EntropyData s

[wavpack.git] / Codec / Audio / WavPack / Entropy.hs

diff --git a/Codec/Audio/WavPack/Entropy.hs b/Codec/Audio/WavPack/Entropy.hs
index f031d118d112342b25bf005b2e13234a04d0a502..e7468017de69f6662b3932ce9b6ad7c1a36e566a 100644 (file)
--- a/Codec/Audio/WavPack/Entropy.hs
+++ b/Codec/Audio/WavPack/Entropy.hs
@@ -19,31 +19,31 @@ module Codec.Audio.WavPack.Entropy
     , decMedian2
     )
     where
+import Control.Monad.ST
+import Control.Monad.Unicode
 import Data.Bits
+import Data.STRef
 import Data.Word
 import Prelude.Unicode
 
 -- | FIXME
-data EntropyData
+data EntropyData s
     = EntropyData {
         -- | Median log2 values for a channel.
-        edMedian0    ∷ !Word32
-      , edMedian1    ∷ !Word32
-      , edMedian2    ∷ !Word32
+        edMedian0    ∷ !(STRef s Word32)
+      , edMedian1    ∷ !(STRef s Word32)
+      , edMedian2    ∷ !(STRef s Word32)
         -- | FIXME
-      , edSlowLevel  ∷ !Word32
+      , edSlowLevel  ∷ !(STRef s Word32)
         -- | FIXME
-      , edErrorLimit ∷ !Word32
+      , edErrorLimit ∷ !(STRef s Word32)
       }
-    deriving (Eq, Show)
 
-clearMedian ∷ EntropyData → EntropyData
-{-# INLINE clearMedian #-}
-clearMedian e = e {
-                  edMedian0 = 0
-                , edMedian1 = 0
-                , edMedian2 = 0
-                }
+clearMedian ∷ EntropyData s → ST s ()
+clearMedian e
+    = writeSTRef (edMedian0 e) 0 ≫
+      writeSTRef (edMedian1 e) 0 ≫
+      writeSTRef (edMedian2 e) 0
 
 -- | The time constant of the 3 median level breakpoints
 div0, div1, div2 ∷ Word32
@@ -52,35 +52,20 @@ div1 =  64 -- 10/ 49 of samples
 div2 =  32 -- 20/343 of samples
 
 -- | Retrieve the specified median breakpoint (without frac; min = 1)
-getMedian0, getMedian1, getMedian2 ∷ EntropyData → Word32
-{-# INLINE getMedian0 #-}
-{-# INLINE getMedian1 #-}
-{-# INLINE getMedian2 #-}
-getMedian0 e = (edMedian0 e `shiftR` 4) + 1
-getMedian1 e = (edMedian1 e `shiftR` 4) + 1
-getMedian2 e = (edMedian2 e `shiftR` 4) + 1
+getMedian0, getMedian1, getMedian2 ∷ EntropyData s → ST s Word32
+getMedian0 = fmap ((`shiftR` 4) ∘ (+ 1)) ∘ readSTRef ∘ edMedian0
+getMedian1 = fmap ((`shiftR` 4) ∘ (+ 1)) ∘ readSTRef ∘ edMedian1
+getMedian2 = fmap ((`shiftR` 4) ∘ (+ 1)) ∘ readSTRef ∘ edMedian2
 
 -- | Update the specified median breakpoints. Note that the median is
 -- incremented when the sample is higher than the median, else
 -- decremented.  They are designed so that the median will never drop
 -- below 1 and the value is essentially stationary if there are 2
 -- increments for every 5 decrements.
-incMedian0, decMedian0, incMedian1, decMedian1, incMedian2, decMedian2 ∷ EntropyData → EntropyData
-incMedian0 e
-    = e { edMedian0 =
-              edMedian0 e + ((edMedian0 e +  div0   ) `div` div0) ⋅ 5 }
-decMedian0 e
-    = e { edMedian0 =
-              edMedian0 e - ((edMedian0 e + (div0-2)) `div` div0) ⋅ 2 }
-incMedian1 e
-    = e { edMedian1 =
-              edMedian1 e + ((edMedian1 e +  div1   ) `div` div1) ⋅ 5 }
-decMedian1 e
-    = e { edMedian1 =
-              edMedian1 e - ((edMedian1 e + (div1-2)) `div` div1) ⋅ 2 }
-incMedian2 e
-    = e { edMedian2 =
-              edMedian2 e + ((edMedian2 e +  div2   ) `div` div2) ⋅ 5 }
-decMedian2 e
-    = e { edMedian2 =
-              edMedian2 e - ((edMedian2 e + (div2-2)) `div` div2) ⋅ 2 }
+incMedian0, decMedian0, incMedian1, decMedian1, incMedian2, decMedian2 ∷ EntropyData s → ST s ()
+incMedian0 = flip modifySTRef (\x → x + ((x +  div0   ) `div` div0) ⋅ 5) ∘ edMedian0
+decMedian0 = flip modifySTRef (\x → x - ((x + (div0-2)) `div` div0) ⋅ 2) ∘ edMedian0
+incMedian1 = flip modifySTRef (\x → x + ((x +  div1   ) `div` div1) ⋅ 5) ∘ edMedian1
+decMedian1 = flip modifySTRef (\x → x - ((x + (div1-2)) `div` div1) ⋅ 2) ∘ edMedian1
+incMedian2 = flip modifySTRef (\x → x + ((x +  div2   ) `div` div2) ⋅ 5) ∘ edMedian2
+decMedian2 = flip modifySTRef (\x → x - ((x + (div2-2)) `div` div2) ⋅ 2) ∘ edMedian2