Controller (partway)

[EsounD.git] / Sound / EsounD / Internals.hs

diff --git a/Sound/EsounD/Internals.hs b/Sound/EsounD/Internals.hs
index 4f57a3b07e694772fc507bd2590041311411e73b..f4b067f0903cf30fc9a23b62ccb13dee41c5e4fe 100644 (file)
--- a/Sound/EsounD/Internals.hs
+++ b/Sound/EsounD/Internals.hs
@@ -1,5 +1,7 @@
 {-# LANGUAGE
     EmptyDataDecls
+  , FlexibleInstances
+  , MultiParamTypeClasses
   , UnicodeSyntax
   #-}
 module Sound.EsounD.Internals
@@ -8,18 +10,25 @@ module Sound.EsounD.Internals
     , Channels(..)
     , Mono
     , Stereo
+    , interleave
+    , deinterleave
 
+    , toLSV
     , wrapSocket
     , closeSocket
     , withCStrOrNull
+    , failOnError
     )
     where
 import Bindings.EsounD
 import Data.Int
+import Data.StorableVector      as S
+import Data.StorableVector.Lazy as L
 import Foreign.C.String
 import Foreign.C.Types
 import Foreign.Ptr
 import Foreign.Storable
+import Prelude.Unicode
 import System.IO
 import System.Posix.IO
 import System.Posix.Types
@@ -36,14 +45,47 @@ instance Frame Int16 where
 class Channels ch where
     channelFmt ∷ ch → C'esd_format_t
 
+-- Mono
 data Mono
+
 instance Channels Mono where
     channelFmt _ = c'ESD_MONO
 
+-- Stereo
 data Stereo
+
 instance Channels Stereo where
     channelFmt _ = c'ESD_STEREO
 
+{-# INLINE interleave #-}
+interleave ∷ Storable α ⇒ L.Vector α → L.Vector α → L.Vector α
+interleave l r
+    -- THINKME: consider using storablevector-streamfusion
+    = let Just (lFr, l') = L.viewL l
+          Just (rFr, r') = L.viewL r
+          lr' = interleave l' r'
+      in
+        L.cons lFr (L.cons rFr lr')
+
+{-# INLINE deinterleave #-}
+deinterleave ∷ Storable α ⇒ L.Vector α → (L.Vector α, L.Vector α)
+deinterleave v
+    -- THINKME: consider using storablevector-streamfusion
+    = let (lr, v') = L.splitAt 2 v
+      in
+        if L.null lr then
+            (L.empty, L.empty)
+        else
+            let Just (lFr, r) = L.viewL lr
+                Just (rFr, _) = L.viewL r
+                (l', r') = deinterleave v'
+            in
+              (L.cons lFr l', L.cons rFr r')
+
+-- Utility functions
+toLSV ∷ Storable α ⇒ S.Vector α → L.Vector α
+toLSV v = L.fromChunks [v]
+
 wrapSocket ∷ String → CInt → IO Handle
 wrapSocket e (-1) = fail e
 wrapSocket _ fd   = fdToHandle (Fd fd)
@@ -56,3 +98,8 @@ closeSocket h = do (Fd fd) ← handleToFd h
 withCStrOrNull ∷ Maybe String → (CString → IO a) → IO a
 withCStrOrNull Nothing  f = f nullPtr
 withCStrOrNull (Just s) f = withCString s f
+
+failOnError ∷ Monad m ⇒ String → CInt → m ()
+failOnError msg rv
+    | rv ≤ 0   = fail msg
+    | otherwise = return ()