X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FIPv4Address.hs;h=38aec8dd39c5250279a05357db753c8aa2247cf2;hb=HEAD;hp=15e69665e7ab8e22c4bd027b401860d579cf3727;hpb=18a81546e7c4ad10574918efb08b2e104e911d73;p=hath.git diff --git a/src/IPv4Address.hs b/src/IPv4Address.hs index 15e6966..f9fd8c2 100644 --- a/src/IPv4Address.hs +++ b/src/IPv4Address.hs @@ -1,27 +1,40 @@ module IPv4Address( + IPv4Address(..), ipv4address_properties, ipv4address_tests, - IPv4Address(..), - 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 + most_sig_bit_different ) +where + +import Data.Int ( Int32, Int64 ) +import Data.Word ( Word32 ) + +import Test.Tasty ( TestTree, testGroup ) +import Test.Tasty.HUnit ( (@?=), testCase ) +import Test.Tasty.QuickCheck ( + Arbitrary( arbitrary ), + Gen, + Large, + Property, + Small, + (==>), + testProperty ) + +import Maskable ( Maskable( apply_mask) ) +import Maskbits ( + Maskbits( + Zero, One, Two, Three, Four, Five, Six, Seven, Eight, + Nine, Ten, Eleven, Twelve, Thirteen, Fourteen, Fifteen, Sixteen, + Seventeen, Eighteen, Nineteen, Twenty, TwentyOne, TwentyTwo, TwentyThree, + TwentyFour, TwentyFive, TwentySix, TwentySeven, TwentyEight, TwentyNine, + Thirty, ThirtyOne, ThirtyTwo ) ) +import Octet ( Octet( b1, b2, b3, b4, b5, b6, b7, b8) ) data IPv4Address = IPv4Address { octet1 :: Octet, octet2 :: Octet, octet3 :: Octet, octet4 :: Octet } - deriving (Eq) + deriving (Eq, Ord) instance Show IPv4Address where @@ -174,55 +187,48 @@ 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 signed_x = + IPv4Address oct1 oct2 oct3 oct4 + where + -- Convert the input Int to a Word32 before we proceed. On x86, + -- the Int that we get could be negative (half of all IP + -- addresses correspond to negative numbers), and then the magic + -- below doesn't work. The Word32 type is unsigned, so we do the + -- math on that and then convert everything back to Int later on + -- once we have four much-smaller non-negative numbers. + x = fromIntegral signed_x :: Word32 + + -- 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 = (fromIntegral $ x `mod` (2 ^ (8 :: Integer))) :: Int + -- Perform right-shifts. x4 doesn't need a shift. + shifted_x1 = (fromIntegral $ x `quot` (2 ^ (24 :: Integer))) :: Int + shifted_x2 = (fromIntegral $ x2 `quot` (2 ^ (16 :: Integer))) :: Int + shifted_x3 = (fromIntegral $ x3 `quot` (2 ^ (8 :: Integer))) :: Int + oct1 = toEnum shifted_x1 :: Octet + oct2 = toEnum shifted_x2 :: Octet + oct3 = toEnum shifted_x3 :: Octet + oct4 = toEnum x4 :: 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. + 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 @@ -339,7 +345,7 @@ most_sig_bit_different addr1 addr2 -- Test lists. -ipv4address_tests :: Test +ipv4address_tests :: TestTree ipv4address_tests = testGroup "IPv4 Address Tests" [ test_enum, @@ -347,51 +353,85 @@ ipv4address_tests = test_minBound, test_most_sig_bit_different1, test_most_sig_bit_different2, + test_ord_instance1, + test_ord_instance2, + test_ord_instance3, + test_ord_instance4, test_to_enum ] -ipv4address_properties :: Test +ipv4address_properties :: TestTree ipv4address_properties = testGroup "IPv4 Address Properties " - [ testProperty - "fromEnum/toEnum are inverses" - prop_from_enum_to_enum_inverses ] + [ prop_from_enum_to_enum_inverses_x32, + prop_from_enum_to_enum_inverses_x64 ] -- 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 +-- +-- We have two different tests to show that toEnum and fromEnum are +-- inverses of one another. This part of the code isn't really +-- type-safe, because the stupid Enum class insists that we use a +-- machine 'Int' for our representation. Since IPv4 addresses can +-- correspond to very large 32-bit integers, there's a possibility +-- that our math is wrong in 32- but not 64-bits, and vice-versa. +-- +-- tl;dr we want to ensure that this test passes when the 'Int' type +-- is both 32-bit and 64-bit. + +-- Generate "Small" 64-bit numbers, because almost all 64-bit integers are +-- too large to satisfy our predicate (i.e. also be 32-bit integers). +prop_from_enum_to_enum_inverses_x64 :: TestTree +prop_from_enum_to_enum_inverses_x64 = + testProperty "fromEnum and toEnum are inverses (x64)" prop + where + prop :: (Small Int64) -> Property + prop x = + 0 <= x && x <= (2 ^ (32 :: Integer)) - 1 ==> + fromIntegral (fromEnum (toEnum (fromIntegral x) :: IPv4Address)) == x + +-- According to the QuickCheck documentation, we need the "Large" +-- modifier to ensure that the test cases are drawn from the entire +-- range of Int32 values. +prop_from_enum_to_enum_inverses_x32 :: TestTree +prop_from_enum_to_enum_inverses_x32 = + testProperty "fromEnum and toEnum are inverses (x32)" prop + where + prop :: (Large Int32) -> Bool + prop x = + fromIntegral (fromEnum (toEnum (fromIntegral x) :: IPv4Address)) == x -- HUnit Tests 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 :: Octet + oct2 = toEnum b :: Octet + oct3 = toEnum c :: Octet + oct4 = toEnum d :: Octet -test_minBound :: Test + +test_minBound :: TestTree test_minBound = - testCase desc $ assertEqual desc expected actual + testCase desc $ actual @?= expected where desc = "minBound should be 0.0.0.0" expected = mk_testaddr 0 0 0 0 actual = minBound :: IPv4Address -test_maxBound :: Test + +test_maxBound :: TestTree test_maxBound = - testCase desc $ assertEqual desc expected actual + testCase desc $ actual @?= expected where desc = "maxBound should be 255.255.255.255" expected = mk_testaddr 255 255 255 255 actual = maxBound :: IPv4Address -test_enum :: Test + +test_enum :: TestTree test_enum = - testCase desc $ assertEqual desc expected actual + testCase desc $ actual @?= expected where desc = "enumerating a /24 gives the correct addresses" expected = ["192.168.0." ++ (show x) | x <- [0..255::Int] ] @@ -399,35 +439,80 @@ test_enum = ub = mk_testaddr 192 168 0 255 actual = map show [lb..ub] -test_most_sig_bit_different1 :: Test + +test_most_sig_bit_different1 :: TestTree test_most_sig_bit_different1 = - testCase desc $ assertEqual desc - TwentyFour - bit + testCase desc $ actual @?= expected where desc = "10.1.1.0 and 10.1.0.0 differ in bit 24" addr1 = mk_testaddr 10 1 1 0 addr2 = (mk_testaddr 10 1 0 0) - bit = most_sig_bit_different addr1 addr2 + expected = TwentyFour + actual = most_sig_bit_different addr1 addr2 -test_most_sig_bit_different2 :: Test +test_most_sig_bit_different2 :: TestTree test_most_sig_bit_different2 = - testCase desc $ assertEqual desc - TwentyThree - bit + testCase desc $ actual @?= expected where desc = "10.1.2.0 and 10.1.1.0 differ in bit 23" addr1 = mk_testaddr 10 1 2 0 addr2 = mk_testaddr 10 1 1 0 - bit = most_sig_bit_different addr1 addr2 + expected = TwentyThree + actual = most_sig_bit_different addr1 addr2 -test_to_enum :: Test +test_to_enum :: TestTree test_to_enum = - testCase desc $ assertEqual desc expected actual + testCase desc $ actual @?= expected where desc = "192.168.0.0 in base-10 is 3232235520" expected = mk_testaddr 192 168 0 0 - actual = toEnum 3232235520 + -- We declare the big number as Word32 because otherwise, on x86, + -- we get a warning that it's too big to fit in a 32-bit integer. + -- Ultimately we convert it to a (negative) Int on those systems + -- anyway, but the gymnastics declare our intent to the compiler. + actual = toEnum (fromIntegral (3232235520 :: Word32)) :: IPv4Address + + +test_ord_instance1 :: TestTree +test_ord_instance1 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.0.0.1" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 0 0 1 + expected = True + actual = addr1 <= addr2 + + +test_ord_instance2 :: TestTree +test_ord_instance2 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.0.1.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 0 1 0 + expected = True + actual = addr1 <= addr2 + +test_ord_instance3 :: TestTree +test_ord_instance3 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 127.1.0.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 127 1 0 0 + expected = True + actual = addr1 <= addr2 + +test_ord_instance4 :: TestTree +test_ord_instance4 = + testCase desc $ actual @?= expected + where + desc = "127.0.0.0 is less than 128.0.0.0" + addr1 = mk_testaddr 127 0 0 0 + addr2 = mk_testaddr 128 0 0 0 + expected = True + actual = addr1 <= addr2