X-Git-Url: http://gitweb.michael.orlitzky.com/?p=hath.git;a=blobdiff_plain;f=src%2FIPv4Address.hs;h=f4bfc9749cab1adb63ffcb7b0907d0ce3c9ebae2;hp=15e69665e7ab8e22c4bd027b401860d579cf3727;hb=45ac9baca360d0f0dabe4576fb44c1634a50dbf7;hpb=18a81546e7c4ad10574918efb08b2e104e911d73

diff --git a/src/IPv4Address.hs b/src/IPv4Address.hs
index 15e6966..f4bfc97 100644
--- a/src/IPv4Address.hs
+++ b/src/IPv4Address.hs
@@ -1,20 +1,19 @@
 module IPv4Address(
+  IPv4Address(..),
   ipv4address_properties,
   ipv4address_tests,
-  IPv4Address(..),
-  most_sig_bit_different,
-) where
+  most_sig_bit_different )
+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 Maskable
-import Maskbits
-import Octet
+import Maskable (Maskable(..))
+import Maskbits (Maskbits(..))
+import Octet (Octet(..))
 
 data IPv4Address =
   IPv4Address { octet1 :: Octet,
@@ -174,55 +173,40 @@ instance Bounded IPv4Address where
 
 
 
--- | Convert @addr@ to an 'Int' by converting each octet to an 'Int'
---   and shifting the result to the left by 0,8.16, or 24 bits.
-ipv4address_to_int :: IPv4Address -> Int
-ipv4address_to_int addr =
-  (shifted_oct1) + (shifted_oct2) + (shifted_oct3) + oct4
-  where
-    oct1 = fromEnum (octet1 addr)
-    oct2 = fromEnum (octet2 addr)
-    oct3 = fromEnum (octet3 addr)
-    oct4 = fromEnum (octet4 addr)
-
-    shifted_oct1 = oct1 * 2^(24 :: Integer)
-    shifted_oct2 = oct2 * 2^(16 :: Integer)
-    shifted_oct3 = oct3 * 2^(8 :: Integer)
-
-
-
--- | Convert an 'Int' @x@ to an 'IPv4Address'. Each octet of @x@ is
---   right-shifted by the appropriate number of bits, and the fractional
---   part is dropped.
-ipv4address_from_int :: Int -> Maybe IPv4Address
-ipv4address_from_int x
-  | (x < 0) || (x > 2^(32 :: Integer) - 1) = Nothing
-  | otherwise = do
-      -- If the algebra is right, none of these octet_from_int calls
-      -- below can fail since 0 <= x <= 2^32 - 1.
-      oct1 <- octet_from_int shifted_x1
-      oct2 <- octet_from_int shifted_x2
-      oct3 <- octet_from_int shifted_x3
-      oct4 <- octet_from_int x4
-      return $ IPv4Address oct1 oct2 oct3 oct4
-      where
-        -- Chop off the higher octets. x1 = x `mod` 2^32, would be
-        -- redundant.
-        x2 = x `mod` 2^(24 :: Integer)
-        x3 = x `mod` 2^(16 :: Integer)
-        x4 = x `mod` 2^(8  :: Integer)
-        -- Perform right-shifts. x4 doesn't need a shift.
-        shifted_x1 = x `quot` 2^(24 :: Integer)
-        shifted_x2 = x2 `quot` 2^(16 :: Integer)
-        shifted_x3 = x3 `quot` 2^(8 :: Integer)
-
 
 instance Enum IPv4Address 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 . ipv4address_from_int
-  fromEnum = ipv4address_to_int
+  -- | Convert an 'Int' @x@ to an 'IPv4Address'. Each octet of @x@ is
+  --   right-shifted by the appropriate number of bits, and the fractional
+  --   part is dropped.
+  toEnum x =
+    IPv4Address oct1 oct2 oct3 oct4
+    where
+      -- Chop off the higher octets. x1 = x `mod` 2^32, would be
+      -- redundant.
+      x2 = x `mod` 2^(24 :: Integer)
+      x3 = x `mod` 2^(16 :: Integer)
+      x4 = x `mod` 2^(8  :: Integer)
+      -- Perform right-shifts. x4 doesn't need a shift.
+      shifted_x1 = x `quot` 2^(24 :: Integer)
+      shifted_x2 = x2 `quot` 2^(16 :: Integer)
+      shifted_x3 = x3 `quot` 2^(8 :: Integer)
+      oct1 = toEnum shifted_x1
+      oct2 = toEnum shifted_x2
+      oct3 = toEnum shifted_x3
+      oct4 = toEnum x4
+
+  -- | Convert @addr@ to an 'Int' by converting each octet to an 'Int'
+  --   and shifting the result to the left by 0,8.16, or 24 bits.
+  fromEnum addr =
+    (shifted_oct1) + (shifted_oct2) + (shifted_oct3) + oct4
+    where
+      oct1 = fromEnum (octet1 addr)
+      oct2 = fromEnum (octet2 addr)
+      oct3 = fromEnum (octet3 addr)
+      oct4 = fromEnum (octet4 addr)
+      shifted_oct1 = oct1 * 2^(24 :: Integer)
+      shifted_oct2 = oct2 * 2^(16 :: Integer)
+      shifted_oct3 = oct3 * 2^(8 :: Integer)
 
 -- | Given two addresses, find the number of the most significant bit
 --   where they differ. If the addresses are the same, return
@@ -368,10 +352,10 @@ mk_testaddr :: Int -> Int -> Int -> Int -> IPv4Address
 mk_testaddr a b c d =
   IPv4Address oct1 oct2 oct3 oct4
   where
-    oct1 = fromJust $ octet_from_int a
-    oct2 = fromJust $ octet_from_int b
-    oct3 = fromJust $ octet_from_int c
-    oct4 = fromJust $ octet_from_int d
+    oct1 = toEnum a
+    oct2 = toEnum b
+    oct3 = toEnum c
+    oct4 = toEnum d
 
 test_minBound :: Test
 test_minBound =