~ Use IntSet instead of ByteString for bitfields.

There are several reasons for this:

* IntSet is stored in ordinary heap, while ByteStrings in pinned memory;
* Our IntSet's should be much faster 90% time. (in typical BT client)
  Hovewer in worst case IntSet is slower, but difference should is not
  so big. (We should measure this although)
* It's pure, tested, error-free and much more convenient.

Moreover we have kill a lot of ugly code!

2 files changed, 18 insertions, 22 deletions

diff --git a/src/Network/BitTorrent/PeerWire/Message.hs b/src/Network/BitTorrent/PeerWire/Message.hs
index 5544dca7..f5ad2693 100644
--- a/src/Network/BitTorrent/PeerWire/Message.hs
+++ b/src/Network/BitTorrent/PeerWire/Message.hs
@@ -28,27 +28,27 @@ data Message = KeepAlive
 
                -- | Zero-based index of a piece that has just been
                -- successfully downloaded and verified via the hash.
-             | Have     PieceIx
+             | Have     !PieceIx
 
                -- | The bitfield message may only be sent immediately
                -- after the handshaking sequence is complete, and
                -- before any other message are sent. If client have no
                -- pieces then bitfield need not to be sent.
-             | Bitfield Bitfield
+             | Bitfield !Bitfield
 
                -- | Request for a particular block. If a client is
                -- requested a block that another peer do not have the
                -- peer might not answer at all.
-             | Request  BlockIx
+             | Request  !BlockIx
 
                -- | Response for a request for a block.
-             | Piece    Block
+             | Piece    !Block
 
                -- | Used to cancel block requests. It is typically
                -- used during "End Game".
-             | Cancel   BlockIx
+             | Cancel   !BlockIx
 
-             | Port     PortNumber
+             | Port     !PortNumber
 
                -- | BEP 6: Then peer have all pieces it might send the
                --   'HaveAll' message instead of 'Bitfield'
@@ -63,16 +63,16 @@ data Message = KeepAlive
                -- | BEP 6: This is an advisory message meaning "you
                -- might like to download this piece." Used to avoid
                -- excessive disk seeks and amount of IO.
-             | SuggestPiece PieceIx
+             | SuggestPiece !PieceIx
 
                -- | BEP 6: Notifies a requesting peer that its request
                -- will not be satisfied.
-             | RejectRequest BlockIx
+             | RejectRequest !BlockIx
 
                -- | BEP 6: This is an advisory messsage meaning "if
                -- you ask for this piece, I'll give it to you even if
                -- you're choked." Used to shorten starting phase.
-             | AllowedFast PieceIx
+             | AllowedFast !PieceIx
                deriving (Show, Eq)
 
 
diff --git a/src/Network/BitTorrent/PeerWire/Selection.hs b/src/Network/BitTorrent/PeerWire/Selection.hs
index 9d154613..63cca15d 100644
--- a/src/Network/BitTorrent/PeerWire/Selection.hs
+++ b/src/Network/BitTorrent/PeerWire/Selection.hs
@@ -33,6 +33,7 @@ module Network.BitTorrent.PeerWire.Selection
        ) where
 
 import Data.Bitfield
+import Data.Ratio
 import Network.BitTorrent.PeerWire.Block
 
 
@@ -42,10 +43,8 @@ type Selector =  Bitfield      -- ^ Indices of client /have/ pieces.
              -> Maybe PieceIx  -- ^ Zero-based index of piece to request
                                --   to, if any.
 
-type PieceThreshold = Int
-
 selector :: Selector       -- ^ Selector to use at the start.
-         -> PieceThreshold
+         -> Ratio PieceCount
          -> Selector       -- ^ Selector to use after the client have the C pieces.
          -> Selector       -- ^ Selector that changes behaviour based on completeness.
 selector start pt ready   h a xs =
@@ -60,16 +59,14 @@ data StartegyClass
   | SCEnd
     deriving (Show, Eq, Ord, Enum, Bounded)
 
-endThreshold :: PieceThreshold
-endThreshold = 1
 
-strategyClass :: PieceThreshold -> Bitfield -> StartegyClass
-strategyClass pt = classify . completeness
+strategyClass :: Ratio PieceCount -> Bitfield -> StartegyClass
+strategyClass threshold = classify . completeness
   where
-    classify (have, total)
-      | have < pt                   = SCBeginning
-      | total - have > endThreshold = SCReady
-      | otherwise                   = SCEnd
+    classify have
+      |          have < threshold     = SCBeginning
+      | have + 1 % numerator have < 1 = SCReady -- FIXME numerator have is not total count
+      |           otherwise           = SCEnd
 
 
 -- | Select the first available piece.
@@ -82,10 +79,9 @@ strictLast h a _ = findMax (difference a h)
 
 -- |
 rarestFirst :: Selector
-rarestFirst h a xs = rarest (frequencies (map (intersection want) xs))
+rarestFirst h a xs = rarest (map (intersection want) xs)
   where
     want = difference h a
-    rarest = Just . head
 
 -- | In average random first is faster than rarest first strategy but
 --    only if all pieces are available.