-module Octet
+module Octet (
+ Octet(..),
+ octet_properties,
+ octet_tests,
+ )
where
-import Data.Maybe (fromJust)
-import Test.HUnit
-import Test.QuickCheck
+import Test.HUnit (assertEqual)
+import Test.Framework (Test, testGroup)
+import Test.Framework.Providers.HUnit (testCase)
+import Test.Framework.Providers.QuickCheck2 (testProperty)
+import Test.QuickCheck (Arbitrary(..), Gen, Property, (==>))
-import Bit as B
-import Maskable
-import Maskbits
+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
instance Show Octet where
- show oct = show (octet_to_int oct)
+ show oct = show (fromEnum oct)
instance Arbitrary Octet where
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)) +
- 1 * (bit_to_int (b8 x))
-
-
+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 y s
+ | y < minBound || y > maxBound = []
+ | otherwise = [(toEnum y, s)]
+
+
+-- Test lists.
+octet_tests :: Test
+octet_tests =
+ testGroup "Octet Tests" [
+ test_octet_from_int1,
+ test_octet_mask1,
+ test_octet_mask2 ]
-octet_from_int :: Int -> Maybe Octet
-octet_from_int x
- | (x < 0) || (x > 255) = Nothing
- | otherwise = Just (Octet a1 a2 a3 a4 a5 a6 a7 a8)
+octet_properties :: Test
+octet_properties =
+ testGroup
+ "Octet Properties "
+ [ testProperty
+ "fromEnum/toEnum are inverses"
+ prop_from_enum_to_enum_inverses,
+ testProperty
+ "read/show are inverses"
+ prop_read_show_inverses ]
+
+-- QuickCheck properties
+prop_from_enum_to_enum_inverses :: Int -> Property
+prop_from_enum_to_enum_inverses x =
+ (0 <= x) && (x <= 255) ==>
+ fromEnum (toEnum x :: Octet) == x
+
+prop_read_show_inverses :: Int -> Property
+prop_read_show_inverses x =
+ (0 <= x) && (x <= 255) ==> x' == x
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 B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
-
-
--- | The octet with the greatest possible value.
-max_octet :: Octet
-max_octet =
- Octet B.One B.One B.One B.One B.One B.One B.One B.One
-
+ oct :: Octet
+ oct = read $ show x
+ x' :: Int
+ x' = read $ show oct
-- HUnit Tests
test_octet_from_int1 :: Test
test_octet_from_int1 =
- TestCase $ assertEqual "octet_from_int 128 should parse as 10000000" oct1 oct2
+ testCase desc $ assertEqual desc oct1 oct2
where
+ desc = "octet_from_int 128 should parse as 10000000"
oct1 = Octet B.One B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
- oct2 = fromJust $ octet_from_int 128
+ oct2 = toEnum 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)
+ testCase desc $
+ assertEqual desc oct2 (apply_mask oct1 Four B.Zero)
where
- oct1 = fromJust $ octet_from_int 255
- oct2 = fromJust $ octet_from_int 240
+ desc = "The network bits of 255/4 should equal 240"
+ oct1 = toEnum 255
+ oct2 = toEnum 240 :: Octet
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)
+ testCase desc $
+ assertEqual desc 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 ]
+ desc = "The network bits of 255/1 should equal 128"
+ oct1 = toEnum 255
+ oct2 = toEnum 128 :: Octet
projects / hath.git / blobdiff