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|
-- |
-- Copyright : (c) Sam T. 2013
-- License : MIT
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- This module provides peer capabilities detection.
--
-- See <http://www.bittorrent.org/beps/bep_0004.html> for more
-- information.
--
{-# LANGUAGE OverloadedStrings #-}
module Network.BitTorrent.Extension
( Capabilities, ppCaps, defaultCaps, enabledCaps
, Extension(..), ppExtension, encodeExts, decodeExts
) where
import Data.Bits
import Data.Word
import Text.PrettyPrint
type Capabilities = Word64
ppCaps :: Capabilities -> Doc
ppCaps = hcat . punctuate ", " . map ppExtension . decodeExts
defaultCaps :: Capabilities
defaultCaps = 0
enabledCaps :: Capabilities -- ^ of the client.
-> Capabilities -- ^ of the peer.
-> Capabilities -- ^ should be considered as enabled.
enabledCaps = (.&.)
data Extension = ExtDHT -- ^ BEP 5
| ExtFast -- ^ BEP 6
deriving (Show, Eq, Ord, Enum, Bounded)
ppExtension :: Extension -> Doc
ppExtension ExtDHT = "DHT"
ppExtension ExtFast = "Fast Extension"
extensionMask :: Extension -> Word64
extensionMask ExtDHT = 0x01
extensionMask ExtFast = 0x04
encodeExts :: [Extension] -> Capabilities
encodeExts = foldr (.&.) 0 . map extensionMask
decodeExts :: Capabilities -> [Extension]
decodeExts rb = filter (testMask rb . extensionMask) [minBound..maxBound]
where
testMask bits x = bits .&. x > 0
|
