Move selection strategies to bitfield module

2 files changed, 74 insertions, 85 deletions

diff --git a/src/Network/BitTorrent/Exchange/Bitfield.hs b/src/Network/BitTorrent/Exchange/Bitfield.hs
index 3f4931f3..eca11d83 100644
--- a/src/Network/BitTorrent/Exchange/Bitfield.hs
+++ b/src/Network/BitTorrent/Exchange/Bitfield.hs
@@ -75,6 +75,17 @@ module Network.BitTorrent.Exchange.Bitfield
          -- * Serialization
        , fromBitmap
        , toBitmap
+
+         -- * Piece selection
+       , Selector
+       , selector
+       , strategyClass
+
+       , strictFirst
+       , strictLast
+       , rarestFirst
+       , randomFirst
+       , endGame
        ) where
 
 import Control.Monad
@@ -322,3 +333,66 @@ toBitmap Bitfield {..} = {-# SCC toBitmap #-} Lazy.fromChunks [intsetBM, alignme
     byteSize  = bfSize `div` 8 + if bfSize `mod` 8 == 0 then 0 else 1
     alignment = B.replicate (byteSize - B.length intsetBM) 0
     intsetBM  = S.toByteString bfSet
+
+{-----------------------------------------------------------------------
+--  Piece selection
+-----------------------------------------------------------------------}
+
+type Selector =  Bitfield      -- ^ Indices of client /have/ pieces.
+             ->  Bitfield      -- ^ Indices of peer /have/ pieces.
+             -> [Bitfield]     -- ^ Indices of other peers /have/ pieces.
+             -> Maybe PieceIx  -- ^ Zero-based index of piece to request
+                               --   to, if any.
+
+selector :: Selector       -- ^ Selector to use at the start.
+         -> 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 =
+  case strategyClass pt h of
+    SCBeginning -> start h a xs
+    SCReady     -> ready h a xs
+    SCEnd       -> endGame h a xs
+
+data StartegyClass
+  = SCBeginning
+  | SCReady
+  | SCEnd
+    deriving (Show, Eq, Ord, Enum, Bounded)
+
+
+strategyClass :: Ratio PieceCount -> Bitfield -> StartegyClass
+strategyClass threshold = classify . completeness
+  where
+    classify c
+      |        c < threshold       = SCBeginning
+      | c + 1 % numerator c < 1    = SCReady
+    -- FIXME numerator have is not total count
+      |          otherwise         = SCEnd
+
+
+-- | Select the first available piece.
+strictFirst :: Selector
+strictFirst h a _ = Just $ findMin (difference a h)
+
+-- | Select the last available piece.
+strictLast :: Selector
+strictLast h a _ = Just $ findMax (difference a h)
+
+-- |
+rarestFirst :: Selector
+rarestFirst h a xs = rarest (map (intersection want) xs)
+  where
+    want = difference h a
+
+-- | In average random first is faster than rarest first strategy but
+--    only if all pieces are available.
+randomFirst :: Selector
+randomFirst = do
+--  randomIO
+  error "randomFirst"
+
+endGame :: Selector
+endGame = strictLast
diff --git a/src/Network/BitTorrent/Exchange/Selection.hs b/src/Network/BitTorrent/Exchange/Selection.hs
deleted file mode 100644
index 3701450b..00000000
--- a/src/Network/BitTorrent/Exchange/Selection.hs
+++ /dev/null
@@ -1,85 +0,0 @@
--- |
---   Copyright   :  (c) Sam Truzjan 2013
---   License     :  BSD3
---   Maintainer  :  pxqr.sta@gmail.com
---   Stability   :  experimental
---   Portability :  portable
---
---   Piece selection algorithms.
---
-module Network.BitTorrent.Exchange.Selection
-       ( -- * Selection
-         Selector
-       , selector
-       , strategyClass
-
-       , strictFirst
-       , strictLast
-       , rarestFirst
-       , randomFirst
-       , endGame
-       ) where
-
-import Data.Ratio
-
-import Network.BitTorrent.Exchange.Bitfield
-
-
-type Selector =  Bitfield      -- ^ Indices of client /have/ pieces.
-             ->  Bitfield      -- ^ Indices of peer /have/ pieces.
-             -> [Bitfield]     -- ^ Indices of other peers /have/ pieces.
-             -> Maybe PieceIx  -- ^ Zero-based index of piece to request
-                               --   to, if any.
-
-selector :: Selector       -- ^ Selector to use at the start.
-         -> 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 =
-  case strategyClass pt h of
-    SCBeginning -> start h a xs
-    SCReady     -> ready h a xs
-    SCEnd       -> endGame h a xs
-
-data StartegyClass
-  = SCBeginning
-  | SCReady
-  | SCEnd
-    deriving (Show, Eq, Ord, Enum, Bounded)
-
-
-strategyClass :: Ratio PieceCount -> Bitfield -> StartegyClass
-strategyClass threshold = classify . completeness
-  where
-    classify c
-      |        c < threshold       = SCBeginning
-      | c + 1 % numerator c < 1    = SCReady
-    -- FIXME numerator have is not total count
-      |          otherwise         = SCEnd
-
-
--- | Select the first available piece.
-strictFirst :: Selector
-strictFirst h a _ = Just $ findMin (difference a h)
-
--- | Select the last available piece.
-strictLast :: Selector
-strictLast h a _ = Just $ findMax (difference a h)
-
--- |
-rarestFirst :: Selector
-rarestFirst h a xs = rarest (map (intersection want) xs)
-  where
-    want = difference h a
-
--- | In average random first is faster than rarest first strategy but
---    only if all pieces are available.
-randomFirst :: Selector
-randomFirst = do
---  randomIO
-  error "randomFirst"
-
-endGame :: Selector
-endGame = strictLast