "6"
  53     show Seven       = "7"
  54     show Eight       = "8"
  55     show Nine        = "9"
  56     show Ten         = "10"
  57     show Eleven      = "11"
  58     show Twelve      = "12"
  59     show Thirteen    = "13"
  60     show Fourteen    = "14"
  61     show Fifteen     = "15"
  62     show Sixteen     = "16"
  63     show Seventeen   = "17"
  64     show Eighteen    = "18"
  65     show Nineteen    = "19"
  66     show Twenty      = "20"
  67     show TwentyOne   = "21"
  68     show TwentyTwo   = "22"
  69     show TwentyThree = "23"
  70     show TwentyFour  = "24"
  71     show TwentyFive  = "25"
  72     show TwentySix   = "26"
  73     show TwentySeven = "27"
  74     show TwentyEight = "28"
  75     show TwentyNine  = "29"
  76     show Thirty      = "30"
  77     show ThirtyOne   = "31"
  78     show ThirtyTwo   = "32"
  79
  80
  81
  82 -- There are only 32 bits in an IPv4 address, so there
  83 -- can't be more bits than that in the mask.
  84 maskbits_from_int :: Int -> Maskbits
  85 maskbits_from_int 0  = Zero
  86 maskbits_from_int 1  = One
  87 maskbits_from_int 2  = Two
  88 maskbits_from_int 3  = Three
  89 maskbits_from_int 4  = Four
  90 maskbits_from_int 5  = Five
  91 maskbits_from_int 6  = Six
  92 maskbits_from_int 7  = Seven
  93 maskbits_from_int 8  = Eight
  94 maskbits_from_int 9  = Nine
  95 maskbits_from_int 10 = Ten
  96 maskbits_from_int 11 = Eleven
  97 maskbits_from_int 12 = Twelve
  98 maskbits_from_int 13 = Thirteen
  99 maskbits_from_int 14 = Fourteen
 100 maskbits_from_int 15 = Fifteen
 101 maskbits_from_int 16 = Sixteen
 102 maskbits_from_int 17 = Seventeen
 103 maskbits_from_int 18 = Eighteen
 104 maskbits_from_int 19 = Nineteen
 105 maskbits_from_int 20 = Twenty
 106 maskbits_from_int 21 = TwentyOne
 107 maskbits_from_int 22 = TwentyTwo
 108 maskbits_from_int 23 = TwentyThree
 109 maskbits_from_int 24 = TwentyFour
 110 maskbits_from_int 25 = TwentyFive
 111 maskbits_from_int 26 = TwentySix
 112 maskbits_from_int 27 = TwentySeven
 113 maskbits_from_int 28 = TwentyEight
 114 maskbits_from_int 29 = TwentyNine
 115 maskbits_from_int 30 = Thirty
 116 maskbits_from_int 31 = ThirtyOne
 117 maskbits_from_int 32 = ThirtyTwo
 118 maskbits_from_int _ = None
 119
 120
 121 maskbits_from_string :: String -> Maskbits
 122 maskbits_from_string s =
 123     case (reads s :: [(Int, String)]) of
 124       []   -> None
 125       x:_ -> maskbits_from_int (fst x)