-- |Partial binding to CoreAudio, as required for `System.MIDI`. 
-- At the moment only HostTime is supported. 
-- In the future this module should grow into a separate entity.

{-# LANGUAGE ForeignFunctionInterface #-}
module System.MacOSX.CoreAudio 
  ( audioGetCurrentHostTime
  , audioConvertHostTimeToNanos
  , audioConvertNanosToHostTime
  , audioGetCurrentTimeInNanos
  )
  where

import System.MacOSX.CoreFoundation

foreign import ccall unsafe "HostTime.h AudioGetCurrentHostTime"
  audioGetCurrentHostTime :: IO UInt64
  
foreign import ccall unsafe "HostTime.h AudioConvertHostTimeToNanos" 
  audioConvertHostTimeToNanos :: UInt64 -> IO UInt64 
  
foreign import ccall unsafe "HostTime.h AudioConvertNanosToHostTime" 
  audioConvertNanosToHostTime :: UInt64 -> IO UInt64 

audioGetCurrentTimeInNanos :: IO UInt64  
audioGetCurrentTimeInNanos = ( audioGetCurrentHostTime >>= audioConvertHostTimeToNanos )