readBlocks

diff --git a/Codec/Audio/WavPack/Block.hs b/Codec/Audio/WavPack/Block.hs
index aff1da3249c0904256f0565e4ad49326816620b9..4ecdb7d8d40e5530f6e8e8846d8ef776320a104a 100644 (file)
--- a/Codec/Audio/WavPack/Block.hs
+++ b/Codec/Audio/WavPack/Block.hs
@@ -9,7 +9,7 @@ module Codec.Audio.WavPack.Block
     , BlockHeader(..)
     , BlockFlags(..)
 
     , BlockHeader(..)
     , BlockFlags(..)
 

-    , findNextBlock
+    , readBlocks

     )
     where
 import Codec.Audio.WavPack.Metadata
     )
     where
 import Codec.Audio.WavPack.Metadata


@@ -286,10 +286,17 @@ decodeSamplingRate 0x0D = S.Just  96000
 decodeSamplingRate 0x0E = S.Just 192000
 decodeSamplingRate    _ =     S.Nothing
 
 decodeSamplingRate 0x0E = S.Just 192000
 decodeSamplingRate    _ =     S.Nothing
 

--- | Find a WavPack block in a given stream. Returns 'S.Nothing' if no
--- blocks are found.
-findNextBlock ∷ L.ByteString -- ^ the input
-              → (# S.Maybe Block, L.ByteString #) -- ^ the rest of input
+-- | Read WavPack blocks in a given stream lazily.
+readBlocks ∷ L.ByteString → [Block]
+readBlocks src
+    = case findNextBlock src of
+        (# S.Just block, src' #)
+            → block : readBlocks src'
+        (# S.Nothing, _ #)
+            → []
+
+findNextBlock ∷ L.ByteString
+              → (# S.Maybe Block, L.ByteString #)

 findNextBlock src
     = case L.uncons src of
         Nothing
 findNextBlock src
     = case L.uncons src of
         Nothing

diff --git a/examples/WvInfo.hs b/examples/WvInfo.hs
index 75c13ab3076510fefdb241e96c152d6fb3be79ab..6631c7b47fcf9ebc6f864b0ef66c33b3d8044c25 100644 (file)
--- a/examples/WvInfo.hs
+++ b/examples/WvInfo.hs
@@ -1,12 +1,10 @@
 {-# LANGUAGE
 {-# LANGUAGE

-    UnboxedTuples
-  , UnicodeSyntax
+    UnicodeSyntax

   #-}
 module Main where
 import Codec.Audio.WavPack.Block
 import Codec.Audio.WavPack.Metadata
 import qualified Data.ByteString.Lazy as L
   #-}
 module Main where
 import Codec.Audio.WavPack.Block
 import Codec.Audio.WavPack.Metadata
 import qualified Data.ByteString.Lazy as L

-import qualified Data.Strict as S

 import Data.Maybe
 import Prelude.Unicode
 import System.Environment
 import Data.Maybe
 import Prelude.Unicode
 import System.Environment


@@ -16,19 +14,13 @@ main ∷ IO ()
 main = do [wvFile] ← getArgs
           wvData   ← L.readFile wvFile
           hSetBuffering stdout NoBuffering
 main = do [wvFile] ← getArgs
           wvData   ← L.readFile wvFile
           hSetBuffering stdout NoBuffering

-          showWvInfo wvData
-
-showWvInfo ∷ L.ByteString → IO ()
-showWvInfo stream
-    = case findNextBlock stream of
-        (# S.Just block, _ #)
-            → printBlock block
-        (# S.Nothing   , _ #)
-            → fail "Can't find any WavPack block headers."
+          mapM_ printBlock $ readBlocks wvData
+          putStrLn "* End of WavPack blocks"

 
 printBlock ∷ Block → IO ()
 printBlock b
 
 printBlock ∷ Block → IO ()
 printBlock b

-    = do putStrLn "- Block header:"
+    = do putStrLn "* WavPack Block"
+         putStrLn "- Block header:"

          print $ blockHeader b
          putStrLn "- Block metadata sub-blocks:"
          mapM_ printSub $ blockMetadata b
          print $ blockHeader b
          putStrLn "- Block metadata sub-blocks:"
          mapM_ printSub $ blockMetadata b


@@ -42,3 +34,18 @@ printBlock b
                          )
           | otherwise
               = print sub
                          )
           | otherwise
               = print sub

+
+{- % du -sh 01.wv
+   15716
+
+   When compiled with -O0:
+   % time ./dist/build/hs-wvinfo/hs-wvinfo 01.wv > /dev/null
+   1.49s user 2.12s system 98% cpu 3.664 total
+
+   When compiled with -O2:
+   % time ./dist/build/hs-wvinfo/hs-wvinfo 01.wv > /dev/null
+   1.35s user 2.09s system 97% cpu 3.520 total
+
+   Hmm... quite disappointing...  The stringification is the
+   bottleneck? If so, I can live with that.
+-}