Adding unsafeCreate to allow for deserialization of Bloom filters.

Data/BloomFilter.hs

@@ -70,6 +70,8 @@ module Data.BloomFilter
 
     -- | The raw bit array used by the immutable 'Bloom' type.
     , bitArray
+    , serialize
+    , unsafeDeserialize
     ) where
 
 import Control.Monad (liftM, forM_)
@@ -85,6 +87,9 @@ import qualified Data.BloomFilter.Mutable.Internal as MB
 import Data.BloomFilter.Mutable.Internal (Hash, MBloom)
 import Data.Word (Word32)
 
+import Data.Serialize
+import Data.ByteString (ByteString)
+
 import Prelude hiding (elem, length, notElem,
                        (/), (*), div, divMod, mod, rem)
 
@@ -320,6 +325,21 @@ logPower2 k = go 0 k
     where go j 1 = j
           go j n = go (j+1) (n `shiftR` 1)
 
+serialize :: Bloom a -> ByteString
+serialize bloom = encode (shift bloom, mask bloom, bitArray bloom)
+
+unsafeDeserialize :: (a -> [Hash]) -> ByteString -> Either String (Bloom a)
+unsafeDeserialize hashes bs =
+  case decode bs of
+    Left err -> Left err
+    Right (shift, mask, bitArray) -> Right $ B
+      { hashes = hashes
+      , shift = shift
+      , mask = mask
+      , bitArray = bitArray
+      }
+
+
 -- $overview
 --
 -- Each of the functions for creating Bloom filters accepts two parameters:

bloomfilter.cabal

@@ -20,6 +20,7 @@ library
     array,
     base       >= 4.4 && < 5,
     bytestring >= 0.9,
+    cereal >= 0.4,
     deepseq
   exposed-modules:  Data.BloomFilter
                     Data.BloomFilter.Easy