91991f9 · typerep-map · git.iko.soy

git.iko.soy/typerep-map

Improve delete & insert performance (#94)

* Improve delete performance * Improve insert performance * Add Big O Docs

commit91991f97531071b78a57e4f0fc43f0fd16d6f7bc authorChris Penner <christopher.penner@gmail.com> dateMon 12 Oct 2020, 12:33 (6 years ago) parentaeef5b8

2 files changed+16−11

compare with main

unifiedsplit

src/Data/TMap.hs+4 src/Data/TypeRepMap/Internal.hs+12−11

src/Data/TMap.hs+4

@@ -87,6 +87,7 @@ one x = coerce (F.one @a @Identity $ coerce x)

8787{- |

8888

8989Insert a value into a 'TMap'.

90+TMap optimizes for fast reads rather than inserts, as a trade-off inserts are @O(n)@.

9091

9192prop> size (insert v tm) >= size tm

9293prop> member @a (insert (x :: a) tm) == True

@@ -98,6 +99,9 @@ insert x = coerce (F.insert @a @Identity $ coerce x)

9899

99100{- | Delete a value from a 'TMap'.

100101

102+TMap optimizes for fast reads rather than modifications, as a trade-off deletes are @O(n)@,

103+with an @O(log(n))@ optimization for when the element is already missing.

104+

101105prop> size (delete @a tm) <= size tm

102106prop> member @a (delete @a tm) == False

103107

src/Data/TypeRepMap/Internal.hs+12−11

@@ -180,19 +180,14 @@ one x = TypeRepMap (primArrayFromListN 1 [fa])

180180{- |

181181

182182Insert a value into a 'TypeRepMap'.

183+TypeRepMap optimizes for fast reads rather than inserts, as a trade-off inserts are @O(n)@.

183184

184185prop> size (insert v tm) >= size tm

185186prop> member @a (insert (x :: f a) tm) == True

186187

187188-}

188189insert :: forall a f . Typeable a => f a -> TypeRepMap f -> TypeRepMap f

189−insert x = fromTriples . addX . toTriples

190− where

191− tripleX :: (Fingerprint, Any, Any)

192− tripleX@(fpX, _, _) = (calcFp @a, toAny x, unsafeCoerce $ typeRep @a)

193−

194− addX :: [(Fingerprint, Any, Any)] -> [(Fingerprint, Any, Any)]

195− addX l = tripleX : deleteByFst fpX l

190+insert = union . one

196191{-# INLINE insert #-}

197192

198193-- Extract the kind of a type. We use it to work around lack of syntax for

@@ -201,6 +196,9 @@ type KindOf (a :: k) = k

201196

202197{- | Delete a value from a 'TypeRepMap'.

203198

199+TypeRepMap optimizes for fast reads rather than modifications, as a trade-off deletes are

200+@O(n)@, with an @O(log(n))@ optimization for when the element is already missing.

201+

204202prop> size (delete @a tm) <= size tm

205203prop> member @a (delete @a tm) == False

206204

@@ -213,7 +211,13 @@ False

213211True

214212-}

215213delete :: forall a (f :: KindOf a -> Type) . Typeable a => TypeRepMap f -> TypeRepMap f

216−delete = fromTriples . deleteByFst (typeFp @a) . toTriples

214+delete m

215+ -- Lookups are fast, so check if we even have the element first.

216+ | not (member @a m) = m

217+ -- We know we have the element, If the map has exactly one element, we can return the empty map

218+ | size m == 1 = empty

219+ -- Otherwise, filter out the element in linear time.

220+ | otherwise = fromSortedTriples . filter ((/= typeFp @a) . fst3) . toSortedTriples $ m

217221{-# INLINE delete #-}

218222

219223{- |

@@ -407,9 +411,6 @@ toSortedTriples tm = trip <$> ordering

407411 ordering :: [ Int ]

408412 ordering = generateOrderMapping (size tm)

409413

410−deleteByFst :: Eq a => a -> [(a, b, c)] -> [(a, b, c)]

411−deleteByFst x = filter ((/= x) . fst3)

412−

413414nubByFst :: (Eq a) => [(a, b, c)] -> [(a, b, c)]

414415nubByFst = nubBy ((==) `on` fst3)

415416