Cut.hs

module Synthesizer.Storable.Cut where

import qualified Synthesizer.Storable.Signal as Sig

import qualified Data.EventList.Relative.TimeBody as EventList
import Control.Monad.State (runState, modify, gets, put, )
import Synthesizer.Utility (mapSnd, )

-- import qualified Algebra.Real     as Real
import qualified Algebra.Additive as Additive
import qualified Number.NonNegative as NonNeg

import Foreign.Storable (Storable)

import PreludeBase
import NumericPrelude


{-# INLINE arrange #-}
arrange :: (Storable v, Additive.C v) =>
       Sig.ChunkSize
    -> EventList.T NonNeg.Int (Sig.T v)
            {-^ A list of pairs: (relative start time, signal part),
                The start time is relative to the start time
                of the previous event. -}
    -> Sig.T v
            {-^ The mixed signal. -}
arrange size =
   uncurry Sig.append .
   flip runState Sig.empty .
   fmap (Sig.concat . EventList.getTimes) .
   EventList.mapM
      (\timeNN ->
           let time = NonNeg.toNumber timeNN
           in  do (prefix,suffix) <- gets (Sig.splitAtPad size time)
                  put suffix
                  return prefix)
      (\body ->
           modify (Sig.mix body))


arrangeList :: (Storable v, Additive.C v) =>
       Sig.ChunkSize
    -> EventList.T NonNeg.Int (Sig.T v)
            {-^ A list of pairs: (relative start time, signal part),
                The start time is relative to the start time
                of the previous event. -}
    -> Sig.T v
            {-^ The mixed signal. -}
arrangeList size evs =
   let xs = EventList.getBodies evs
   in  case EventList.getTimes evs of
          t:ts -> Sig.replicate size (NonNeg.toNumber t) zero `Sig.append`
                  addShiftedMany size ts xs
          []   -> Sig.empty


addShiftedMany :: (Storable a, Additive.C a) =>
   Sig.ChunkSize -> [NonNeg.Int] -> [Sig.T a] -> Sig.T a
addShiftedMany size ds xss =
   foldr (uncurry (addShifted size)) Sig.empty (zip (ds++[0]) xss)


{-
It is crucial that 'mix' uses the chunk size structure of the second operand.
This way we avoid unnecessary and even infinite look-ahead.
-}
addShifted :: (Storable a, Additive.C a) =>
   Sig.ChunkSize -> NonNeg.Int -> Sig.T a -> Sig.T a -> Sig.T a
addShifted size delNN px py =
   let del = NonNeg.toNumber delNN
   in  uncurry Sig.append $
       mapSnd (flip Sig.mix py) $
       Sig.splitAtPad size del px