{-# LANGUAGE CPP #-} {-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE RoleAnnotations #-} {-# LANGUAGE ScopedTypeVariables #-} -- | -- Module : Data.Vector.Primitive.Mutable -- Copyright : (c) Roman Leshchinskiy 2008-2010 -- Alexey Kuleshevich 2020-2022 -- Aleksey Khudyakov 2020-2022 -- Andrew Lelechenko 2020-2022 -- License : BSD-style -- -- Maintainer : Haskell Libraries Team -- Stability : experimental -- Portability : non-portable -- -- Mutable primitive vectors. module Data.Vector.Primitive.Mutable ( -- * Mutable vectors of primitive types 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, generate, generateM, clone, -- ** Growing grow, unsafeGrow, -- ** Restricting memory usage clear, -- * Accessing individual elements read, readMaybe, write, modify, modifyM, swap, exchange, unsafeRead, unsafeWrite, unsafeModify, unsafeModifyM, unsafeSwap, unsafeExchange, -- * Folds mapM_, imapM_, forM_, iforM_, foldl, foldl', foldM, foldM', foldr, foldr', foldrM, foldrM', ifoldl, ifoldl', ifoldM, ifoldM', ifoldr, ifoldr', ifoldrM, ifoldrM', -- * Modifying vectors nextPermutation, -- ** Filling and copying set, copy, move, unsafeCopy, unsafeMove, -- * Unsafe conversions unsafeCoerceMVector, unsafeCast, -- * Re-exports Prim, PrimMonad, PrimState, RealWorld ) where import qualified Data.Vector.Generic.Mutable as G import Data.Primitive.ByteArray import Data.Primitive ( Prim, sizeOf ) import Data.Vector.Internal.Check import Data.Word ( Word8 ) import Control.Monad.Primitive import Control.Monad ( liftM ) import Control.DeepSeq ( NFData(rnf) #if MIN_VERSION_deepseq(1,4,3) , NFData1(liftRnf) #endif ) import Prelude hiding ( length, null, replicate, reverse, map, read, take, drop, splitAt, init, tail, foldr, foldl, mapM_ ) import Data.Typeable ( Typeable ) import Data.Coerce import Unsafe.Coerce -- Data.Vector.Internal.Check is unnecessary #define NOT_VECTOR_MODULE #include "vector.h" type role MVector nominal nominal -- | /O(1)/ Unsafely coerce a mutable vector from one element type to another, -- representationally equal type. The operation just changes the type of the -- underlying pointer and does not modify the elements. -- -- Note that this function is unsafe. The @Coercible@ constraint guarantees -- that the element types are representationally equal. It however cannot -- guarantee that their respective 'Prim' instances are compatible. unsafeCoerceMVector :: Coercible a b => MVector s a -> MVector s b unsafeCoerceMVector = unsafeCoerce -- | Mutable vectors of primitive types. data MVector s a = MVector {-# UNPACK #-} !Int -- ^ offset {-# UNPACK #-} !Int -- ^ length {-# UNPACK #-} !(MutableByteArray s) -- ^ underlying mutable byte array deriving ( Typeable ) type IOVector = MVector RealWorld type STVector s = MVector s instance NFData (MVector s a) where rnf (MVector _ _ _) = () #if MIN_VERSION_deepseq(1,4,3) instance NFData1 (MVector s) where liftRnf _ (MVector _ _ _) = () #endif instance Prim a => G.MVector MVector a where basicLength (MVector _ n _) = n basicUnsafeSlice j m (MVector i _ arr) = MVector (i+j) m arr {-# INLINE basicOverlaps #-} basicOverlaps (MVector i m arr1) (MVector j n arr2) = sameMutableByteArray 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 | n < 0 = error $ "Primitive.basicUnsafeNew: negative length: " ++ show n | n > mx = error $ "Primitive.basicUnsafeNew: length too large: " ++ show n | otherwise = MVector 0 n `liftM` newByteArray (n * size) where size = sizeOf (undefined :: a) mx = maxBound `div` size :: Int {-# INLINE basicInitialize #-} basicInitialize (MVector off n v) = setByteArray v (off * size) (n * size) (0 :: Word8) where size = sizeOf (undefined :: a) {-# INLINE basicUnsafeRead #-} basicUnsafeRead (MVector i _ arr) j = readByteArray arr (i+j) {-# INLINE basicUnsafeWrite #-} basicUnsafeWrite (MVector i _ arr) j x = writeByteArray arr (i+j) x {-# INLINE basicUnsafeCopy #-} basicUnsafeCopy (MVector i n