module Octet (
Octet(..),
- octet_from_int,
octet_properties,
- octet_tests,
- )
+ octet_tests )
where
-import Data.Maybe (fromJust)
-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 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
-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 Enum Octet where
- -- We're supposed to throw a runtime error if you call (succ
- -- maxBound), so the fromJust here doesn't introduce any additional
- -- badness.
- toEnum = fromJust . octet_from_int
+
+ -- | 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 * (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))
-
+ 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))
-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)
- 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
-
instance Read Octet where
- readsPrec _ = \s ->
+ readsPrec _ s =
case (reads s :: [(Int, String)]) of
[] -> []
- (x,leftover):_ -> case (octet_from_int x) of
- Nothing -> []
- Just oct -> [(oct, leftover)]
+ (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 :: Test
+octet_tests :: TestTree
octet_tests =
testGroup "Octet Tests" [
test_octet_from_int1,
test_octet_mask1,
test_octet_mask2 ]
-octet_properties :: Test
+octet_properties :: TestTree
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 ]
+ [ prop_from_enum_to_enum_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
+prop_from_enum_to_enum_inverses :: TestTree
+prop_from_enum_to_enum_inverses =
+ testProperty "fromEnum and toEnum are inverses" prop
where
- oct :: Octet
- oct = read $ show x
+ 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
- x' :: Int
- x' = read $ show oct
-- HUnit Tests
-test_octet_from_int1 :: Test
+test_octet_from_int1 :: TestTree
test_octet_from_int1 =
- testCase desc $ assertEqual desc oct1 oct2
+ testCase desc $ actual @?= expected
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
+ expected = Octet B.One B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
+ actual = toEnum 128
+
-test_octet_mask1 :: Test
+test_octet_mask1 :: TestTree
test_octet_mask1 =
- testCase desc $
- assertEqual desc oct2 (apply_mask oct1 Four B.Zero)
+ testCase desc $ actual @?= expected
where
desc = "The network bits of 255/4 should equal 240"
- oct1 = fromJust $ octet_from_int 255
- oct2 = fromJust $ octet_from_int 240
+ expected = toEnum 240 :: Octet
+ actual = apply_mask (toEnum 255) Four B.Zero
-test_octet_mask2 :: Test
+test_octet_mask2 :: TestTree
test_octet_mask2 =
- testCase desc $
- assertEqual desc oct2 (apply_mask oct1 Maskbits.One B.Zero)
+ testCase desc $ actual @?= expected
where
desc = "The network bits of 255/1 should equal 128"
- oct1 = fromJust $ octet_from_int 255
- oct2 = fromJust $ octet_from_int 128
+ expected = toEnum 128 :: Octet
+ actual = apply_mask (toEnum 255) Maskbits.One B.Zero
projects / hath.git / blobdiff