haskell binding

haskell/src/Data/MessagePack/Stream.hs

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+--------------------------------------------------------------------
+-- |
+-- Module    : Data.MessagePack.Stream
+-- Copyright : (c) Hideyuki Tanaka, 2009
+-- License   : BSD3
+--
+-- Maintainer:  tanaka.hideyuki@gmail.com
+-- Stability :  experimental
+-- Portability: portable
+--
+-- Lazy Stream Serializers and Deserializers
+--
+--------------------------------------------------------------------
+
+module Data.MessagePack.Stream(
+  unpackObjects,
+  unpackObjectsFromFile,
+  unpackObjectsFromHandle,
+  unpackObjectsFromString,
+  ) where
+
+import Control.Monad
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS
+import System.IO
+import System.IO.Unsafe
+
+import Data.MessagePack.Base
+import Data.MessagePack.Feed
+
+-- | Unpack objects using given feeder.
+unpackObjects :: Feeder -> IO [Object]
+unpackObjects feeder = do
+  up <- newUnpacker defaultInitialBufferSize
+  f up
+  where
+  f up = unsafeInterleaveIO $ do
+    mbo <- unpackOnce up
+    case mbo of
+      Just o -> do
+        os <- f up
+        return $ o:os
+      Nothing ->
+        return []
+
+  unpackOnce up = do
+    resp <- unpackerExecute up
+    case resp of
+      0 -> do
+        r <- feedOnce up
+        if r
+          then unpackOnce up
+          else return Nothing
+      1 -> do
+        obj <- unpackerData up
+        freeZone =<< unpackerReleaseZone up
+        unpackerReset up
+        return $ Just obj
+      _ ->
+        error $ "unpackerExecute fails: " ++ show resp
+
+  feedOnce up = do
+    dat <- feeder
+    case dat of
+      Nothing ->
+        return False
+      Just bs -> do
+        unpackerFeed up bs
+        return True
+
+-- | Unpack objects from file.
+unpackObjectsFromFile :: FilePath -> IO [Object]
+unpackObjectsFromFile fname =
+  unpackObjects =<< feederFromFile fname
+
+-- | Unpack objects from handle.
+unpackObjectsFromHandle :: Handle -> IO [Object]
+unpackObjectsFromHandle h =
+  unpackObjects =<< feederFromHandle h
+  
+-- | Unpack oobjects from given byte sequence.
+unpackObjectsFromString :: ByteString -> IO [Object]
+unpackObjectsFromString bs =
+  unpackObjects =<< feederFromString bs