src/Maskbits.hs

   1 module Maskbits
   2 ( Maskbits(..),
   3   decrement,
   4   maskbits_from_string
   5 ) where
   6
   7 -- A type representing the number of bits in a CIDR netmask.
   8 data Maskbits = None
   9               | Zero
  10               | One
  11               | Two
  12               | Three
  13               | Four
  14               | Five
  15               | Six
  16               | Seven
  17               | Eight
  18               | Nine
  19               | Ten
  20               | Eleven
  21               | Twelve
  22               | Thirteen
  23               | Fourteen
  24               | Fifteen
  25               | Sixteen
  26               | Seventeen
  27               | Eighteen
  28               | Nineteen
  29               | Twenty
  30               | TwentyOne
  31               | TwentyTwo
  32               | TwentyThree
  33               | TwentyFour
  34               | TwentyFive
  35               | TwentySix
  36               | TwentySeven
  37               | TwentyEight
  38               | TwentyNine
  39               | Thirty
  40               | ThirtyOne
  41               | ThirtyTwo
  42               deriving (Eq, Ord)
  43
  44
  45 instance Show Maskbits where
  46     show None        = "None"
  47     show Zero        = "0"
  48     show One         = "1"
  49     show Two         = "2"
  50     show Three       = "3"
  51     show Four        = "4"
  52     show Five        = "5"
  53     show Six         = "6"
  54     show Seven       = "7"
  55     show Eight       = "8"
  56     show Nine        = "9"
  57     show Ten         = "10"
  58     show Eleven      = "11"
  59     show Twelve      = "12"
  60     show Thirteen    = "13"
  61     show Fourteen    = "14"
  62     show Fifteen     = "15"
  63     show Sixteen     = "16"
  64     show Seventeen   = "17"
  65     show Eighteen    = "18"
  66     show Nineteen    = "19"
  67     show Twenty      = "20"
  68     show TwentyOne   = "21"
  69     show TwentyTwo   = "22"
  70     show TwentyThree = "23"
  71     show TwentyFour  = "24"
  72     show TwentyFive  = "25"
  73     show TwentySix   = "26"
  74     show TwentySeven = "27"
  75     show TwentyEight = "28"
  76     show TwentyNine  = "29"
  77     show Thirty      = "30"
  78     show ThirtyOne   = "31"
  79     show ThirtyTwo   = "32"
  80
  81
  82
  83 -- There are only 32 bits in an IPv4 address, so there
  84 -- can't be more bits than that in the mask.
  85 maskbits_from_int :: Int -> Maskbits
  86 maskbits_from_int 0  = Zero
  87 maskbits_from_int 1  = One
  88 maskbits_from_int 2  = Two
  89 maskbits_from_int 3  = Three
  90 maskbits_from_int 4  = Four
  91 maskbits_from_int 5  = Five
  92 maskbits_from_int 6  = Six
  93 maskbits_from_int 7  = Seven
  94 maskbits_from_int 8  = Eight
  95 maskbits_from_int 9  = Nine
  96 maskbits_from_int 10 = Ten
  97 maskbits_from_int 11 = Eleven
  98 maskbits_from_int 12 = Twelve
  99 maskbits_from_int 13 = Thirteen
 100 maskbits_from_int 14 = Fourteen
 101 maskbits_from_int 15 = Fifteen
 102 maskbits_from_int 16 = Sixteen
 103 maskbits_from_int 17 = Seventeen
 104 maskbits_from_int 18 = Eighteen
 105 maskbits_from_int 19 = Nineteen
 106 maskbits_from_int 20 = Twenty
 107 maskbits_from_int 21 = TwentyOne
 108 maskbits_from_int 22 = TwentyTwo
 109 maskbits_from_int 23 = TwentyThree
 110 maskbits_from_int 24 = TwentyFour
 111 maskbits_from_int 25 = TwentyFive
 112 maskbits_from_int 26 = TwentySix
 113 maskbits_from_int 27 = TwentySeven
 114 maskbits_from_int 28 = TwentyEight
 115 maskbits_from_int 29 = TwentyNine
 116 maskbits_from_int 30 = Thirty
 117 maskbits_from_int 31 = ThirtyOne
 118 maskbits_from_int 32 = ThirtyTwo
 119 maskbits_from_int _ = None
 120
 121
 122 maskbits_from_string :: String -> Maskbits
 123 maskbits_from_string s =
 124     case (reads s :: [(Int, String)]) of
 125       []   -> None
 126       x:_ -> maskbits_from_int (fst x)
 127
 128
 129
 130 decrement :: Maskbits -> Maskbits
 131 decrement None = None
 132 decrement Zero = None
 133 decrement One = Zero
 134 decrement Two = One
 135 decrement Three = Two
 136 decrement Four = Three
 137 decrement Five = Four
 138 decrement Six = Five
 139 decrement Seven = Six
 140 decrement Eight = Seven
 141 decrement Nine = Eight
 142 decrement Ten = Nine
 143 decrement Eleven = Ten
 144 decrement Twelve = Eleven
 145 decrement Thirteen = Twelve
 146 decrement Fourteen = Thirteen
 147 decrement Fifteen = Fourteen
 148 decrement Sixteen = Fifteen
 149 decrement Seventeen = Sixteen
 150 decrement Eighteen = Seventeen
 151 decrement Nineteen = Eighteen
 152 decrement Twenty = Nineteen
 153 decrement TwentyOne = Twenty
 154 decrement TwentyTwo = TwentyOne
 155 decrement TwentyThree = TwentyTwo
 156 decrement TwentyFour = TwentyThree
 157 decrement TwentyFive = TwentyFour
 158 decrement TwentySix = TwentyFive
 159 decrement TwentySeven = TwentySix
 160 decrement TwentyEight = TwentySeven
 161 decrement TwentyNine = TwentyEight
 162 decrement Thirty = TwentyNine
 163 decrement ThirtyOne = Thirty
 164 decrement ThirtyTwo = ThirtyOne