Basement.Block.Mutable

A block of memory that contains elements of a type, very similar to an unboxed array but with the key difference:

• It doesn't have slicing capability (no cheap take or drop)
• It consume less memory: 1 Offset, 1 CountOf, 1 Pinning status trimmed
• It's unpackable in any constructor
• It uses unpinned memory by default

It should be rarely needed in high level API, but in lowlevel API or some data structure containing lots of unboxed array that will benefit from optimisation.

Because it's unpinned, the blocks are compactable / movable, at the expense of making them less friendly to interop with the C layer as address.

Note that sadly the bytearray primitive type automatically create a pinned bytearray if the size is bigger than a certain threshold

GHC Documentation associated:

includesrtsstorage/Block.h * LARGE_OBJECT_THRESHOLD ((uint32_t)(BLOCK_SIZE * 8 / 10)) * BLOCK_SIZE (1<<BLOCK_SHIFT)

includesrtsConstant.h * BLOCK_SHIFT 12

Documentation

data Block ty

A block of memory containing unpacked bytes representing values of type ty

Constructors

Block ByteArray#

Instances

PrimType ty => IsList (Block ty)

Associated Types

type Item (Block ty) :: *

Methods

fromList :: [Item (Block ty)] -> Block ty

fromListN :: Int -> [Item (Block ty)] -> Block ty

toList :: Block ty -> [Item (Block ty)]

(PrimType ty, Eq ty) => Eq (Block ty)

Methods

(==) :: Block ty -> Block ty -> Bool

(/=) :: Block ty -> Block ty -> Bool

Data ty => Data (Block ty)

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Block ty -> c (Block ty)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Block ty)

toConstr :: Block ty -> Constr

dataTypeOf :: Block ty -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c (Block ty))

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Block ty))

gmapT :: (forall b. Data b => b -> b) -> Block ty -> Block ty

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Block ty -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Block ty -> r

gmapQ :: (forall d. Data d => d -> u) -> Block ty -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Block ty -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Block ty -> m (Block ty)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Block ty -> m (Block ty)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Block ty -> m (Block ty)

(PrimType ty, Ord ty) => Ord (Block ty)

Methods

compare :: Block ty -> Block ty -> Ordering

(<) :: Block ty -> Block ty -> Bool

(<=) :: Block ty -> Block ty -> Bool

(>) :: Block ty -> Block ty -> Bool

(>=) :: Block ty -> Block ty -> Bool

max :: Block ty -> Block ty -> Block ty

min :: Block ty -> Block ty -> Block ty

(PrimType ty, Show ty) => Show (Block ty)

Methods

showsPrec :: Int -> Block ty -> ShowS

show :: Block ty -> String

showList :: [Block ty] -> ShowS

PrimType ty => Semigroup (Block ty)

Methods

(<>) :: Block ty -> Block ty -> Block ty

sconcat :: NonEmpty (Block ty) -> Block ty

stimes :: Integral b => b -> Block ty -> Block ty

PrimType ty => Monoid (Block ty)

Methods

mempty :: Block ty

mappend :: Block ty -> Block ty -> Block ty

mconcat :: [Block ty] -> Block ty

NormalForm (Block ty)

Methods

toNormalForm :: Block ty -> ()

Cast (Block a) (Block Word8)

Methods

cast :: Block a -> Block Word8

PrimType ty => From (Block ty) (UArray ty)

Methods

from :: Block ty -> UArray ty

PrimType ty => From (UArray ty) (Block ty)

Methods

from :: UArray ty -> Block ty

PrimType ty => From (Array ty) (Block ty)

Methods

from :: Array ty -> Block ty

(NatWithinBound (CountOf ty) n, KnownNat n, PrimType ty) => TryFrom (Block ty) (BlockN n ty)

Methods

tryFrom :: Block ty -> Maybe (BlockN n ty)

From (BlockN n ty) (Block ty)

Methods

from :: BlockN n ty -> Block ty

type Item (Block ty)

type Item (Block ty) = ty

data MutableBlock ty st

A Mutable block of memory containing unpacked bytes representing values of type ty

Constructors

MutableBlock (MutableByteArray# st)

mutableLengthSize :: PrimType ty => MutableBlock ty st -> CountOf ty

Deprecated: use mutableLength

mutableLength :: forall ty st. PrimType ty => MutableBlock ty st -> CountOf ty

Return the length of a Mutable Block

note: we don't allow resizing yet, so this can remain a pure function

mutableLengthBytes :: MutableBlock ty st -> CountOf Word8

mutableWithPtr :: PrimMonad prim => MutableBlock ty (PrimState prim) -> (Ptr ty -> prim a) -> prim a

Deprecated: use withMutablePtr

Use the Ptr to a mutable block in a safer construct

If the block is not pinned, this is a _dangerous_ operation

withMutablePtr :: PrimMonad prim => MutableBlock ty (PrimState prim) -> (Ptr ty -> prim a) -> prim a

Create a pointer on the beginning of the MutableBlock and call a function f.

