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streamly/src/Streamly/Internal/Memory/ArrayStream.hs
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1#include "inline.hs"
3-- |
4-- Module : Streamly.Internal.Memory.ArrayStream
5-- Copyright : (c) 2019 Composewell Technologies
6--
7-- License : BSD3
8-- Maintainer : streamly@composewell.com
9-- Stability : experimental
10-- Portability : GHC
11--
12-- Combinators to efficiently manipulate streams of arrays.
13--
14module Streamly.Internal.Memory.ArrayStream
15 (
16 -- * Creation
17 arraysOf
19 -- * Flattening to elements
20 , concat
21 , concatRev
22 , interpose
23 , interposeSuffix
24 , intercalateSuffix
26 -- * Transformation
27 , splitOn
28 , splitOnSuffix
29 , compact -- compact
31 -- * Elimination
32 , toArray
33 )
34where
36import Control.Monad.IO.Class (MonadIO(..))
37-- import Data.Functor.Identity (Identity)
38import Data.Word (Word8)
39import Foreign.ForeignPtr (withForeignPtr)
40import Foreign.Ptr (minusPtr, plusPtr, castPtr)
41import Foreign.Storable (Storable(..))
42import Prelude hiding (length, null, last, map, (!!), read, concat)
44import Streamly.Internal.Memory.Array.Types (Array(..), length)
45import Streamly.Internal.Data.Stream.Serial (SerialT)
46import Streamly.Internal.Data.Stream.StreamK.Type (IsStream)
48import qualified Streamly.Internal.Memory.Array as A
49import qualified Streamly.Internal.Memory.Array.Types as A
50import qualified Streamly.Internal.Prelude as S
51import qualified Streamly.Internal.Data.Stream.StreamD as D
52import qualified Streamly.Internal.Data.Stream.Prelude as P
54-- XXX efficiently compare two streams of arrays. Two streams can have chunks
55-- of different sizes, we can handle that in the stream comparison abstraction.
56-- This could be useful e.g. to fast compare whether two files differ.
58-- | Convert a stream of arrays into a stream of their elements.
59--
60-- Same as the following but more efficient:
61--
62-- > concat = S.concatMap A.read
63--
64-- @since 0.7.0
65{-# INLINE concat #-}
66concat :: (IsStream t, MonadIO m, Storable a) => t m (Array a) -> t m a
67-- concat m = D.fromStreamD $ A.flattenArrays (D.toStreamD m)
68-- concat m = D.fromStreamD $ D.concatMap A.toStreamD (D.toStreamD m)
69concat m = D.fromStreamD $ D.concatMapU A.read (D.toStreamD m)
71-- XXX should we have a reverseArrays API to reverse the stream of arrays
72-- instead?
73--
74-- | Convert a stream of arrays into a stream of their elements reversing the
75-- contents of each array before flattening.
76--
77-- @since 0.7.0
78{-# INLINE concatRev #-}
79concatRev :: (IsStream t, MonadIO m, Storable a) => t m (Array a) -> t m a
80concatRev m = D.fromStreamD $ A.flattenArraysRev (D.toStreamD m)
82-- | Flatten a stream of arrays after inserting the given element between
83-- arrays.
84--
85-- /Internal/
86{-# INLINE interpose #-}
87interpose :: (MonadIO m, IsStream t, Storable a) => a -> t m (Array a) -> t m a
88interpose x = S.interpose x A.read
90{-# INLINE intercalateSuffix #-}
91intercalateSuffix :: (MonadIO m, IsStream t, Storable a)
92 => Array a -> t m (Array a) -> t m a
93intercalateSuffix arr = S.intercalateSuffix arr A.read
95-- | Flatten a stream of arrays appending the given element after each
96-- array.
97--
98-- @since 0.7.0
99{-# INLINE interposeSuffix #-}
100interposeSuffix :: (MonadIO m, IsStream t, Storable a)
101 => a -> t m (Array a) -> t m a
102-- interposeSuffix x = D.fromStreamD . A.unlines x . D.toStreamD
103interposeSuffix x = S.interposeSuffix x A.read
105-- | Split a stream of arrays on a given separator byte, dropping the separator
106-- and coalescing all the arrays between two separators into a single array.
