Made bits-extras dependency optional.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/Data/Torrent.hs b/src/Data/Torrent.hs
index d6f141a8..6bec665e 100644
--- a/src/Data/Torrent.hs
+++ b/src/Data/Torrent.hs
@@ -154,7 +154,9 @@ import Crypto.Hash.SHA1 as SHA1
 import Data.BEncode as BE
 import Data.BEncode.Types as BE
 import Data.Bits
+#ifdef VERSION_bits_extras
 import Data.Bits.Extras
+#endif
 import Data.ByteString as BS
 import Data.ByteString.Base16 as Base16
 import Data.ByteString.Base32 as Base32
@@ -584,7 +586,11 @@ maxPieceSize = 4 * 1024 * 1024
 {-# INLINE maxPieceSize #-}
 
 toPow2 :: Int -> Int
+#ifdef VERSION_bits_extras
 toPow2 x = bit $ fromIntegral (leadingZeros (0 :: Int) - leadingZeros x)
+#else
+toPow2 x = bit $ fromIntegral (countLeadingZeros (0 :: Int) - countLeadingZeros x)
+#endif
 
 -- | Find the optimal piece size for a given torrent size.
 defaultPieceSize :: Int64 -> Int