dst) (MVector j _ src) = copyMutableByteArray dst (i*sz) src (j*sz) (n*sz) where sz = sizeOf (undefined :: a) {-# INLINE basicUnsafeMove #-} basicUnsafeMove (MVector i n dst) (MVector j _ src) = moveByteArray dst (i*sz) src (j*sz) (n * sz) where sz = sizeOf (undefined :: a) {-# INLINE basicSet #-} basicSet (MVector i n arr) x = setByteArray arr i n x -- Length information -- ------------------ -- | Length of the mutable vector. length :: Prim a => MVector s a -> Int {-# INLINE length #-} length = G.length -- | Check whether the vector is empty. null :: Prim a => MVector s a -> Bool {-# INLINE null #-} null = G.null -- Extracting subvectors -- --------------------- -- | Yield a part of the mutable vector without copying it. The vector must -- contain at least @i+n@ elements. slice :: Prim a => Int -- ^ @i@ starting index -> Int -- ^ @n@ length -> MVector s a -> MVector s a {-# INLINE slice #-} slice = G.slice -- | Take the @n@ first elements of the mutable vector without making a -- copy. For negative @n@, the empty vector is returned. If @n@ is larger -- than the vector's length, the vector is returned unchanged. take :: Prim a => Int -> MVector s a -> MVector s a {-# INLINE take #-} take = G.take -- | Drop the @n@ first element of the mutable vector without making a -- copy. For negative @n@, the vector is returned unchanged. If @n@ is -- larger than the vector's length, the empty vector is returned. drop :: Prim a => Int -> MVector s a -> MVector s a {-# INLINE drop #-} drop = G.drop -- | /O(1)/ Split the mutable vector into the first @n@ elements -- and the remainder, without copying. -- -- Note that @'splitAt' n v@ is equivalent to @('take' n v, 'drop' n v)@, -- but slightly more efficient. splitAt :: Prim a => Int -> MVector s a -> (MVector s a, MVector s a) {-# INLINE splitAt #-} splitAt = G.splitAt -- | Drop the last element of the mutable vector without making a copy. -- If the vector is empty, an exception is thrown. init :: Prim a => MVector s a -> MVector s a {-# INLINE init #-} init = G.init -- | Drop the first element of the mutable vector without making a copy. -- If the vector is empty, an exception is thrown. tail :: Prim a => 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 :: Prim a => Int -- ^ starting index -> Int -- ^ length of the slice -> MVector s a -> MVector s a {-# INLINE unsafeSlice #-} unsafeSlice = G.unsafeSlice -- | Unsafe variant of 'take'. If @n@ is out of range, it will -- simply create an invalid slice that likely violate memory safety. unsafeTake :: Prim a => Int -> MVector s a -> MVector s a {-# INLINE unsafeTake #-} unsafeTake = G.unsafeTake -- | Unsafe variant of 'drop'. If @n@ is out of range, it will -- simply create an invalid slice that likely violate memory safety. unsafeDrop :: Prim a => Int -> MVector s a -> MVector s a {-# INLINE unsafeDrop #-} unsafeDrop = G.unsafeDrop -- | Same as 'init', but doesn't do range checks. unsafeInit :: Prim a => MVector s a -> MVector s a {-# INLINE unsafeInit #-} unsafeInit = G.unsafeInit -- | Same as 'tail', but doesn't do range checks. unsafeTail :: Prim a => MVector s a -> MVector s a {-# INLINE unsafeTail #-} unsafeTail = G.unsafeTail -- Overlapping -- ----------- -- | Check whether two vectors overlap. overlaps :: Prim a => MVector s a -> MVector s a -> Bool {-# INLINE overlaps #-} overlaps = G.overlaps -- Initialisation -- -------------- -- | Create a mutable vector of the given length. new :: (PrimMonad m, Prim a) => Int -> m (MVector (PrimState m) a) {-# INLINE new #-} new = G.new -- | Create a mutable vector of the given length. The vector content -- is uninitialized, which means it is filled with whatever the -- underlying memory buffer happens to contain. -- -- @since 0.5 unsafeNew :: (PrimMonad m, Prim a) => 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, Prim a) => 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, Prim a) => Int -> m a -> m (MVector (PrimState m) a) {-# INLINE replicateM #-} replicateM = G.replicateM -- | /O(n)/ Create a mutable vector of the given length (0 if the length is negative) -- and fill it with the results of applying the function to each index. -- Iteration starts at index 0. -- -- @since 0.12.3.0 generate :: (PrimMonad m, Prim a) => Int -> (Int -> a) -> m (MVector (PrimState m) a) {-# INLINE generate #-} generate = G.generate -- | /O(n)/ Create a mutable vector of the given length (0 if the length is -- negative) and fill it with the results of applying the monadic function to each -- index. Iteration starts at index 0. -- -- @since 0.12.3.0 generateM :: (PrimMonad m, Prim a) => Int -> (Int -> m a) -> m (MVector (PrimState m) a) {-# INLINE generateM #-} generateM = G.generateM -- | Create a copy of a mutable vector. clone :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> m (MVector (PrimState m) a) {-# INLINE clone #-} clone = G.clone -- Growing -- ------- -- | Grow a primitive vector by the given number of elements. The number must be -- non-negative. This has the same semantics as 'G.grow' for generic vectors. -- -- ==== __Examples__ -- -- >>> import qualified Data.Vector.Primitive as VP -- >>> import qualified Data.Vector.Primitive.Mutable as MVP -- >>> mv <- VP.thaw $ VP.fromList ([10, 20, 30] :: [Int]) -- >>> mv' <- MVP.grow mv 2 -- -- Extra memory at the end of the newly allocated vector is initialized to 0 -- bytes, which for 'Prim' instances will usually correspond to some default -- value for a particular type, e.g. @0@ for @Int@, @\NUL@ for @Char@, -- etc. However, if 'unsafeGrow' was used instead, this would not have been -- guaranteed and some garbage would be there instead. -- -- >>> VP.freeze mv' -- [10,20,30,0,0] -- -- Having the extra space we can write new values in there: -- -- >>> MVP.write mv' 3 999 -- >>> VP.freeze mv' -- [10,20,30,999,0] -- -- It is important to note that the source mutable vector is not affected when -- the newly allocated one is mutated. -- -- >>> MVP.write mv' 2 888 -- >>> VP.freeze mv' -- [10,20,888,999,0] -- >>> VP.freeze mv -- [10,20,30] -- -- @since 0.5 grow :: (PrimMonad m, Prim a) => 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 non-negative, but -- this is not checked. This has the same semantics as 'G.unsafeGrow' for generic vectors. -- -- @since 0.5 unsafeGrow :: (PrimMonad m, Prim a) => 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 a noop. clear :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> m () {-# INLINE clear #-} clear = G.clear -- Accessing individual elements -- ----------------------------- -- | Yield the element at the given position. Will throw an exception if -- the index is out of range. -- -- ==== __Examples__ -- -- >>> import qualified Data.Vector.Primitive.Mutable as MVP -- >>> v <- MVP.generate 10 (\x -> x*x) -- >>> MVP.read v 3 -- 9 read :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> m a {-# INLINE read #-} read = G.read -- | Yield the element at the given position. Returns 'Nothing' if -- the index is out of range. -- -- @since 0.13 -- -- ==== __Examples__ -- -- >>> import qualified Data.Vector.Primitive.Mutable as MVP -- >>> v <- MVP.generate 10 (\x -> x*x) -- >>> MVP.readMaybe v 3 -- Just 9 -- >>> MVP.readMaybe v 13 -- Nothing readMaybe :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> m (Maybe a) {-# INLINE readMaybe #-} readMaybe = G.readMaybe -- | Replace the element at the given position. write :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> a -> m () {-# INLINE write #-} write = G.write -- | Modify the element at the given position. modify :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (a -> a) -> Int -> m () {-# INLINE modify #-} modify = G.modify -- | Modify the element at the given position using a monadic function. -- -- @since 0.12.3.0 modifyM :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (a -> m a) -> Int -> m () {-# INLINE modifyM #-} modifyM = G.modifyM -- | Swap the elements at the given positions. swap :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> Int -> m () {-# INLINE swap #-} swap = G.swap -- | Replace the element at the given position and return the old element. exchange :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> a -> m a {-# INLINE exchange #-} exchange = G.exchange -- | Yield the element at the given position. No bounds checks are performed. unsafeRead :: (PrimMonad m, Prim a) => 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, Prim a) => MVector (PrimState m) a -> Int -> a -> m () {-# INLINE unsafeWrite #-} unsafeWrite = G.unsafeWrite -- | Modify the element at the given position. No bounds checks are performed. unsafeModify :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (a -> a) -> Int -> m () {-# INLINE unsafeModify #-} unsafeModify = G.unsafeModify -- | Modify the element at the given position using a monadic -- function. No bounds checks are performed. -- -- @since 0.12.3.0 unsafeModifyM :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (a -> m a) -> Int -> m () {-# INLINE unsafeModifyM #-} unsafeModifyM = G.unsafeModifyM -- | Swap the elements at the given positions. No bounds checks are performed. unsafeSwap :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> Int -> m () {-# INLINE unsafeSwap #-} unsafeSwap = G.unsafeSwap -- | Replace the element at the given position and return the old element. No -- bounds checks are performed. unsafeExchange :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> Int -> a -> m a {-# INLINE unsafeExchange #-} unsafeExchange = G.unsafeExchange -- Filling and copying -- ------------------- -- | Set all elements of the vector to the given value. set :: (PrimMonad m, Prim a) => 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, Prim a) => MVector (PrimState m) a -- ^ target -> MVector (PrimState m) a -- ^ source -> m () {-# INLINE copy #-} copy = G.copy -- | Copy a vector. The two vectors must have the same length and may not -- overlap, but this is not checked. unsafeCopy :: (PrimMonad m, Prim a) => 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, Prim a) => MVector (PrimState m) a -- ^ target -> MVector (PrimState m) a -- ^ source -> 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, Prim a) => MVector (PrimState m) a -- ^ target -> MVector (PrimState m) a -- ^ source -> m () {-# INLINE unsafeMove #-} unsafeMove = G.unsafeMove -- Modifying vectors -- ----------------- -- | Compute the (lexicographically) next permutation of the given vector in-place. -- Returns False when the input is the last permutation. nextPermutation :: (PrimMonad m,Ord e,Prim e) => MVector (PrimState m) e -> m Bool {-# INLINE nextPermutation #-} nextPermutation = G.nextPermutation -- Folds -- ----- -- | /O(n)/ Apply the monadic action to every element of the vector, discarding the results. -- -- @since 0.12.3.0 mapM_ :: (PrimMonad m, Prim a) => (a -> m b) -> MVector (PrimState m) a -> m () {-# INLINE mapM_ #-} mapM_ = G.mapM_ -- | /O(n)/ Apply the monadic action to every element of the vector and its index, discarding the results. -- -- @since 0.12.3.0 imapM_ :: (PrimMonad m, Prim a) => (Int -> a -> m b) -> MVector (PrimState m) a -> m () {-# INLINE imapM_ #-} imapM_ = G.imapM_ -- | /O(n)/ Apply the monadic action to every element of the vector, -- discarding the results. It's the same as @flip mapM_@. -- -- @since 0.12.3.0 forM_ :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (a -> m b) -> m () {-# INLINE forM_ #-} forM_ = G.forM_ -- | /O(n)/ Apply the monadic action to every element of the vector -- and its index, discarding the results. It's the same as @flip imapM_@. -- -- @since 0.12.3.0 iforM_ :: (PrimMonad m, Prim a) => MVector (PrimState m) a -> (Int -> a -> m b) -> m () {-# INLINE iforM_ #-} iforM_ = G.iforM_ -- | /O(n)/ Pure left fold. -- -- @since 