29 lines
805 B
Haskell
29 lines
805 B
Haskell
module Network.TLS.Util
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( sub
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, takelast
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, partition6
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) where
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import Network.TLS.Struct (Bytes)
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import Network.TLS.Wire
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import qualified Data.ByteString as B
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sub :: Bytes -> Int -> Int -> Maybe Bytes
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sub b offset len
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| B.length b < offset + len = Nothing
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| otherwise = Just $ B.take len $ snd $ B.splitAt offset b
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takelast :: Int -> Bytes -> Maybe Bytes
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takelast i b
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| B.length b >= i = sub b (B.length b - i) i
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| otherwise = Nothing
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partition6 :: Bytes -> (Int,Int,Int,Int,Int,Int) -> Maybe (Bytes, Bytes, Bytes, Bytes, Bytes, Bytes)
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partition6 bytes (d1,d2,d3,d4,d5,d6) = either (const Nothing) Just $ (flip runGet) bytes $ do
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p1 <- getBytes d1
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p2 <- getBytes d2
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p3 <- getBytes d3
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p4 <- getBytes d4
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p5 <- getBytes d5
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p6 <- getBytes d6
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return (p1,p2,p3,p4,p5,p6)
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