src/Maskbits.hs

   1 module Maskbits
   2 ( Maskbits(..),
   3   decrement,
   4   maskbits_from_string
   5 ) where
   6
   7 import Test.QuickCheck
   8
   9 -- A type representing the number of bits in a CIDR netmask.
  10 data Maskbits = None
  11               | Zero
  12               | One
  13               | Two
  14               | Three
  15               | Four
  16               | Five
  17               | Six
  18               | Seven
  19               | Eight
  20               | Nine
  21               | Ten
  22               | Eleven
  23               | Twelve
  24               | Thirteen
  25               | Fourteen
  26               | Fifteen
  27               | Sixteen
  28               | Seventeen
  29               | Eighteen
  30               | Nineteen
  31               | Twenty
  32               | TwentyOne
  33               | TwentyTwo
  34               | TwentyThree
  35               | TwentyFour
  36               | TwentyFive
  37               | TwentySix
  38               | TwentySeven
  39               | TwentyEight
  40               | TwentyNine
  41               | Thirty
  42               | ThirtyOne
  43               | ThirtyTwo
  44               deriving (Eq, Ord)
  45
  46
  47 instance Show Maskbits where
  48     show None        = "None"
  49     show Zero        = "0"
  50     show One         = "1"
  51     show Two         = "2"
  52     show Three       = "3"
  53     show Four        = "4"
  54     show Five        = "5"
  55     show Six         = "6"
  56     show Seven       = "7"
  57     show Eight       = "8"
  58     show Nine        = "9"
  59     show Ten         = "10"
  60     show Eleven      = "11"
  61     show Twelve      = "12"
  62     show Thirteen    = "13"
  63     show Fourteen    = "14"
  64     show Fifteen     = "15"
  65     show Sixteen     = "16"
  66     show Seventeen   = "17"
  67     show Eighteen    = "18"
  68     show Nineteen    = "19"
  69     show Twenty      = "20"
  70     show TwentyOne   = "21"
  71     show TwentyTwo   = "22"
  72     show TwentyThree = "23"
  73     show TwentyFour  = "24"
  74     show TwentyFive  = "25"
  75     show TwentySix   = "26"
  76     show TwentySeven = "27"
  77     show TwentyEight = "28"
  78     show TwentyNine  = "29"
  79     show Thirty      = "30"
  80     show ThirtyOne   = "31"
  81     show ThirtyTwo   = "32"
  82
  83
  84 instance Arbitrary Maskbits where
  85     arbitrary = elements [ Zero,
  86                            One,
  87                            Two,
  88                            Three,
  89                            Four,
  90                            Five,
  91                            Six,
  92                            Seven,
  93                            Eight,
  94                            Nine,
  95                            Ten,
  96                            Eleven,
  97                            Twelve,
  98                            Thirteen,
  99                            Fourteen,
 100                            Fifteen,
 101                            Sixteen,
 102                            Seventeen,
 103                            Eighteen,
 104                            Nineteen,
 105                            Twenty,
 106                            TwentyOne,
 107                            TwentyTwo,
 108                            TwentyThree,
 109                            TwentyFour,
 110                            TwentyFive,
 111                            TwentySix,
 112                            TwentySeven,
 113                            TwentyEight,
 114                            TwentyNine,
 115                            Thirty,
 116                            ThirtyOne,
 117                            ThirtyTwo ]
 118
 119
 120
 121 -- There are only 32 bits in an IPv4 address, so there
 122 -- can't be more bits than that in the mask.
 123 maskbits_from_int :: Int -> Maskbits
 124 maskbits_from_int 0  = Zero
 125 maskbits_from_int 1  = One
 126 maskbits_from_int 2  = Two
 127 maskbits_from_int 3  = Three
 128 maskbits_from_int 4  = Four
 129 maskbits_from_int 5  = Five
 130 maskbits_from_int 6  = Six
 131 maskbits_from_int 7  = Seven
 132 maskbits_from_int 8  = Eight
 133 maskbits_from_int 9  = Nine
 134 maskbits_from_int 10 = Ten
 135 maskbits_from_int 11 = Eleven
 136 maskbits_from_int 12 = Twelve
 137 maskbits_from_int 13 = Thirteen
 138 maskbits_from_int 14 = Fourteen
 139 maskbits_from_int 15 = Fifteen
 140 maskbits_from_int 16 = Sixteen
 141 maskbits_from_int 17 = Seventeen
 142 maskbits_from_int 18 = Eighteen
 143 maskbits_from_int 19 = Nineteen
 144 maskbits_from_int 20 = Twenty
 145 maskbits_from_int 21 = TwentyOne
 146 maskbits_from_int 22 = TwentyTwo
 147 maskbits_from_int 23 = TwentyThree
 148 maskbits_from_int 24 = TwentyFour
 149 maskbits_from_int 25 = TwentyFive
 150 maskbits_from_int 26 = TwentySix
 151 maskbits_from_int 27 = TwentySeven
 152 maskbits_from_int 28 = TwentyEight
 153 maskbits_from_int 29 = TwentyNine
 154 maskbits_from_int 30 = Thirty
 155 maskbits_from_int 31 = ThirtyOne
 156 maskbits_from_int 32 = ThirtyTwo
 157 maskbits_from_int _ = None
 158
 159
 160 maskbits_from_string :: String -> Maskbits
 161 maskbits_from_string s =
 162     case (reads s :: [(Int, String)]) of
 163       []   -> None
 164       x:_ -> maskbits_from_int (fst x)
 165
 166
 167
 168 decrement :: Maskbits -> Maskbits
 169 decrement None = None
 170 decrement Zero = None
 171 decrement One = Zero
 172 decrement Two = One
 173 decrement Three = Two
 174 decrement Four = Three
 175 decrement Five = Four
 176 decrement Six = Five
 177 decrement Seven = Six
 178 decrement Eight = Seven
 179 decrement Nine = Eight
 180 decrement Ten = Nine
 181 decrement Eleven = Ten
 182 decrement Twelve = Eleven
 183 decrement Thirteen = Twelve
 184 decrement Fourteen = Thirteen
 185 decrement Fifteen = Fourteen
 186 decrement Sixteen = Fifteen
 187 decrement Seventeen = Sixteen
 188 decrement Eighteen = Seventeen
 189 decrement Nineteen = Eighteen
 190 decrement Twenty = Nineteen
 191 decrement TwentyOne = Twenty
 192 decrement TwentyTwo = TwentyOne
 193 decrement TwentyThree = TwentyTwo
 194 decrement TwentyFour = TwentyThree
 195 decrement TwentyFive = TwentyFour
 196 decrement TwentySix = TwentyFive
 197 decrement TwentySeven = TwentySix
 198 decrement TwentyEight = TwentySeven
 199 decrement TwentyNine = TwentyEight
 200 decrement Thirty = TwentyNine
 201 decrement ThirtyOne = Thirty
 202 decrement ThirtyTwo = ThirtyOne