Client.hsc

--------------------------------------------------------------------------------
-- |
-- Module    : Sound.ALSA.Sequencer.Marshal
-- Copyright : (c) Henning Thielemann, 2010
--             (c) Iavor S. Diatchki, 2007
-- License   : BSD3
--
-- Maintainer: Henning Thielemann
-- Stability : provisional
--
-- PRIVATE MODULE.
--
-- Here we have the various types used by the library,
-- and how they are imported\/exported to C.
--
-- NOTE: In the translations bellow we make the following assumptions
-- about the sizes of C types.
-- CChar  = 8 bits
-- CShort = 16 bit
-- CInt   = 32 bits
--------------------------------------------------------------------------------

module Sound.ALSA.Sequencer.Marshal.Client where

#include <alsa/asoundlib.h>
import qualified Sound.ALSA.Sequencer.Utility as U
import Foreign.C.Types (CInt, )
import Foreign.Storable (Storable, )
import Data.Word (Word8, )


-- | The type of client identifiers.
newtype T = Cons Word8 deriving (Eq, Ord, Storable)

instance Show T where
   showsPrec prec (Cons x) =
      U.showsRecord prec "Client" [U.showsField x]


#{enum T, Cons
 , system      = SND_SEQ_CLIENT_SYSTEM
 , subscribers = SND_SEQ_ADDRESS_SUBSCRIBERS
 , broadcast   = SND_SEQ_ADDRESS_BROADCAST
 , unknown     = SND_SEQ_ADDRESS_UNKNOWN
 }



exp :: T -> CInt
exp (Cons c) = fromIntegral c

imp :: CInt -> T
imp p = Cons (fromIntegral p)

-- | The different types of clients.
data Type = User | Kernel

impType :: CInt -> Type
impType x =
   if x == #{const SND_SEQ_USER_CLIENT}
     then User
     else Kernel