-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 = 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.
-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))
-
-
--- The octet with the least possible value.
-min_octet :: Octet
-min_octet = Octet Zero Zero Zero Zero Zero Zero Zero Zero
-
-
--- The octet with the greatest possible value.
-max_octet :: Octet
-max_octet = Octet One One One One One One One One
+module Octet (
+ Octet(..),
+ octet_properties,
+ octet_tests )
+where
+
+import Test.QuickCheck ( Gen ) -- Not re-exported by tasty
+import Test.Tasty ( TestTree, testGroup )
+import Test.Tasty.HUnit ( (@?=), testCase )
+import Test.Tasty.QuickCheck (
+ Arbitrary(..),
+ Property,
+ (==>),
+ testProperty )
+
+import Bit as B (Bit(..))
+import Maskable (Maskable(..))
+import Maskbits (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 (fromEnum 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
+
+
+instance Ord Octet where
+ (Octet x1 x2 x3 x4 x5 x6 x7 x8) <= (Octet y1 y2 y3 y4 y5 y6 y7 y8)
+ | x1 > y1 = False
+ | x2 > y2 = False
+ | x3 > y3 = False
+ | x4 > y4 = False
+ | x5 > y5 = False
+ | x6 > y6 = False
+ | x7 > y7 = False
+ | x8 > y8 = False
+ | otherwise = True
+
+
+instance Bounded Octet where
+ -- | The octet with the least possible value.
+ minBound =
+ Octet B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
+
+ -- | The octet with the greatest possible value.
+ maxBound =
+ Octet B.One B.One B.One B.One B.One B.One B.One B.One
+
+
+instance Enum Octet where
+
+ -- | Create an 'Octet' from an 'Int'. The docs for Enum say we
+ -- should throw a runtime error on out-of-bounds, so we do.
+ toEnum x
+ | x < minBound || x > maxBound = error "octet out of bounds"
+ | otherwise = 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
+
+ -- | 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.
+ fromEnum x =
+ 128 * (fromEnum (b1 x)) +
+ 64 * (fromEnum (b2 x)) +
+ 32 * (fromEnum (b3 x)) +
+ 16 * (fromEnum (b4 x)) +
+ 8 * (fromEnum (b5 x)) +
+ 4 * (fromEnum (b6 x)) +
+ 2 * (fromEnum (b7 x)) +
+ 1 * (fromEnum (b8 x))
+
+
+
+instance Read Octet where
+ readsPrec _ s =
+ case (reads s :: [(Int, String)]) of
+ [] -> []
+ (x,leftover):_ -> go x leftover
+ where
+ go :: Int -> String -> [(Octet, String)]
+ go x' leftover'
+ | x' < minBound || x' > maxBound = []
+ | otherwise = [(toEnum x', leftover')]
+
+
+-- Test lists.
+octet_tests :: TestTree
+octet_tests =
+ testGroup "Octet Tests" [
+ test_octet_from_int1,
+ test_octet_mask1,
+ test_octet_mask2 ]
+
+octet_properties :: TestTree
+octet_properties =
+ testGroup
+ "Octet Properties "
+ [ prop_from_enum_to_enum_inverses,
+ prop_read_show_inverses ]
+
+-- QuickCheck properties
+prop_from_enum_to_enum_inverses :: TestTree
+prop_from_enum_to_enum_inverses =
+ testProperty "fromEnum and toEnum are inverses" prop
+ where
+ prop :: Int -> Property
+ prop x =
+ (0 <= x) && (x <= 255) ==>
+ fromEnum (toEnum x :: Octet) == x
+
+prop_read_show_inverses :: TestTree
+prop_read_show_inverses =
+ testProperty "read and show are inverses" prop
+ where
+ prop :: Int -> Property
+ prop x = (0 <= x) && (x <= 255) ==> x' == x
+ where
+ oct :: Octet
+ oct = read $ show x
+
+ x' :: Int
+ x' = read $ show oct
+
+
+-- HUnit Tests
+test_octet_from_int1 :: TestTree
+test_octet_from_int1 =
+ testCase desc $ actual @?= expected
+ where
+ desc = "octet_from_int 128 should parse as 10000000"
+ expected = Octet B.One B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
+ actual = toEnum 128
+
+
+test_octet_mask1 :: TestTree
+test_octet_mask1 =
+ testCase desc $ actual @?= expected
+ where
+ desc = "The network bits of 255/4 should equal 240"
+ expected = toEnum 240 :: Octet
+ actual = apply_mask (toEnum 255) Four B.Zero
+
+
+test_octet_mask2 :: TestTree
+test_octet_mask2 =
+ testCase desc $ actual @?= expected
+ where
+ desc = "The network bits of 255/1 should equal 128"
+ expected = toEnum 128 :: Octet
+ actual = apply_mask (toEnum 255) Maskbits.One B.Zero
projects / hath.git / blobdiff