e01057f · streamly · git.iko.soy

git.iko.soy/streamly

Move "strip" to Mutable array module

commite01057fa3c9ebab7a67ace44f88ea20dcd63c6e7 authorHarendra Kumar <harendra@composewell.com> dateFri 10 Mar 2023, 20:47 (4 years ago) parent5598e50

2 files changed+39−29

compare with master

unifiedsplit

core/src/Streamly/Internal/Data/Array/Generic.hs+5−29 core/src/Streamly/Internal/Data/Array/Generic/Mut/Type.hs+34

core/src/Streamly/Internal/Data/Array/Generic.hs+5−29

@@ -38,6 +38,7 @@ module Streamly.Internal.Data.Array.Generic

3838

3939 -- * Random Access

4040 , getIndexUnsafe

41+ , getSliceUnsafe

4142 , strip

4243 )

4344where

@@ -217,9 +218,9 @@ writeLastN n = FL.rmapM f (RB.writeLastN n)

217218 arr <- RB.toMutArray 0 n rb

218219 return $ unsafeFreeze arr

219220

220−{-# INLINE sliceUnsafe #-}

221−sliceUnsafe :: Int -> Int -> Array a -> Array a

222−sliceUnsafe offset len (Array cont off1 _) = Array cont (off1 + offset) len

221+{-# INLINE getSliceUnsafe #-}

222+getSliceUnsafe :: Int -> Int -> Array a -> Array a

223+getSliceUnsafe offset len (Array cont off1 _) = Array cont (off1 + offset) len

223224

224225-- XXX This is not efficient as it copies the array. We should support array

225226-- slicing so that we can just refer to the underlying array memory instead of

@@ -229,32 +230,7 @@ sliceUnsafe offset len (Array cont off1 _) = Array cont (off1 + offset) len

229230-- holds true. Returns a slice of the original array.

230231{-# INLINE strip #-}

231232strip :: (a -> Bool) -> Array a -> Array a

232−strip p arr =

233− let lastIndex = length arr - 1

234− indexR = getIndexR lastIndex -- last predicate failing index

235− in if indexR < 0

236− then nil

237− else

238− let indexL = getIndexL 0 -- first predicate failing index

239− in if indexL == 0 && indexR == lastIndex

240− then arr

241− else

242− let newLen = indexR - indexL + 1

243− in sliceUnsafe indexL newLen arr

244−

245− where

246−

247− getIndexR idx

248− | idx < 0 = idx

249− | otherwise =

250− if p (getIndexUnsafe idx arr)

251− then getIndexR (idx - 1)

252− else idx

253−

254− getIndexL idx =

255− if p (getIndexUnsafe idx arr)

256− then getIndexL (idx + 1)

257− else idx

233+strip p arr = unsafeFreeze $ unsafePerformIO $ MArray.strip p (unsafeThaw arr)

258234

259235-------------------------------------------------------------------------------

260236-- Instances

core/src/Streamly/Internal/Data/Array/Generic/Mut/Type.hs+34

@@ -108,6 +108,7 @@ module Streamly.Internal.Data.Array.Generic.Mut.Type

108108 , length

109109

110110 -- * In-place Mutation Algorithms

111+ , strip

111112 -- , reverse

112113 -- , permute

113114 -- , partitionBy

@@ -250,6 +251,8 @@ new n@(I# n#) =

250251 let ma = MutArray arr# 0 0 n

251252 in (# s1#, ma #)

252253

254+-- XXX This could be pure?

255+

253256-- |

254257-- Definition:

255258--

@@ -766,3 +769,34 @@ eq a1 a2 =

766769 if v1 == v2

767770 then loop (i - 1)

768771 else return False

772+

773+{-# INLINE strip #-}

774+strip :: MonadIO m => (a -> Bool) -> MutArray a -> m (MutArray a)

775+strip p arr = liftIO $ do

776+ let lastIndex = length arr - 1

777+ indexR <- getIndexR lastIndex -- last predicate failing index

778+ if indexR < 0

779+ then nil

780+ else do

781+ indexL <- getIndexL 0 -- first predicate failing index

782+ if indexL == 0 && indexR == lastIndex

783+ then return arr

784+ else

785+ let newLen = indexR - indexL + 1

786+ in return $ getSliceUnsafe indexL newLen arr

787+

788+ where

789+

790+ getIndexR idx

791+ | idx < 0 = return idx

792+ | otherwise = do

793+ r <- getIndexUnsafe idx arr

794+ if p r

795+ then getIndexR (idx - 1)

796+ else return idx

797+

798+ getIndexL idx = do

799+ r <- getIndexUnsafe idx arr

800+ if p r

801+ then getIndexL (idx + 1)

802+ else return idx