107--
108-- @since 0.7.0
109{-# INLINE splitOn #-}
110splitOn
111 :: (IsStream t, MonadIO m)
112 => Word8
113 -> t m (Array Word8)
114 -> t m (Array Word8)
115splitOn byte s =
116 D.fromStreamD $ D.splitInnerBy (A.breakOn byte) A.spliceTwo $ D.toStreamD s
118{-# INLINE splitOnSuffix #-}
119splitOnSuffix
120 :: (IsStream t, MonadIO m)
121 => Word8
122 -> t m (Array Word8)
123 -> t m (Array Word8)
124-- splitOn byte s = D.fromStreamD $ A.splitOn byte $ D.toStreamD s
125splitOnSuffix byte s =
126 D.fromStreamD $ D.splitInnerBySuffix (A.breakOn byte) A.spliceTwo $ D.toStreamD s
128-- | Coalesce adjacent arrays in incoming stream to form bigger arrays of a
129-- maximum specified size in bytes.
130--
131-- @since 0.7.0
132{-# INLINE compact #-}
133compact :: (MonadIO m, Storable a)
134 => Int -> SerialT m (Array a) -> SerialT m (Array a)
135compact n xs = D.fromStreamD $ A.packArraysChunksOf n (D.toStreamD xs)
137-- | @arraysOf n stream@ groups the elements in the input stream into arrays of
138-- @n@ elements each.
139--
140-- Same as the following but more efficient:
141--
142-- > arraysOf n = S.chunksOf n (A.writeN n)
143--
144-- @since 0.7.0
145{-# INLINE arraysOf #-}
146arraysOf :: (IsStream t, MonadIO m, Storable a)
147 => Int -> t m a -> t m (Array a)
148arraysOf n str =
149 D.fromStreamD $ A.fromStreamDArraysOf n (D.toStreamD str)
151-- XXX Both of these implementations of splicing seem to perform equally well.
152-- We need to perform benchmarks over a range of sizes though.
154-- CAUTION! length must more than equal to lengths of all the arrays in the
155-- stream.
156{-# INLINE spliceArraysLenUnsafe #-}
157spliceArraysLenUnsafe :: (MonadIO m, Storable a)
158 => Int -> SerialT m (Array a) -> m (Array a)
159spliceArraysLenUnsafe len buffered = do
160 arr <- liftIO $ A.newArray len
161 end <- S.foldlM' writeArr (return $ aEnd arr) buffered
162 return $ arr {aEnd = end}
164 where
166 writeArr dst Array{..} =
167 liftIO $ withForeignPtr aStart $ \src -> do
168 let count = aEnd `minusPtr` src
169 A.memcpy (castPtr dst) (castPtr src) count
170 return $ dst `plusPtr` count
172{-# INLINE _spliceArraysBuffered #-}
173_spliceArraysBuffered :: (MonadIO m, Storable a)
174 => SerialT m (Array a) -> m (Array a)
175_spliceArraysBuffered s = do
176 buffered <- P.foldr S.cons S.nil s
177 len <- S.sum (S.map length buffered)
178 spliceArraysLenUnsafe len s
180{-# INLINE spliceArraysRealloced #-}
181spliceArraysRealloced :: forall m a. (MonadIO m, Storable a)
182 => SerialT m (Array a) -> m (Array a)
183spliceArraysRealloced s = do
184 let idst = liftIO $ A.newArray (A.bytesToElemCount (undefined :: a)
185 (A.mkChunkSizeKB 4))
187 arr <- S.foldlM' A.spliceWithDoubling idst s
188 liftIO $ A.shrinkToFit arr
190-- | Given a stream of arrays, splice them all together to generate a single
191-- array. The stream must be /finite/.
192--
193-- @since 0.7.0
194{-# INLINE toArray #-}
195toArray :: (MonadIO m, Storable a) => SerialT m (Array a) -> m (Array a)
196toArray = spliceArraysRealloced
197-- spliceArrays = _spliceArraysBuffered
199-- exponentially increasing sizes of the chunks upto the max limit.
200-- XXX this will be easier to implement with parsers/terminating folds
201-- With this we should be able to reduce the number of chunks/allocations.
202-- The reallocation/copy based toArray can also be implemented using this.
203--
204{-
205{-# INLINE toArraysInRange #-}
206toArraysInRange :: (IsStream t, MonadIO m, Storable a)
207 => Int -> Int -> Fold m (Array a) b -> Fold m a b
208toArraysInRange low high (Fold step initial extract) =
209-}
211{-
212-- | Fold the input to a pure buffered stream (List) of arrays.
213{-# INLINE _toArraysOf #-}
214_toArraysOf :: (MonadIO m, Storable a)
215 => Int -> Fold m a (SerialT Identity (Array a))
216_toArraysOf n = FL.lchunksOf n (A.writeNF n) FL.toStream
217-}