+{-# LANGUAGE
+ DoAndIfThenElse
+ , FlexibleContexts
+ , ScopedTypeVariables
+ , UnicodeSyntax
+ #-}
module Codec.Audio.WavPack.Unpack
- (
+ ( WavpackStream(..)
+ , unpackSamples
)
where
+import Codec.Audio.WavPack.Block
+import Codec.Audio.WavPack.Words
+import Control.Monad.ST
+import Data.Bits
+import Data.Bitstream.Generic (Bitstream)
+import Data.Int
+import Data.STRef
+import qualified Data.Strict as S
+import qualified Data.Vector.Generic.Mutable as MV
+import Data.Word
+import Prelude.Unicode
+
+-- | FIXME
+data WavpackStream bs s
+ = WavpackStream {
+ wpsWVBlock ∷ !Block
+ , wpsWVCBlock ∷ !(S.Maybe Block)
+ , wpsWordsData ∷ !(WordsData s)
+ , wpsMuteError ∷ !(STRef s Bool)
+ , wpsSampleIndex ∷ !(STRef s Word32)
+ , wpsWVBits ∷ !(STRef s bs)
+ , wpsWVCBits ∷ !(S.Maybe (STRef s bs))
+ }
+
+-- |This monster actually unpacks the WavPack bitstream(s) into the
+-- specified buffer as 32-bit integers or floats (depending on orignal
+-- data). Lossy samples will be clipped to their original limits
+-- (i.e. 8-bit samples are clipped to -128/+127) but are still
+-- returned in longs. It is up to the caller to potentially reformat
+-- this for the final output including any multichannel distribution,
+-- block alignment or endian compensation.
+unpackSamples ∷ ∀bs v s. (Bitstream bs, MV.MVector v Int32)
+ ⇒ WavpackStream bs s
+ → Int -- ^ Number of channels.
+ → Int -- ^ Reduced number of channels (1 or 2).
+ → Word32 -- ^ Number of samples to get.
+ → ST s (v s Int32)
+{-# INLINEABLE unpackSamples #-}
+unpackSamples wps numChannels reducedChannels nSamples0
+ = do let hdr = blockHeader $ wpsWVBlock wps
+ flags = bhFlags hdr
+ muteLimit0 = (1 `shiftL` fromIntegral (bfMaxMagnitude flags)) + 2
+ muteLimit ∷ Int32 -- FIXME: Do we really need to explicitly type this?
+ muteLimit
+ | bfHybrid flags ∧ S.isNothing (wpsWVCBlock wps)
+ = muteLimit0 ⋅ 2
+ | otherwise
+ = muteLimit0
+
+ nSamples ← do idx ← readSTRef (wpsSampleIndex wps)
+ if idx + nSamples0 > bhBlockIndex hdr + bhBlockSamples hdr then
+ return $ bhBlockIndex hdr + bhBlockSamples hdr - idx
+ else
+ return nSamples0
+
+ muteError ← readSTRef (wpsMuteError wps)
+ if muteError then
+ do v ← if reducedChannels ≡ 1 ∨ numChannels ≡ 1 ∨ bfMono flags then
+ MV.replicate (fromIntegral nSamples) 0
+ else
+ MV.replicate (fromIntegral nSamples ⋅ 2) 0
+ modifySTRef (wpsSampleIndex wps) (+ nSamples)
+ return v
+ else
+ do v ← if S.isNothing (wpsWVCBlock wps) ∧ bfMono flags then
+ -- handle lossless or hybrid lossy mono data
+ fail "FIXME: unsupported stream type: monaural stream"
+ else
+ if S.isNothing (wpsWVCBlock wps) ∧ (¬) (bfMono flags) then
+ -- handle lossless or hybrid lossy stereo data
+ do v ← if bfHybrid flags then
+ fail "FIXME: unsupported stream type: lossy stereo stream"
+ else
+ getWordsLossless
+ (bfMono flags)
+ (wpsWordsData wps)
+ (wpsWVBits wps)
+ nSamples
+ error "FIXME"
+ return v
+ else
+ error "FIXME"
+ error "FIXME"
+ return v