-module Octet
+module Octet (
+ Octet(..),
+ octet_from_int,
+ octet_properties,
+ octet_tests,
+ )
where
import Data.Maybe (fromJust)
-
import Test.HUnit (assertEqual)
import Test.Framework (Test, testGroup)
import Test.Framework.Providers.HUnit (testCase)
-
-import Test.QuickCheck (Arbitrary(..), Gen)
+import Test.Framework.Providers.QuickCheck2 (testProperty)
+import Test.QuickCheck (Arbitrary(..), Gen, Property, (==>))
import Bit as B
import Maskable
instance Show Octet where
- show oct = show (octet_to_int oct)
+ show oct = show (fromEnum oct)
instance Arbitrary Octet where
-- maxBound), so the fromJust here doesn't introduce any additional
-- badness.
toEnum = fromJust . octet_from_int
- fromEnum = octet_to_int
--- | 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))
+ -- | 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 * (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))
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)
+instance Read Octet where
+ readsPrec _ = \s ->
+ case (reads s :: [(Int, String)]) of
+ [] -> []
+ (x,leftover):_ -> case (octet_from_int x) of
+ Nothing -> []
+ Just oct -> [(oct, leftover)]
+
+-- Test lists.
+octet_tests :: Test
+octet_tests =
+ testGroup "Octet Tests" [
+ test_octet_from_int1,
+ test_octet_mask1,
+ test_octet_mask2 ]
+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
+ oct :: Octet
+ oct = read $ show x
+
+ x' :: Int
+ x' = read $ show oct
-- HUnit Tests
test_octet_from_int1 :: Test
desc = "The network bits of 255/1 should equal 128"
oct1 = fromJust $ octet_from_int 255
oct2 = fromJust $ octet_from_int 128
-
-
-octet_tests :: Test
-octet_tests =
- testGroup "Octet Tests" [
- test_octet_from_int1,
- test_octet_mask1,
- test_octet_mask2 ]