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module Storage(
Store,
createStore,
setPref,
checkPref
) where
import Data.Int ( Int8 )
import Preferences ( Preference )
import qualified Data.Vector.Unboxed.Mutable as Vec
data Store = Store
{ getPointer :: Vec.IOVector Int8
, getBallotSize :: Int }
createStore :: Int -> Int -> IO Store
createStore maxCapacity ballotSize = do
v <- Vec.new (maxCapacity * ballotSize)
return (Store v ballotSize)
setPref :: Store -> Int -> Preference -> IO ()
setPref prefStore ballot (position,rank) = do
let place = (ballot - 1) * (getBallotSize prefStore) + (position - 1)
Vec.write (getPointer prefStore) place (fromIntegral rank)
checkPref :: Store -> Int -> Preference -> IO Bool
checkPref prefStore ballot (position,rank) = do
let place = (ballot - 1) * (getBallotSize prefStore) + (position - 1)
value <- Vec.read (getPointer prefStore) place
return (value == fromIntegral rank)
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