0.12.3.0 foldl :: (PrimMonad m, Prim a) => (b -> a -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldl #-} foldl = G.foldl -- | /O(n)/ Pure left fold with strict accumulator. -- -- @since 0.12.3.0 foldl' :: (PrimMonad m, Prim a) => (b -> a -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldl' #-} foldl' = G.foldl' -- | /O(n)/ Pure left fold using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldl :: (PrimMonad m, Prim a) => (b -> Int -> a -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldl #-} ifoldl = G.ifoldl -- | /O(n)/ Pure left fold with strict accumulator using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldl' :: (PrimMonad m, Prim a) => (b -> Int -> a -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldl' #-} ifoldl' = G.ifoldl' -- | /O(n)/ Pure right fold. -- -- @since 0.12.3.0 foldr :: (PrimMonad m, Prim a) => (a -> b -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldr #-} foldr = G.foldr -- | /O(n)/ Pure right fold with strict accumulator. -- -- @since 0.12.3.0 foldr' :: (PrimMonad m, Prim a) => (a -> b -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldr' #-} foldr' = G.foldr' -- | /O(n)/ Pure right fold using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldr :: (PrimMonad m, Prim a) => (Int -> a -> b -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldr #-} ifoldr = G.ifoldr -- | /O(n)/ Pure right fold with strict accumulator using a function applied -- to each element and its index. -- -- @since 0.12.3.0 ifoldr' :: (PrimMonad m, Prim a) => (Int -> a -> b -> b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldr' #-} ifoldr' = G.ifoldr' -- | /O(n)/ Monadic fold. -- -- @since 0.12.3.0 foldM :: (PrimMonad m, Prim a) => (b -> a -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldM #-} foldM = G.foldM -- | /O(n)/ Monadic fold with strict accumulator. -- -- @since 0.12.3.0 foldM' :: (PrimMonad m, Prim a) => (b -> a -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldM' #-} foldM' = G.foldM' -- | /O(n)/ Monadic fold using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldM :: (PrimMonad m, Prim a) => (b -> Int -> a -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldM #-} ifoldM = G.ifoldM -- | /O(n)/ Monadic fold with strict accumulator using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldM' :: (PrimMonad m, Prim a) => (b -> Int -> a -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldM' #-} ifoldM' = G.ifoldM' -- | /O(n)/ Monadic right fold. -- -- @since 0.12.3.0 foldrM :: (PrimMonad m, Prim a) => (a -> b -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldrM #-} foldrM = G.foldrM -- | /O(n)/ Monadic right fold with strict accumulator. -- -- @since 0.12.3.0 foldrM' :: (PrimMonad m, Prim a) => (a -> b -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE foldrM' #-} foldrM' = G.foldrM' -- | /O(n)/ Monadic right fold using a function applied to each element and its index. -- -- @since 0.12.3.0 ifoldrM :: (PrimMonad m, Prim a) => (Int -> a -> b -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldrM #-} ifoldrM = G.ifoldrM -- | /O(n)/ Monadic right fold with strict accumulator using a function applied -- to each element and its index. -- -- @since 0.12.3.0 ifoldrM' :: (PrimMonad m, Prim a) => (Int -> a -> b -> m b) -> b -> MVector (PrimState m) a -> m b {-# INLINE ifoldrM' #-} ifoldrM' = G.ifoldrM' -- Unsafe conversions -- ------------------ -- | /O(1)/ Unsafely cast a vector from one element type to another. -- This operation just changes the type of the vector and does not -- modify the elements. -- -- This function will throw an error if elements are of mismatching sizes. -- -- | @since 0.13.0.0 unsafeCast :: forall a b s. (HasCallStack, Prim a, Prim b) => MVector s a -> MVector s b {-# INLINE unsafeCast #-} unsafeCast (MVector o n ba) | sizeOf (undefined :: a) == sizeOf (undefined :: b) = MVector o n ba | otherwise = error "Element size mismatch"