BangPatterns
, FlexibleContexts
, ScopedTypeVariables
- , UnboxedTuples
, UnicodeSyntax
#-}
{-| This module provides entropy word encoding and decoding functions
where
import Codec.Audio.WavPack.Entropy
import Codec.Audio.WavPack.Internal
+import Control.Monad.Cont
+import Control.Monad.ST
+import Control.Monad.Trans
+import Control.Monad.Unicode
import Data.Bits
import Data.Bitstream.Generic (Bitstream)
import qualified Data.Bitstream.Generic as B
import Data.Int
-import qualified Data.Vector.Generic as GV
+import Data.STRef
import qualified Data.Vector.Generic.Mutable as MV
-import Data.Vector.Generic.New (New)
-import qualified Data.Vector.Generic.New as New
import Data.Word
+import Prelude hiding (break)
import Prelude.Unicode
-- | FIXME
-data WordsData
+data WordsData s
= WordsData {
- wdBitrateDelta ∷ !(Word32, Word32)
- , wdBitrateAcc ∷ !(Word32, Word32)
- , wdPendingData ∷ !Word32
- , wdHoldingOne ∷ !Word32
- , wdZeroesAcc ∷ !Word32
- , wdHoldingZero ∷ !Bool
- , wdPendingCount ∷ !Int
- , wdEntropyData ∷ !(EntropyData, EntropyData)
+ wdBitrateDelta ∷ !(STRef s (Word32, Word32))
+ , wdBitrateAcc ∷ !(STRef s (Word32, Word32))
+ , wdPendingData ∷ !(STRef s Word32)
+ , wdHoldingOne ∷ !(STRef s Word32)
+ , wdZeroesAcc ∷ !(STRef s Word32)
+ , wdHoldingZero ∷ !(STRef s Bool)
+ , wdPendingCount ∷ !(STRef s Int)
+ , wdEntropyData ∷ !(EntropyData s, EntropyData s)
}
- deriving (Eq, Show)
-- | This is an optimized version of 'getWord' that is used for
-- lossless only ('edErrorLimit' ≡ 0). Also, rather than obtaining a
-- single sample, it can be used to obtain an entire buffer of either
-- mono or stereo samples.
+getWordsLossless ∷ ∀bs v s. (Bitstream bs, MV.MVector v Int32)
+ ⇒ Bool -- ^ Is the stream monaural?
+ → WordsData s
+ → STRef s bs -- ^ WV bitstream
+ → Int -- ^ Number of samples to get
+ → ST s (v s Int32)
+{-# INLINEABLE getWordsLossless #-}
+getWordsLossless isMono w bs nSamples0
+ = do v ← MV.new nSamples
+ n ← runContT (for 0 (< nSamples) (+ 1) (loop v)) return
+ return $ MV.take n v
+ where
+ nSamples ∷ Int
+ nSamples = if isMono
+ then nSamples0
+ else nSamples0 ⋅ 2
+
+ loop ∷ v s Int32
+ → Int
+ → ContT Int (ST s) ()
+ → ContT Int (ST s) ()
+ → ContT Int (ST s) ()
+ loop v n break continue
+ = do let c | isMono = fst $ wdEntropyData w
+ | n `testBit` 0 = fst $ wdEntropyData w
+ | otherwise = snd $ wdEntropyData w
+ med00 ← lift $ readSTRef (edMedian0 $ fst $ wdEntropyData w)
+ hldZero ← lift $ readSTRef (wdHoldingZero w)
+ hldOne ← lift $ readSTRef (wdHoldingOne w)
+ med10 ← lift $ readSTRef (edMedian0 $ snd $ wdEntropyData w)
+ when (med00 < 2 ∧ hldZero ≡ False ∧ hldOne ≡ 0 ∧ med10 < 2) $
+ do zAcc ← lift $ readSTRef (wdZeroesAcc w)
+ if zAcc > 0 then
+ do lift $ modifySTRef (wdZeroesAcc w) ((-) 1)
+ when (zAcc > 1) $
+ do lift $ MV.unsafeWrite v n 0
+ continue
+ else
+ do cBits ← lift $ takeWhileLessThan id 33 bs
+
+ when (cBits ≡ 33) $
+ break
+
+ if cBits < 2 then
+ lift $ writeSTRef (wdZeroesAcc w) cBits
+ else
+ error "FIXME"
+ error "FIXME"
+
+{-
getWordsLossless ∷ ∀bs v. (Bitstream bs, GV.Vector v Int32)
⇒ Bool -- ^ Is the stream monaural?
