NetReader.hs

module SSH.NetReader where

import Control.Monad.Trans.State (State, gets, modify)
import Data.Binary (decode)
import Data.Int (Int32)
import Data.Word (Word8, Word32)
import qualified Data.ByteString.Lazy as LBS

import SSH.Packet (unmpint)
import SSH.Util (fromLBS)


type NetReader = State LBS.ByteString


readByte :: NetReader Word8
readByte = fmap LBS.head (readBytes 1)

readLong :: NetReader Int32
readLong = fmap decode (readBytes 4)

readULong :: NetReader Word32
readULong = fmap decode (readBytes 4)

readInteger :: NetReader Integer
readInteger = do
    len <- readULong
    b <- readBytes (fromIntegral len)
    return (unmpint b)

readBytes :: Int -> NetReader LBS.ByteString
readBytes n = do
    p <- gets (LBS.take (fromIntegral n))
    modify (LBS.drop (fromIntegral n))
    return p

readLBS :: NetReader LBS.ByteString
readLBS = readULong >>= readBytes . fromIntegral

readString :: NetReader String
readString = fmap fromLBS readLBS

readBool :: NetReader Bool
readBool = readByte >>= return . (== 1)