Moved the maskable instance definitions within their corresponding modules.

[hath.git] / src / Octet.hs

diff --git a/src/Octet.hs b/src/Octet.hs
index b3e6a0f5d3c1310f38443ca99dc49c43de516e5a..ceeb4b8ff2ddd9e3c047ab78924f7f7b206d6ef8 100644 (file)
--- a/src/Octet.hs
+++ b/src/Octet.hs
@@ -3,7 +3,9 @@ module Octet where
 import Test.HUnit
 import Test.QuickCheck
 
-import Bit
+import Bit as B
+import Maskable
+import 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
@@ -39,6 +41,22 @@ instance Arbitrary Octet where
     coarbitrary _ = variant 0
 
 
+instance Maskable Octet where
+    apply_mask _ Maskbits.None = Octet.None
+    apply_mask Octet.None _    = Octet.None
+    apply_mask oct mask
+        | mask == Eight = oct
+        | mask == Seven = oct { b8 = B.Zero }
+        | mask == Six = oct { b8 = B.Zero, b7 = B.Zero }
+        | mask == Five = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero }
+        | mask == Four = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero }
+        | mask == Three = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero }
+        | mask == Two = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero, b3 = B.Zero }
+        | mask == Maskbits.One = oct { b8 = B.Zero, b7 = B.Zero, b6 = B.Zero, b5 = B.Zero, b4 = B.Zero, b3 = B.Zero, b2 = B.Zero }
+        | mask == Maskbits.Zero = min_octet
+        | otherwise = Octet.None
+
+
 -- 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.
@@ -60,14 +78,14 @@ 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
+      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
 
 
 octet_from_string :: String -> Octet
@@ -79,12 +97,12 @@ octet_from_string s =
 
 -- The octet with the least possible value.
 min_octet :: Octet
-min_octet = Octet Zero Zero Zero Zero Zero Zero Zero Zero
+min_octet = Octet B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
 
 
 -- The octet with the greatest possible value.
 max_octet :: Octet
-max_octet = Octet One One One One One One One One
+max_octet = Octet B.One B.One B.One B.One B.One B.One B.One B.One
 
 
 
@@ -93,8 +111,26 @@ test_octet_from_int1 :: Test
 test_octet_from_int1 =
     TestCase $ assertEqual "octet_from_int 128 should parse as 10000000" oct1 (octet_from_int 128)
     where
-      oct1 = Octet One Zero Zero Zero Zero Zero Zero Zero
+      oct1 = Octet B.One B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero B.Zero
+
+
+test_octet_mask1 :: Test
+test_octet_mask1 =
+    TestCase $ assertEqual "The network bits of 255/4 should equal 240" oct2 (apply_mask oct1 Four)
+    where
+      oct1 = octet_from_int 255
+      oct2 = octet_from_int 240
+
+
+test_octet_mask2 :: Test
+test_octet_mask2 =
+    TestCase $ assertEqual "The network bits of 255/1 should equal 128" oct2 (apply_mask oct1 Maskbits.One)
+    where
+      oct1 = octet_from_int 255
+      oct2 = octet_from_int 128
 
 
 octet_tests :: [Test]
-octet_tests = [ test_octet_from_int1 ]
+octet_tests = [ test_octet_from_int1,
+                test_octet_mask1,
+                test_octet_mask2 ]