→ WordsData
in
(# w1, bs1, v2 #)
where
- nSamples ∷ Int
- nSamples = if isMono
- then nSamples0
- else nSamples0 ⋅ 2
-
go0 ∷ WordsData → bs → Int → New v Int32
→ (# WordsData, bs, Int, New v Int32 #)
go0 w bs n v
let w' = w { wdZeroesAcc = wdZeroesAcc w - 1 }
in
if wdZeroesAcc w' > 0 then
- let v' = New.modify (\mv → MV.unsafeWrite mv n 0) v
- n' = n + 1
+ let (# n', v' #) = appendWord 0 n v
in
go0 w' bs n' v'
else
( clearMedian $ fst $ wdEntropyData w'
, clearMedian $ snd $ wdEntropyData w' )
}
- v' = New.modify (\mv → MV.unsafeWrite mv n 0) v
- n' = n + 1
+ (# n', v' #)
+ = appendWord 0 n v
in
go0 w'' bs'' n' v'
else
in
go2 0 w' bs n v
| otherwise
- = error "FIXME"
+ = let next8 ∷ Word8
+ next8 = B.toBits (B.take (8 ∷ Int) bs)
+ in
+ if next8 ≡ 0xFF then
+ error "FIXME"
+ else
+ error "FIXME"
go2 ∷ Word32 → WordsData → bs → Int → New v Int32
→ (# WordsData, bs, Int, New v Int32 #)
go2 0 w bs n v
= let ent = getEntropy n w
low = 0
- high = getMedian0 ent
+ high = getMedian0 ent - 1
ent' = decMedian0 ent
w' = setEntropy ent' n w
in
= let (# code, bs' #)
= readCode bs (high - low)
low' = low + code
- a = if B.head bs' then
+ word = if B.head bs' then
fromIntegral $ complement low'
else
fromIntegral low'
bs'' = B.tail bs'
- v' = New.modify (\mv → MV.unsafeWrite mv n a) v
- n' = n + 1
+ (# n', v' #)
+ = appendWord word n v
in
go0 w bs'' n' v'
+ appendWord ∷ Int32 → Int → New v Int32 → (# Int, New v Int32 #)
+ appendWord word n v
+ = let v' = New.modify (\mv → MV.unsafeWrite mv n word) v
+ n' = n + 1
+ in
+ (# n', v' #)
+
getEntropy ∷ Int → WordsData → EntropyData
getEntropy n w
| isMono = fst $ wdEntropyData w
| isMono = w { wdEntropyData = (e, snd $ wdEntropyData w) }
| n `testBit` 0 = w { wdEntropyData = (e, snd $ wdEntropyData w) }
| otherwise = w { wdEntropyData = (fst $ wdEntropyData w, e) }
+-}
-- | 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 #)
+readCode ∷ Bitstream bs ⇒ STRef s bs → Word32 → ST s Word32
{-# INLINEABLE readCode #-}
-readCode bs 0 = (# 0, bs #)
-readCode bs 1 = (# b2n (B.head bs), B.tail bs #)
+readCode bs 0 = return 0
+readCode bs 1 = fmap b2n $ takeHead bs
readCode bs maxCode
- = let !bitCount = countBits maxCode
- !extras = bit bitCount - maxCode - 1
- !code = B.toBits (B.take (bitCount - 1) bs)
- (# code', bitCount' #)
- = if code ≥ extras then
- (# (code `shiftL` 1)
- - extras
- + b2n (bs B.!! bitCount)
- , bitCount #)
+ = do let bitCount = countBits maxCode
+ extras = bit bitCount - maxCode - 1
+ code ← takeBits (bitCount - 1) bs
+ if code ≥ extras then
+ do nextBit ← takeHead bs
+ return $ (code `shiftL` 1) - extras + b2n nextBit
+ else
+ return code
+
+takeHead ∷ Bitstream bs ⇒ STRef s bs → ST s Bool
+{-# INLINEABLE takeHead #-}
+takeHead bsr
+ = do bs ← readSTRef bsr
+ writeSTRef bsr (B.tail bs)
+ return (B.head bs)
+
+takeWhileLessThan ∷ (Integral n, Bitstream bs)
+ ⇒ (Bool → Bool)
+ → n
+ → STRef s bs
+ → ST s n
+{-# INLINEABLE takeWhileLessThan #-}
+takeWhileLessThan f n bsr = go 0
+ where
+ {-# INLINE go #-}
+ go i | i < n
+ = do b ← takeHead bsr
+ if b then
+ go (i + 1)
else
- (# code, bitCount - 1 #)
- !bs' = B.drop bitCount' bs
- in
- (# code', bs' #)
+ return i
+ | otherwise
+ = return i
+
+takeBits ∷ (Integral n, Bitstream bs, Bits a) ⇒ n → STRef s bs → ST s a
+{-# INLINEABLE takeBits #-}
+takeBits n bsr
+ = do bs ← readSTRef bsr
+ writeSTRef bsr (B.drop n bs)
+ return (B.toBits (B.take n bs))
+
+-- | C style /for/ loop with /break/ and /continue/.
+for ∷ ∀m α. MonadCont m
+ ⇒ α -- ^ Initial state
+ → (α → Bool) -- ^ Continue-the-loop predicate
+ → (α → α) -- ^ State modifier
+ → (α → m () → m () → m ()) -- ^ Loop body taking breaker and
+ -- continuer
+ → m α -- ^ Final state
+for α0 contLoop next body
+ = callCC $ \break → loop break α0
+ where
+ loop ∷ (α → m ()) → α → m α
+ loop break α
+ | contLoop α
+ = do callCC $ \continue → body α (break α) (continue ())
+ loop break (next α)
+ | otherwise
+ = return α
projects / wavpack.git / blobdiff