{-# LANGUAGE FlexibleInstances #-}

module HaskellWorks.Data.Bits.PopCount.PopCount1
    ( PopCount1(..)
    ) where

import Data.Word
import HaskellWorks.Data.Bits.BitWise
import HaskellWorks.Data.Bits.Types.Broadword
import HaskellWorks.Data.Bits.Types.Builtin
import HaskellWorks.Data.Int.Widen.Widen64
import HaskellWorks.Data.Positioning
import Prelude                                as P

import qualified Data.Bits            as DB
import qualified Data.Vector          as DV
import qualified Data.Vector.Storable as DVS

type FastWord a = Builtin a

fastWord :: a -> FastWord a
fastWord = Builtin
{-# INLINE fastWord #-}

class PopCount1 v where
  -- | The number of 0-bits in the value.
  popCount1 :: v -> Count

instance PopCount1 Bool where
  popCount1 True  = 1
  popCount1 False = 0
  {-# INLINE popCount1 #-}

instance PopCount1 (Broadword Word8) where
  popCount1 (Broadword x0) = widen64 x3
    where
      x1 = x0 - ((x0 .&. 0xaa) .>. 1)
      x2 = (x1 .&. 0x33) + ((x1 .>. 2) .&. 0x33)
      x3 = (x2 + (x2 .>. 4)) .&. 0x0f
  {-# INLINE popCount1 #-}

instance PopCount1 (Broadword Word16) where
  popCount1 (Broadword x0) = widen64 ((x3 * 0x0101) .>. 8)
    where
      x1 = x0 - ((x0 .&. 0xaaaa) .>. 1)
      x2 = (x1 .&. 0x3333) + ((x1 .>. 2) .&. 0x3333)
      x3 = (x2 + (x2 .>. 4)) .&. 0x0f0f
  {-# INLINE popCount1 #-}

instance PopCount1 (Broadword Word32) where
  popCount1 (Broadword x0) = widen64 ((x3 * 0x01010101) .>. 24)
    where
      x1 = x0 - ((x0 .&. 0xaaaaaaaa) .>. 1)
      x2 = (x1 .&. 0x33333333) + ((x1 .>. 2) .&. 0x33333333)
      x3 = (x2 + (x2 .>. 4)) .&. 0x0f0f0f0f
  {-# INLINE popCount1 #-}

instance PopCount1 (Broadword Word64) where
  popCount1 (Broadword x0) = widen64 (x3 * 0x0101010101010101) .>. 56
    where
      x1 = x0 - ((x0 .&. 0xaaaaaaaaaaaaaaaa) .>. 1)
      x2 = (x1 .&. 0x3333333333333333) + ((x1 .>. 2) .&. 0x3333333333333333)
      x3 = (x2 + (x2 .>. 4)) .&. 0x0f0f0f0f0f0f0f0f
  {-# INLINE popCount1 #-}

instance PopCount1 (Builtin Word8) where
  popCount1 (Builtin x0) = fromIntegral (DB.popCount x0)
  {-# INLINE popCount1 #-}

instance PopCount1 (Builtin Word16) where
  popCount1 (Builtin x0) = fromIntegral (DB.popCount x0)
  {-# INLINE popCount1 #-}

instance PopCount1 (Builtin Word32) where
  popCount1 (Builtin x0) = fromIntegral (DB.popCount x0)
  {-# INLINE popCount1 #-}

instance PopCount1 (Builtin Word64) where
  popCount1 (Builtin x0) = fromIntegral (DB.popCount x0)
  {-# INLINE popCount1 #-}

instance PopCount1 Word8 where
  popCount1 = fromIntegral . popCount1 . fastWord
  {-# INLINE popCount1 #-}

instance PopCount1 Word16 where
  popCount1 = fromIntegral . popCount1 . fastWord
  {-# INLINE popCount1 #-}

instance PopCount1 Word32 where
  popCount1 = fromIntegral . popCount1 . fastWord
  {-# INLINE popCount1 #-}

instance PopCount1 Word64 where
  popCount1 = fromIntegral . popCount1 . fastWord
  {-# INLINE popCount1 #-}

instance PopCount1 a => PopCount1 [a] where
  popCount1 = P.sum . fmap popCount1
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector Word8) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector Word16) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector Word32) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector Word64) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector Word8) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector Word16) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector Word32) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector Word64) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

-- Vector of Builtin instances

instance PopCount1 (DV.Vector (Builtin Word8)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Builtin Word16)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Builtin Word32)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Builtin Word64)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Builtin Word8)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Builtin Word16)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Builtin Word32)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Builtin Word64)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

-- Vector of Broadword instances

instance PopCount1 (DV.Vector (Broadword Word8)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Broadword Word16)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Broadword Word32)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DV.Vector (Broadword Word64)) where
  popCount1 = DV.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Broadword Word8)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Broadword Word16)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Broadword Word32)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}

instance PopCount1 (DVS.Vector (Broadword Word64)) where
  popCount1 = DVS.foldl' (\c -> (c +) . popCount1) 0
  {-# INLINE popCount1 #-}