gameServer/Store.hs
author unc0rr
Sun, 02 Dec 2012 01:25:11 +0400
changeset 8178 8bd087478b48
parent 7751 8c7f5c43ea5e
child 10460 8dcea9087d75
permissions -rw-r--r--
Fix QSettings problems: - Reopen file in ReadOnly mode if it was open in ReadWrite mode and is being read. This is needed for stupid QSettings which opens file in ReadWrite mode just to call readAll() on it. - Implement setSize(0)

{-# LANGUAGE BangPatterns, GeneralizedNewtypeDeriving #-}
module Store(
    ElemIndex(),
    MStore(),
    IStore(),
    newStore,
    addElem,
    removeElem,
    readElem,
    writeElem,
    modifyElem,
    elemExists,
    firstIndex,
    indicesM,
    withIStore,
    withIStore2,
    (!),
    indices
    ) where

import qualified Data.IntSet as IntSet
import qualified Data.Vector as V
import qualified Data.Vector.Mutable as MV
import Data.IORef
import Control.Monad
import Control.DeepSeq


newtype ElemIndex = ElemIndex Int
    deriving (Eq, Show, Read, Ord, NFData)
newtype MStore e = MStore (IORef (IntSet.IntSet, IntSet.IntSet, MV.IOVector e))
newtype IStore e = IStore (IntSet.IntSet, V.Vector e)


firstIndex :: ElemIndex
firstIndex = ElemIndex 0

-- MStore code
initialSize :: Int
initialSize = 16


growFunc :: Int -> Int
growFunc a = a * 3 `div` 2

truncFunc :: Int -> Int
truncFunc a | a > growFunc initialSize = (a `div` 2)
            | otherwise = a


newStore :: IO (MStore e)
newStore = do
    newar <- MV.new initialSize
    new <- newIORef (IntSet.empty, IntSet.fromAscList [0..initialSize - 1], newar)
    return (MStore new)


growStore :: MStore e -> IO ()
growStore (MStore ref) = do
    (busyElems, freeElems, arr) <- readIORef ref
    let oldSize = MV.length arr
    let newSize = growFunc oldSize
    newArr <- MV.grow arr (newSize - oldSize)
    writeIORef ref (busyElems, freeElems `IntSet.union` IntSet.fromAscList [oldSize .. newSize-1], newArr)


growIfNeeded :: MStore e -> IO ()
growIfNeeded m@(MStore ref) = do
    (_, freeElems, _) <- readIORef ref
    when (IntSet.null freeElems) $ growStore m


truncateIfNeeded :: MStore e -> IO ()
truncateIfNeeded (MStore ref) = do
    (busyElems, _, arr) <- readIORef ref
    let oldSize = MV.length arr
    let newSize = truncFunc oldSize
    when (newSize < oldSize && (not $ IntSet.null busyElems) && IntSet.findMax busyElems < newSize) $ do
        writeIORef ref (busyElems, IntSet.fromAscList [0..newSize - 1] `IntSet.difference` busyElems, MV.take newSize arr)


addElem :: MStore e -> e -> IO ElemIndex
addElem m@(MStore ref) element = do
    growIfNeeded m
    (busyElems, freeElems, arr) <- readIORef ref
    let (!n, freeElems') = IntSet.deleteFindMin freeElems
    MV.write arr n element
    writeIORef ref (IntSet.insert n busyElems, freeElems', arr)
    return $ ElemIndex n


removeElem :: MStore e -> ElemIndex -> IO ()
removeElem m@(MStore ref) (ElemIndex n) = do
    (busyElems, freeElems, arr) <- readIORef ref
    MV.write arr n (error $ "Store: no element " ++ show n)
    writeIORef ref (IntSet.delete n busyElems, IntSet.insert n freeElems, arr)
    truncateIfNeeded m


readElem :: MStore e -> ElemIndex -> IO e
readElem (MStore ref) (ElemIndex n) = readIORef ref >>= \(_, _, arr) -> MV.read arr n


writeElem :: MStore e -> ElemIndex -> e -> IO ()
writeElem (MStore ref) (ElemIndex n) el = readIORef ref >>= \(_, _, arr) -> MV.write arr n el


modifyElem :: MStore e -> (e -> e) -> ElemIndex -> IO ()
modifyElem (MStore ref) f (ElemIndex n) = do
    (_, _, arr) <- readIORef ref
    MV.read arr n >>= MV.write arr n . f

elemExists :: MStore e -> ElemIndex -> IO Bool
elemExists (MStore ref) (ElemIndex n) = do
    (_, !free, _) <- readIORef ref
    return $ n `IntSet.notMember` free

indicesM :: MStore e -> IO [ElemIndex]
indicesM (MStore ref) = do
    (!busy, _, _) <- readIORef ref
    return $ map ElemIndex $ IntSet.toList busy


-- A way to see MStore elements in pure code via IStore
m2i :: MStore e -> IO (IStore e)
m2i (MStore ref) = do
    (a, _, c') <- readIORef ref
    c <- V.unsafeFreeze c'
    return $ IStore (a, c)

i2m :: MStore e -> IStore e -> IO ()
i2m (MStore ref) (IStore (_, arr)) = do
    (b, e, _) <- readIORef ref
    a <- V.unsafeThaw arr
    writeIORef ref (b, e, a)

withIStore :: MStore e -> (IStore e -> a) -> IO a
withIStore m f = do
    i <- m2i m
    let res = f i
    res `seq` i2m m i
    return res


withIStore2 :: MStore e1 -> MStore e2 -> (IStore e1 -> IStore e2 -> a) -> IO a
withIStore2 m1 m2 f = do
    i1 <- m2i m1
    i2 <- m2i m2
    let res = f i1 i2
    res `seq` i2m m1 i1
    i2m m2 i2
    return res


-- IStore code
(!) :: IStore e -> ElemIndex -> e
(!) (IStore (_, arr)) (ElemIndex i) = (V.!) arr i

indices :: IStore e -> [ElemIndex]
indices (IStore (busy, _)) = map ElemIndex $ IntSet.toList busy