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Fix bitseq snoc #102

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Fix bitseq snoc #102

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a15b880
Fix BitSeq Snoc instance
blaxill Feb 23, 2023
d67b8ae
Add Monoid instance for BitSeq
blaxill Feb 23, 2023
0596116
Fix BitSeq PopCount1 instance
blaxill Feb 24, 2023
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9 changes: 6 additions & 3 deletions src/HaskellWorks/Data/RankSelect/Internal/BitSeq.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -85,8 +85,8 @@ instance HW.Cons BitSeq where
instance HW.Snoc BitSeq where
snoc (BitSeq ft) b = BitSeq $ case FT.viewr ft of
lt :> Elem w nw -> if nw >= 0 && nw < 64
then Elem (w .|. (bw .<. nw)) (nw + 1) <| lt
else Elem bw 1 <| lt
then lt |> Elem (w .|. (bw .<. nw)) (nw + 1)
else ft |> Elem bw 1
FT.EmptyR -> FT.singleton (Elem bw 1)
where bw = if b then 1 else 0

Expand All @@ -99,6 +99,9 @@ instance Semigroup BitSeq where
FT.EmptyL -> tr
FT.EmptyR -> FT.empty

instance Monoid BitSeq where
mempty = BitSeq mempty

instance Select1 BitSeq where
select1 (BitSeq ft) n = case FT.split (atPopCountBelow n) ft of
(lt, _) -> case FT.viewr lt of
Expand All @@ -112,7 +115,7 @@ instance Rank1 BitSeq where
rank1 bs n = let (lt, _) = splitAt n bs in popCount1 lt

instance PopCount1 BitSeq where
popCount1 (BitSeq ft) = measureBitCount (FT.measure ft :: Measure)
popCount1 (BitSeq ft) = measurePopCount (FT.measure ft :: Measure)

(|>#) :: BitSeqFt -> Elem -> BitSeqFt
(|>#) ft e@(Elem _ wn) = if wn > 0 then ft |> e else ft
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