--- Read a single unsigned value from the specified bitstream with a
--- value from 0 to maxCode. If there are exactly a power of two number
--- of possible codes then this will read a fixed number of bits;
--- otherwise it reads the minimum number of bits and then determines
--- whether another bit is needed to define the code.
-readCode ∷ Bitstream bs ⇒ bs → Word32 → (Word32, bs)
-{-# INLINEABLE readCode #-}
-readCode bs 0 = (0, bs)
-readCode bs 1 = (b2n $ B.head bs, B.tail bs)
-readCode bs maxCode
- = let !bitCount = countBits maxCode
- !extras = (1 `shiftL` bitCount) - maxCode - 1
- in
- error "unk"
\ No newline at end of file
+-- | FIXME
+data WavpackStream s
+ = WavpackStream {
+ wpsHeader ∷ !BlockHeader
+ , wpsMuteError ∷ !(STRef s Bool)
+ , wpsSampleIndex ∷ !(STRef s Word32)
+ }
+
+-- |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 ∷ ∀v s. (MV.MVector v Int32)
+ ⇒ WavpackStream 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 = wpsHeader wps
+ flags = bhFlags hdr
+ 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
+ error "FIXME"