Bump the version number to 0.0.4 in hath.cabal.

[hath.git] / src / IPv4Address.hs

diff --git a/src/IPv4Address.hs b/src/IPv4Address.hs
index dac7ddaf0596e9fba46b077d4321e88149d23b88..7c4436781099b5be4ae98434b0455772145e9ab8 100644 (file)
--- a/src/IPv4Address.hs
+++ b/src/IPv4Address.hs
@@ -1,8 +1,7 @@
-module IPv4Address
-( ipv4address_tests,
+module IPv4Address(
+  ipv4address_properties,
+  ipv4address_tests,
   IPv4Address(..),
-  max_address,
-  min_address,
   most_sig_bit_different,
 ) where
 
@@ -10,7 +9,8 @@ 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 Maskable
 import Maskbits
@@ -165,18 +165,64 @@ instance Maskable IPv4Address where
        new_addr3 { octet1 = (apply_mask oct1 Zero bit) }
 
 
+instance Bounded IPv4Address where
+  -- | The minimum possible IPv4 address, 0.0.0.0.
+  minBound = IPv4Address minBound minBound minBound minBound
 
--- | The minimum possible IPv4 address, 0.0.0.0.
-min_address :: IPv4Address
-min_address =
-  IPv4Address min_octet min_octet min_octet min_octet
+  -- | The maximum possible IPv4 address, 255.255.255.255.
+  maxBound = IPv4Address maxBound maxBound maxBound maxBound
 
 
--- | The maximum possible IPv4 address, 255.255.255.255.
-max_address :: IPv4Address
-max_address =
-  IPv4Address max_octet max_octet max_octet max_octet
 
+-- | 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 = octet_to_int (octet1 addr)
+    oct2 = octet_to_int (octet2 addr)
+    oct3 = octet_to_int (octet3 addr)
+    oct4 = octet_to_int (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
 
 -- | Given two addresses, find the number of the most significant bit
 --   where they differ. If the addresses are the same, return
@@ -292,6 +338,29 @@ most_sig_bit_different addr1 addr2
     oct4b = (octet4 addr2)
 
 
+-- Test lists.
+ipv4address_tests :: Test
+ipv4address_tests =
+  testGroup "IPv4 Address Tests" [
+    test_enum,
+    test_maxBound,
+    test_minBound,
+    test_most_sig_bit_different1,
+    test_most_sig_bit_different2 ]
+
+ipv4address_properties :: Test
+ipv4address_properties =
+  testGroup
+    "IPv4 Address Properties "
+    [ testProperty
+        "fromEnum/toEnum are inverses"
+        prop_from_enum_to_enum_inverses ]
+
+-- QuickCheck properties
+prop_from_enum_to_enum_inverses :: Int -> Property
+prop_from_enum_to_enum_inverses x =
+  (0 <= x) && (x <= 2^(32 :: Integer) - 1) ==>
+    fromEnum (toEnum x :: IPv4Address) == x
 
 -- HUnit Tests
 mk_testaddr :: Int -> Int -> Int -> Int -> IPv4Address
@@ -303,6 +372,31 @@ mk_testaddr a b c d =
     oct3 = fromJust $ octet_from_int c
     oct4 = fromJust $ octet_from_int d
 
+test_minBound :: Test
+test_minBound =
+  testCase desc $ assertEqual desc expected actual
+  where
+    desc = "minBound should be 0.0.0.0"
+    expected = mk_testaddr 0 0 0 0
+    actual = minBound :: IPv4Address
+
+test_maxBound :: Test
+test_maxBound =
+  testCase desc $ assertEqual desc expected actual
+  where
+    desc = "maxBound should be 255.255.255.255"
+    expected = mk_testaddr 255 255 255 255
+    actual = maxBound :: IPv4Address
+
+test_enum :: Test
+test_enum =
+  testCase desc $ assertEqual desc expected actual
+  where
+    desc = "enumerating a /24 gives the correct addresses"
+    expected = ["192.168.0." ++ (show x) | x <- [0..255::Int] ]
+    lb = mk_testaddr 192 168 0 0
+    ub = mk_testaddr 192 168 0 255
+    actual = map show [lb..ub]
 
 test_most_sig_bit_different1 :: Test
 test_most_sig_bit_different1 =
@@ -329,8 +423,3 @@ test_most_sig_bit_different2 =
     bit = most_sig_bit_different addr1 addr2
 
 
-ipv4address_tests :: Test
-ipv4address_tests =
-  testGroup "IPv4 Address Tests" [
-    test_most_sig_bit_different1,
-    test_most_sig_bit_different2 ]