X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FOctet.hs;h=55f075e8a5810247dc9d7df2342b741ea6f82d30;hb=eee156f562f9c1c1194a67cef12f146304d88ce9;hp=aaff3d2e0415a5029a13b5bb9fe957b449e26bd5;hpb=1b7390b71484de63c8ded01371a1dd2adf93909e;p=hath.git

diff --git a/src/Octet.hs b/src/Octet.hs
index aaff3d2..55f075e 100644
--- a/src/Octet.hs
+++ b/src/Octet.hs
@@ -1,63 +1,216 @@
-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.
-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))
-
-
-
-octet_from_int :: Int -> 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 > 128) then One else Zero
-      a2 = if ((x `mod` 128) >= 64) then One else Zero
-      a3 = if ((x `mod` 64)  >= 32) then One else Zero
-      a4 = if ((x `mod` 32)  >= 16) then One else Zero
-      a5 = if ((x `mod` 16)  >= 8)  then One else Zero
-      a6 = if ((x `mod` 8)   >= 4)  then One else Zero
-      a7 = if ((x `mod` 4)   >= 2)  then One else Zero
-      a8 = if ((x `mod` 2)   == 1)  then One else Zero
-
-
-octet_from_string :: String -> Octet
-octet_from_string s =
+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
-      []   -> Octet.None
-      x:_ -> octet_from_int (fst x)
+      []              -> []
+      (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
 
 
--- The octet with the least possible value.
-min_octet :: Octet
-min_octet = Octet Zero Zero Zero Zero Zero Zero Zero Zero
+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
 
 
--- The octet with the greatest possible value.
-max_octet :: Octet
-max_octet = Octet One One One One One One One One
+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