A space-efficient representation of a succession of Word8 vectors, supporting many efficient operations.

An effectful ByteString contains 8-bit bytes, or by using the operations from Data.ByteString.Streaming.Char8 it can be interpreted as containing 8-bit characters.

Smart constructor for Chunk.

The memory management overhead. Currently this is tuned for GHC only.

The chunk size used for I/O. Currently set to 32k, less the memory management overhead

Construct a succession of chunks from its Church encoding (compare GHC.Exts.build)

Resolve a succession of chunks into its Church encoding; this is not a safe operation; it is equivalent to exposing the constructors

Consume the chunks of an effectful ByteString with a natural right fold.

Consume the chunks of an effectful ByteString with a natural right monadic fold.

The recommended chunk size. Currently set to 4k, less the memory management overhead

Packing and unpacking from lists packBytes' :: Monad m => [Word8] -> ByteString m () packBytes' cs0 = packChunks 32 cs0 where packChunks n cs = case S.packUptoLenBytes n cs of (bs, []) -> Chunk bs (Empty ()) (bs, cs') -> Chunk bs (packChunks (min (n * 2) BI.smallChunkSize) cs') -- packUptoLenBytes :: Int -> [Word8] -> (ByteString, [Word8]) packUptoLenBytes len xs0 = unsafeDupablePerformIO (createUptoN' len $ p -> go p len xs0) where go !_ !n [] = return (len-n, []) go !_ !0 xs = return (len, xs) go !p !n (x:xs) = poke p x >> go (p plusPtr 1) (n-1) xs createUptoN' :: Int -> (Ptr Word8 -> IO (Int, a)) -> IO (S.ByteString, a) createUptoN' l f = do fp <- S.mallocByteString l (l', res) withForeignPtr fp $ p - f p assert (l' <= l) $ return (S.PS fp 0 l', res) {--}

Yield-style smart constructor for Chunk.

Reconceive an effect that results in an effectful bytestring as an effectful bytestring. Compare Streaming.mwrap. The closes equivalent of

>>> Streaming.wrap :: f (Stream f m r) -> Stream f m r

is here consChunk. mwrap is the smart constructor for the internal Go constructor.

Make the information in a bytestring available to more than one eliminating fold, e.g.

>>> Q.count 'l' $ Q.count 'o' $ Q.copy $ "hello\nworld"
3 :> (2 :> ())

>>> Q.length $ Q.count 'l' $ Q.count 'o' $ Q.copy $ Q.copy "hello\nworld"
11 :> (3 :> (2 :> ()))

>>> runResourceT $ Q.writeFile "hello2.txt" $ Q.writeFile "hello1.txt" $ Q.copy $ "hello\nworld\n"
>>> :! cat hello2.txt
hello
world
>>> :! cat hello1.txt
hello
world

This sort of manipulation could as well be acheived by combining folds - using Control.Foldl for example. But any sort of manipulation can be involved in the fold. Here are a couple of trivial complications involving splitting by lines:

>>> let doubleLines = Q.unlines . maps (<* Q.chunk "\n" ) . Q.lines
>>> let emphasize = Q.unlines . maps (<* Q.chunk "!" ) . Q.lines
>>> runResourceT $ Q.writeFile "hello2.txt" $ emphasize $ Q.writeFile "hello1.txt" $ doubleLines $ Q.copy $ "hello\nworld"
>>> :! cat hello2.txt
hello!
world!
>>> :! cat hello1.txt
hello

world

As with the parallel operations in Streaming.Prelude, we have

Q.effects . Q.copy       = id
hoist Q.effects . Q.copy = id

The duplication does not by itself involve the copying of bytestring chunks; it just makes two references to each chunk as it arises. This does, however double the number of constructors associated with each chunk.