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{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE OverloadedStrings #-}
module Network.BitTorrent.PeerWire.Block
( BlockIx(..)
, Block(..), blockSize
, PieceIx
, BlockLIx, PieceLIx
, defaultBlockSize
, pieceIx, blockIx
, blockRange, ixRange, isPiece
, ppBlockIx, ppBlock
, putInt, getInt
) where
import Control.Applicative
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import Data.Int
import Data.Serialize
import Text.PrettyPrint
type BlockLIx = Int
type PieceLIx = Int
type PieceIx = Int
data BlockIx = BlockIx {
-- | Zero-based piece index.
ixPiece :: {-# UNPACK #-} !PieceLIx
-- | Zero-based byte offset within the piece.
, ixOffset :: {-# UNPACK #-} !Int
-- | Block size starting from offset.
, ixLength :: {-# UNPACK #-} !Int
} deriving (Show, Eq)
getInt :: Get Int
getInt = fromIntegral <$> getWord32be
{-# INLINE getInt #-}
putInt :: Putter Int
putInt = putWord32be . fromIntegral
{-# INLINE putInt #-}
instance Serialize BlockIx where
{-# SPECIALIZE instance Serialize BlockIx #-}
get = BlockIx <$> getInt <*> getInt <*> getInt
{-# INLINE get #-}
put ix = do putInt (ixPiece ix)
putInt (ixOffset ix)
putInt (ixLength ix)
{-# INLINE put #-}
ppBlockIx :: BlockIx -> Doc
ppBlockIx BlockIx {..} =
"piece = " <> int ixPiece <> "," <+>
"offset = " <> int ixOffset <> "," <+>
"length = " <> int ixLength
data Block = Block {
-- | Zero-based piece index.
blkPiece :: PieceLIx
-- | Zero-based byte offset within the piece.
, blkOffset :: Int
-- | Payload.
, blkData :: ByteString
} deriving (Show, Eq)
ppBlock :: Block -> Doc
ppBlock = ppBlockIx . blockIx
blockSize :: Block -> Int
blockSize blk = B.length (blkData blk)
-- | Widely used semi-official block size.
defaultBlockSize :: Int
defaultBlockSize = 16 * 1024
isPiece :: Int -> Block -> Bool
isPiece pieceSize (Block i offset bs) =
offset == 0 && B.length bs == pieceSize && i >= 0
{-# INLINE isPiece #-}
pieceIx :: Int -> Int -> BlockIx
pieceIx i = BlockIx i 0
{-# INLINE pieceIx #-}
blockIx :: Block -> BlockIx
blockIx = BlockIx <$> blkPiece <*> blkOffset <*> B.length . blkData
blockRange :: (Num a, Integral a) => Int -> Block -> (a, a)
blockRange pieceSize blk = (offset, offset + len)
where
offset = fromIntegral pieceSize * fromIntegral (blkPiece blk)
+ fromIntegral (blkOffset blk)
len = fromIntegral (B.length (blkData blk))
{-# INLINE blockRange #-}
{-# SPECIALIZE blockRange :: Int -> Block -> (Int64, Int64) #-}
ixRange :: (Num a, Integral a) => Int -> BlockIx -> (a, a)
ixRange pieceSize ix = (offset, offset + len)
where
offset = fromIntegral pieceSize * fromIntegral (ixPiece ix)
+ fromIntegral (ixOffset ix)
len = fromIntegral (ixLength ix)
{-# INLINE ixRange #-}
{-# SPECIALIZE ixRange :: Int -> BlockIx -> (Int64, Int64) #-}
|
