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fix(xanthous): Make floodFill faster

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Speed up the floodFill algorithm by sprinkling in some strictness and
specializing it to the only type it's currently called at anyway.

Change-Id: I4557fc51b1c1036c127bfd5bee50748d8692ae74
Reviewed-on: https://cl.tvl.fyi/c/depot/+/555
Reviewed-by: glittershark <grfn@gws.fyi>
This commit is contained in:
Griffin Smith 2020-06-21 20:26:34 -04:00 • committed by glittershark
parent fbbb284444
commit 0367e8c303
1 changed files with 4 additions and 1 deletions
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5
users/glittershark/xanthous/src/Xanthous/Generators/Util.hs
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@ -163,9 +163,11 @@ floodFill = go mempty
(if y == maxBound then y else succ y)] (if y == maxBound then y else succ y)]
in foldl' (\r idx' -> in foldl' (\r idx' ->
if arr ! idx' if arr ! idx'
then r <> go (r & contains idx' .~ True) arr idx' then r <> (let r' = r & contains idx' .~ True
in r' `seq` go r' arr idx')
else r) else r)
(res & contains idx .~ True) neighbors (res & contains idx .~ True) neighbors
{-# SPECIALIZE floodFill :: UArray (Word, Word) Bool -> (Word, Word) -> Set (Word, Word) #-}
-- | Gives a list of all the disconnected regions in a cell array, represented -- | Gives a list of all the disconnected regions in a cell array, represented
-- each as lists of points -- each as lists of points
@ -188,6 +190,7 @@ regions arr
where where
findFirstPoint :: a (i, j) Bool -> Maybe (i, j) findFirstPoint :: a (i, j) Bool -> Maybe (i, j)
findFirstPoint = fmap fst . headMay . filter snd . assocs findFirstPoint = fmap fst . headMay . filter snd . assocs
{-# SPECIALIZE regions :: UArray (Word, Word) Bool -> [Set (Word, Word)] #-}
fillAll :: (IArray a Bool, Ix i, Foldable f) => f i -> a i Bool -> a i Bool fillAll :: (IArray a Bool, Ix i, Foldable f) => f i -> a i Bool -> a i Bool
fillAll ixes a = accum (const fst) a $ (, (False, ())) <$> toList ixes fillAll ixes a = accum (const fst) a $ (, (False, ())) <$> toList ixes