{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, BangPatterns #-} -- | -- Module : Data.Vector.Mutable -- Copyright : (c) Roman Leshchinskiy 2008-2010 -- License : BSD-style -- -- Maintainer : Roman Leshchinskiy <rl@cse.unsw.edu.au> -- Stability : experimental -- Portability : non-portable -- -- Mutable boxed vectors. -- module Data.Vector.Mutable ( -- * Mutable boxed vectors MVector(..), IOVector, STVector, -- * Accessors -- ** Length information length, null, -- ** Extracting subvectors slice, init, tail, take, drop, splitAt, unsafeSlice, unsafeInit, unsafeTail, unsafeTake, unsafeDrop, -- ** Overlapping overlaps, -- * Construction -- ** Initialisation new, unsafeNew, replicate, replicateM, clone, -- ** Growing grow, unsafeGrow, -- ** Restricting memory usage clear, -- * Accessing individual elements read, write, swap, unsafeRead, unsafeWrite, unsafeSwap, -- * Modifying vectors -- ** Filling and copying set, copy, move, unsafeCopy, unsafeMove ) where import Control.Monad (when) import qualified Data.Vector.Generic.Mutable as G import Data.Primitive.Array import Control.Monad.Primitive import Prelude hiding ( length, null, replicate, reverse, map, read, take, drop, splitAt, init, tail ) import Data.Typeable ( Typeable ) #include "vector.h" -- | Mutable boxed vectors keyed on the monad they live in ('IO' or @'ST' s@). data MVector s a = MVector {-# UNPACK #-} !Int {-# UNPACK #-} !Int {-# UNPACK #-} !(MutableArray s a) deriving ( Typeable ) type IOVector = MVector RealWorld type STVector s = MVector s instance G.MVector MVector a where {-# INLINE basicLength #-} basicLength (MVector _ n _) = n {-# INLINE basicUnsafeSlice #-} basicUnsafeSlice j m (MVector i n arr) = MVector (i+j) m arr {-# INLINE basicOverlaps #-} basicOverlaps (MVector i m arr1) (MVector j n arr2) = sameMutableArray arr1 arr2 && (between i j (j+n) || between j i (i+m)) where between x y z = x >= y && x < z {-# INLINE basicUnsafeNew #-} basicUnsafeNew n = do arr <- newArray n uninitialised return (MVector 0 n arr) {-# INLINE basicUnsafeReplicate #-} basicUnsafeReplicate n x = do arr <- newArray n x return (MVector 0 n arr) {-# INLINE basicUnsafeRead #-} basicUnsafeRead (MVector i n arr) j = readArray arr (i+j) {-# INLINE basicUnsafeWrite #-} basicUnsafeWrite (MVector i n arr) j x = writeArray arr (i+j) x {-# INLINE basicUnsafeCopy #-} basicUnsafeCopy (MVector i n dst) (MVector j _ src) = copyMutableArray dst i src j n basicUnsafeMove dst@(MVector iDst n arrDst) src@(MVector iSrc _ arrSrc) = case n of 0 -> return () 1 -> readArray arrSrc iSrc >>= writeArray arrDst iDst 2 -> do x <- readArray arrSrc iSrc y <- readArray arrSrc (iSrc + 1) writeArray arrDst iDst x writeArray arrDst (iDst + 1) y _ | overlaps dst src -> case compare iDst iSrc of LT -> moveBackwards arrDst iDst iSrc n EQ -> return () GT | (iDst - iSrc) * 2 < n -> moveForwardsLargeOverlap arrDst iDst iSrc n | otherwise -> moveForwardsSmallOverlap arrDst iDst iSrc n | otherwise -> G.basicUnsafeCopy dst src {-# INLINE basicClear #-} basicClear v = G.set v uninitialised {-# INLINE moveBackwards #-} moveBackwards :: PrimMonad m => MutableArray (PrimState m) a -> Int -> Int -> Int -> m () moveBackwards !arr !dstOff !srcOff !len = INTERNAL_CHECK(check) "moveBackwards" "not a backwards move" (dstOff < srcOff) $ loopM len $ \ i -> readArray arr (srcOff + i) >>= writeArray arr (dstOff + i) {-# INLINE moveForwardsSmallOverlap #-} -- Performs a move when dstOff > srcOff, optimized for when the overlap of the intervals is small. moveForwardsSmallOverlap :: PrimMonad m => MutableArray (PrimState m) a -> Int -> Int -> Int -> m () moveForwardsSmallOverlap !arr !dstOff !srcOff !len = INTERNAL_CHECK(check) "moveForwardsSmallOverlap" "not a forward move" (dstOff > srcOff) $ do tmp <- newArray overlap uninitialised loopM overlap $ \ i -> readArray arr (dstOff + i) >>= writeArray tmp i loopM nonOverlap $ \ i -> readArray arr (srcOff + i) >>= writeArray arr (dstOff + i) loopM overlap $ \ i -> readArray tmp i >>= writeArray arr (dstOff + nonOverlap + i) where nonOverlap = dstOff - srcOff; overlap = len - nonOverlap -- Performs a move when dstOff > srcOff, optimized for when the overlap of the intervals is large. moveForwardsLargeOverlap :: PrimMonad m => MutableArray (PrimState m) a -> Int -> Int -> Int -> m () moveForwardsLargeOverlap !arr !dstOff !srcOff !len = INTERNAL_CHECK(check) "moveForwardsLargeOverlap" "not a forward move" (dstOff > srcOff) $ do queue <- newArray nonOverlap uninitialised loopM nonOverlap $ \ i -> readArray arr (srcOff + i) >>= writeArray queue i let mov !i !qTop = when (i < dstOff + len) $ do x <- readArray arr i y <- readArray queue qTop writeArray arr i y writeArray queue qTop x mov (i+1) (if qTop + 1 >= nonOverlap then 0 else qTop + 1) mov dstOff 0 where nonOverlap = dstOff - srcOff {-# INLINE loopM #-} loopM :: Monad m => Int -> (Int -> m a) -> m () loopM !n k = let go i = when (i < n) (k i >> go (i+1)) in go 0 uninitialised :: a uninitialised = error "Data.Vector.Mutable: uninitialised element" -- Length information -- ------------------ -- | Length of the mutable vector. length :: MVector s a -> Int {-# INLINE length #-} length = G.length -- | Check whether the vector is empty null :: MVector s a -> Bool {-# INLINE null #-} null = G.null -- Extracting subvectors -- --------------------- -- | Yield a part of the mutable vector without copying it. slice :: Int -> Int -> MVector s a -> MVector s a {-# INLINE slice #-} slice = G.slice take :: Int -> MVector s a -> MVector s a {-# INLINE take #-} take = G.take drop :: Int -> MVector s a -> MVector s a {-# INLINE drop #-} drop = G.drop {-# INLINE splitAt #-} splitAt :: Int -> MVector s a -> (MVector s a, MVector s a) splitAt = G.splitAt init :: MVector s a -> MVector s a {-# INLINE init #-} init = G.init tail :: MVector s a -> MVector s a {-# INLINE tail #-} tail = G.tail -- | Yield a part of the mutable vector without copying it. No bounds checks -- are performed. unsafeSlice :: Int -- ^ starting index -> Int -- ^ length of the slice -> MVector s a -> MVector s a {-# INLINE unsafeSlice #-} unsafeSlice = G.unsafeSlice unsafeTake :: Int -> MVector s a -> MVector s a {-# INLINE unsafeTake #-} unsafeTake = G.unsafeTake unsafeDrop :: Int -> MVector s a -> MVector s a {-# INLINE unsafeDrop #-} unsafeDrop = G.unsafeDrop unsafeInit :: MVector s a -> MVector s a {-# INLINE unsafeInit #-} unsafeInit = G.unsafeInit unsafeTail :: MVector s a -> MVector s a {-# INLINE unsafeTail #-} unsafeTail = G.unsafeTail -- Overlapping -- ----------- -- Check whether two vectors overlap. overlaps :: MVector s a -> MVector s a -> Bool {-# INLINE overlaps #-} overlaps = G.overlaps -- Initialisation -- -------------- -- | Create a mutable vector of the given length. new :: PrimMonad m => Int -> m (MVector (PrimState m) a) {-# INLINE new #-} new = G.new -- | Create a mutable vector of the given length. The length is not checked. unsafeNew :: PrimMonad m => Int -> m (MVector (PrimState m) a) {-# INLINE unsafeNew #-} unsafeNew = G.unsafeNew -- | Create a mutable vector of the given length (0 if the length is negative) -- and fill it with an initial value. replicate :: PrimMonad m => Int -> a -> m (MVector (PrimState m) a) {-# INLINE replicate #-} replicate = G.replicate -- | Create a mutable vector of the given length (0 if the length is negative) -- and fill it with values produced by repeatedly executing the monadic action. replicateM :: PrimMonad m => Int -> m a -> m (MVector (PrimState m) a) {-# INLINE replicateM #-} replicateM = G.replicateM -- | Create a copy of a mutable vector. clone :: PrimMonad m => MVector (PrimState m) a -> m (MVector (PrimState m) a) {-# INLINE clone #-} clone = G.clone -- Growing -- ------- -- | Grow a vector by the given number of elements. The number must be -- positive. grow :: PrimMonad m => MVector (PrimState m) a -> Int -> m (MVector (PrimState m) a) {-# INLINE grow #-} grow = G.grow -- | Grow a vector by the given number of elements. The number must be -- positive but this is not checked. unsafeGrow :: PrimMonad m => MVector (PrimState m) a -> Int -> m (MVector (PrimState m) a) {-# INLINE unsafeGrow #-} unsafeGrow = G.unsafeGrow -- Restricting memory usage -- ------------------------ -- | Reset all elements of the vector to some undefined value, clearing all -- references to external objects. This is usually a noop for unboxed vectors. clear :: PrimMonad m => MVector (PrimState m) a -> m () {-# INLINE clear #-} clear = G.clear -- Accessing individual elements -- ----------------------------- -- | Yield the element at the given position. read :: PrimMonad m => MVector (PrimState m) a -> Int -> m a {-# INLINE read #-} read = G.read -- | Replace the element at the given position. write :: PrimMonad m => MVector (PrimState m) a -> Int -> a -> m () {-# INLINE write #-} write = G.write -- | Swap the elements at the given positions. swap :: PrimMonad m => MVector (PrimState m) a -> Int -> Int -> m () {-# INLINE swap #-} swap = G.swap -- | Yield the element at the given position. No bounds checks are performed. unsafeRead :: PrimMonad m => MVector (PrimState m) a -> Int -> m a {-# INLINE unsafeRead #-} unsafeRead = G.unsafeRead -- | Replace the element at the given position. No bounds checks are performed. unsafeWrite :: PrimMonad m => MVector (PrimState m) a -> Int -> a -> m () {-# INLINE unsafeWrite #-} unsafeWrite = G.unsafeWrite -- | Swap the elements at the given positions. No bounds checks are performed. unsafeSwap :: PrimMonad m => MVector (PrimState m) a -> Int -> Int -> m () {-# INLINE unsafeSwap #-} unsafeSwap = G.unsafeSwap -- Filling and copying -- ------------------- -- | Set all elements of the vector to the given value. set :: PrimMonad m => MVector (PrimState m) a -> a -> m () {-# INLINE set #-} set = G.set -- | Copy a vector. The two vectors must have the same length and may not -- overlap. copy :: PrimMonad m => MVector (PrimState m) a -> MVector (PrimState m) a -> m () {-# INLINE copy #-} copy = G.copy -- | Copy a vector. The two vectors must have the same length and may not -- overlap. This is not checked. unsafeCopy :: PrimMonad m => MVector (PrimState m) a -- ^ target -> MVector (PrimState m) a -- ^ source -> m () {-# INLINE unsafeCopy #-} unsafeCopy = G.unsafeCopy -- | Move the contents of a vector. The two vectors must have the same -- length. -- -- If the vectors do not overlap, then this is equivalent to 'copy'. -- Otherwise, the copying is performed as if the source vector were -- copied to a temporary vector and then the temporary vector was copied -- to the target vector. move :: PrimMonad m => MVector (PrimState m) a -> MVector (PrimState m) a -> m () {-# INLINE move #-} move = G.move -- | Move the contents of a vector. The two vectors must have the same -- length, but this is not checked. -- -- If the vectors do not overlap, then this is equivalent to 'unsafeCopy'. -- Otherwise, the copying is performed as if the source vector were -- copied to a temporary vector and then the temporary vector was copied -- to the target vector. unsafeMove :: PrimMonad m => MVector (PrimState m) a -- ^ target -> MVector (PrimState m) a -- ^ source -> m () {-# INLINE unsafeMove #-} unsafeMove = G.unsafeMove