X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FOctet.hs;h=2e372fd4a489c14963508328253e466903d0e333;hb=e8b41784eaa68049f7a7354916c9c9920050db70;hp=e0a4bf655c1ece922a37d5fcdc8f2634957a1a3d;hpb=d4f46f4d52b3d51c2eb59a4aa818d4f23f14203d;p=hath.git diff --git a/src/Octet.hs b/src/Octet.hs index e0a4bf6..2e372fd 100644 --- a/src/Octet.hs +++ b/src/Octet.hs @@ -1,56 +1,164 @@ -module Octet where - -import Bit - --- An Octet consists of eight bits. For our purposes, the most --- significant bit will come "first." That is, b1 is in the 2^7 --- place while b8 is in the 2^0 place. -data Octet = None | Octet { b1 :: Bit, - b2 :: Bit, - b3 :: Bit, - b4 :: Bit, - b5 :: Bit, - b6 :: Bit, - b7 :: Bit, - b8 :: Bit } - deriving (Eq, Show) - --- Convert each bit to its integer value, and multiply by the --- appropriate power of two. Sum them up, and we should get an integer --- between 0 and 255. +module Octet +where + +import Data.Maybe (fromJust) +import Test.HUnit +import Test.QuickCheck + +import Bit as B +import Maskable +import Maskbits + +-- | An Octet consists of eight bits. For our purposes, the most +-- significant bit will come "first." That is, b1 is in the 2^7 +-- place while b8 is in the 2^0 place. +data Octet = + Octet { b1 :: Bit, + b2 :: Bit, + b3 :: Bit, + b4 :: Bit, + b5 :: Bit, + b6 :: Bit, + b7 :: Bit, + b8 :: Bit } + deriving (Eq) + + +instance Show Octet where + show oct = show (octet_to_int oct) + + +instance Arbitrary Octet where + arbitrary = do + a1 <- arbitrary :: Gen Bit + a2 <- arbitrary :: Gen Bit + a3 <- arbitrary :: Gen Bit + a4 <- arbitrary :: Gen Bit + a5 <- arbitrary :: Gen Bit + a6 <- arbitrary :: Gen Bit + a7 <- arbitrary :: Gen Bit + a8 <- arbitrary :: Gen Bit + return (Octet a1 a2 a3 a4 a5 a6 a7 a8) + + +instance Maskable Octet where + apply_mask oct Eight _ = oct + + apply_mask oct Seven bit = + oct { b8 = bit } + + apply_mask oct Six bit = + oct { b8 = bit, b7 = bit } + + apply_mask oct Five bit = + oct { b8 = bit, b7 = bit, b6 = bit } + + apply_mask oct Four bit = + oct { b8 = bit, b7 = bit, b6 = bit, b5 = bit } + + apply_mask oct Three bit = + oct { b8 = bit, b7 = bit, b6 = bit, b5 = bit, b4 = bit } + + apply_mask oct Two bit = + oct { b8 = bit, b7 = bit, b6 = bit, b5 = bit, b4 = bit, b3 = bit } + + apply_mask oct Maskbits.One bit = + oct { b8 = bit, b7 = bit, b6 = bit, b5 = bit, + b4 = bit, b3 = bit, b2 = bit } + + apply_mask oct Maskbits.Zero bit = + oct { b8 = bit, b7 = bit, b6 = bit, b5 = bit, + b4 = bit, b3 = bit, b2 = bit, b1 = bit } + + -- The Maskbits must be in [Eight..ThirtyTwo]. + apply_mask oct _ _ = oct + + +-- | Convert each bit to its integer value, and multiply by the +-- appropriate power of two. Sum them up, and we should get an integer +-- between 0 and 255. octet_to_int :: Octet -> Int octet_to_int x = - 128 * (bit_to_int (b1 x)) + - 64 * (bit_to_int (b2 x)) + - 32 * (bit_to_int (b3 x)) + - 16 * (bit_to_int (b4 x)) + - 8 * (bit_to_int (b5 x)) + - 4 * (bit_to_int (b6 x)) + - 2 * (bit_to_int (b7 x)) + - 0 * (bit_to_int (b8 x)) + 128 * (bit_to_int (b1 x)) + + 64 * (bit_to_int (b2 x)) + + 32 * (bit_to_int (b3 x)) + + 16 * (bit_to_int (b4 x)) + + 8 * (bit_to_int (b5 x)) + + 4 * (bit_to_int (b6 x)) + + 2 * (bit_to_int (b7 x)) + + 1 * (bit_to_int (b8 x)) -octet_from_int :: Int -> Octet +octet_from_int :: Int -> Maybe Octet octet_from_int x - | (x < 0) || (x > 255) = Octet.None - | otherwise = (Octet a1 a2 a3 a4 a5 a6 a7 a8) - where - a1 = if (x `mod` 128) > 0 then One else Zero - a2 = if (x `mod` 64) > 0 then One else Zero - a3 = if (x `mod` 32) > 0 then One else Zero - a4 = if (x `mod` 16) > 0 then One else Zero - a5 = if (x `mod` 8) > 0 then One else Zero - a6 = if (x `mod` 4) > 0 then One else Zero - a7 = if (x `mod` 2) > 0 then One else Zero - a8 = if (x `mod` 1) > 0 then One else Zero - - --- The octet with the least possible value. + | (x < 0) || (x > 255) = Nothing + | otherwise = Just (Octet a1 a2 a3 a4 a5 a6 a7 a8) + where + a1 = if (x >= 128) then B.One else B.Zero + a2 = if ((x `mod` 128) >= 64) then B.One else B.Zero + a3 = if ((x `mod` 64) >= 32) then B.One else B.Zero + a4 = if ((x `mod` 32) >= 16) then B.One else B.Zero + a5 = if ((x `mod` 16) >= 8) then B.One else B.Zero + a6 = if ((x `mod` 8) >= 4) then B.One else B.Zero + a7 = if ((x `mod` 4) >= 2) then B.One else B.Zero + a8 = if ((x `mod` 2) == 1) then B.One else B.Zero + + +octet_from_string :: String -> Maybe Octet +octet_from_string s = + case (reads s :: [(Int, String)]) of + [] -> Nothing + x:_ -> octet_from_int (fst x) + + +-- | The octet with the least possible value. min_octet :: Octet -min_octet = Octet Zero Zero Zero Zero Zero Zero Zero Zero +min_octet = + Octet B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero --- The octet with the greatest possible value. +-- | The octet with the greatest possible value. max_octet :: Octet -max_octet = Octet One One One One One One One One +max_octet = + Octet B.One B.One B.One B.One B.One B.One B.One B.One + + + +-- HUnit Tests +test_octet_from_int1 :: Test +test_octet_from_int1 = + TestCase $ assertEqual "octet_from_int 128 should parse as 10000000" oct1 oct2 + where + oct1 = Octet B.One B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero + oct2 = fromJust $ octet_from_int 128 + +test_octet_mask1 :: Test +test_octet_mask1 = + TestCase $ + assertEqual + "The network bits of 255/4 should equal 240" + oct2 + (apply_mask oct1 Four B.Zero) + where + oct1 = fromJust $ octet_from_int 255 + oct2 = fromJust $ octet_from_int 240 + + +test_octet_mask2 :: Test +test_octet_mask2 = + TestCase $ + assertEqual + "The network bits of 255/1 should equal 128" + oct2 + (apply_mask oct1 Maskbits.One B.Zero) + where + oct1 = fromJust $ octet_from_int 255 + oct2 = fromJust $ octet_from_int 128 + + +octet_tests :: [Test] +octet_tests = + [ test_octet_from_int1, + test_octet_mask1, + test_octet_mask2 ]