The mutable block can be mutated by the f function and the change will be reflected in the mutable block

If the mutable block is unpinned, a trampoline buffer is created and the data is only copied when f return.

it is all-in-all highly inefficient as this cause 2 copies

withMutablePtrHint

Arguments

:: PrimMonad prim

=> Bool

hint that the buffer doesn't need to have the same value as the mutable block when calling f

-> Bool

hint that the buffer is not supposed to be modified by call of f

-> MutableBlock ty (PrimState prim)

-> (Ptr ty -> prim a)

-> prim a

Same as withMutablePtr but allow to specify 2 optimisations which is only useful when the MutableBlock is unpinned and need a pinned trampoline to be called safely.

If skipCopy is True, then the first copy which happen before the call to f, is skipped. The Ptr is now effectively pointing to uninitialized data in a new mutable Block.

If skipCopyBack is True, then the second copy which happen after the call to f, is skipped. Then effectively in the case of a trampoline being used the memory changed by f will not be reflected in the original Mutable Block.

If using the wrong parameters, it will lead to difficult to debug issue of corrupted buffer which only present themselves with certain Mutable Block that happened to have been allocated unpinned.

If unsure use withMutablePtr, which default to *not* skip any copy.

new :: forall prim ty. (PrimMonad prim, PrimType ty) => CountOf ty -> prim (MutableBlock ty (PrimState prim))

Create a new unpinned mutable block of a specific N size of ty elements

If the size exceeds a GHC-defined threshold, then the memory will be pinned. To be certain about pinning status with small size, use newPinned

newPinned :: forall prim ty. (PrimMonad prim, PrimType ty) => CountOf ty -> prim (MutableBlock ty (PrimState prim))

Create a new pinned mutable block of a specific N size of ty elements

mutableEmpty :: PrimMonad prim => prim (MutableBlock ty (PrimState prim))

iterSet :: (PrimType ty, PrimMonad prim) => (Offset ty -> ty) -> MutableBlock ty (PrimState prim) -> prim ()

Set all mutable block element to a value

read :: (PrimMonad prim, PrimType ty) => MutableBlock ty (PrimState prim) -> Offset ty -> prim ty

read a cell in a mutable array.

If the index is out of bounds, an error is raised.

write :: (PrimMonad prim, PrimType ty) => MutableBlock ty (PrimState prim) -> Offset ty -> ty -> prim ()

Write to a cell in a mutable array.

If the index is out of bounds, an error is raised.

unsafeNew :: PrimMonad prim => PinnedStatus -> CountOf Word8 -> prim (MutableBlock ty (PrimState prim))

Create a new mutable block of a specific size in bytes.

Note that no checks are made to see if the size in bytes is compatible with the size of the underlaying element ty in the block.

use new if unsure

unsafeWrite :: (PrimMonad prim, PrimType ty) => MutableBlock ty (PrimState prim) -> Offset ty -> ty -> prim ()

write to a cell in a mutable block without bounds checking.

Writing with invalid bounds will corrupt memory and your program will become unreliable. use write if unsure.

unsafeRead :: (PrimMonad prim, PrimType ty) => MutableBlock ty (PrimState prim) -> Offset ty -> prim ty

read from a cell in a mutable block without bounds checking.

Reading from invalid memory can return unpredictable and invalid values. use read if unsure.

unsafeFreeze :: PrimMonad prim => MutableBlock ty (PrimState prim) -> prim (Block ty)

Freeze a mutable block into a block.

If the mutable block is still use after freeze, then the modification will be reflected in an unexpected way in the Block.

unsafeThaw :: (PrimType ty, PrimMonad prim) => Block ty -> prim (MutableBlock ty (PrimState prim))

Thaw an immutable block.

If the immutable block is modified, then the original immutable block will be modified too, but lead to unexpected results when querying

unsafeCopyElements

Arguments

:: (PrimMonad prim, PrimType ty)

=> MutableBlock ty (PrimState prim)

destination mutable block

-> Offset ty

offset at destination

-> MutableBlock ty (PrimState prim)

source mutable block

-> Offset ty

offset at source

-> CountOf ty

number of elements to copy

-> prim ()

Copy a number of elements from an array to another array with offsets

unsafeCopyElementsRO

Arguments

:: (PrimMonad prim, PrimType ty)

=> MutableBlock ty (PrimState prim)

destination mutable block

-> Offset ty

offset at destination

-> Block ty

source block

-> Offset ty

offset at source

-> CountOf ty

number of elements to copy

-> prim ()

unsafeCopyBytes

Arguments

:: PrimMonad prim

=> MutableBlock ty (PrimState prim)

destination mutable block

-> Offset Word8

offset at destination

-> MutableBlock ty (PrimState prim)

source mutable block

-> Offset Word8

offset at source

-> CountOf Word8

number of elements to copy

-> prim ()

Copy a number of bytes from a MutableBlock to another MutableBlock with specific byte offsets

unsafeCopyBytesRO

Arguments

:: PrimMonad prim

=> MutableBlock ty (PrimState prim)

destination mutable block

-> Offset Word8

offset at destination

-> Block ty

source block

-> Offset Word8

offset at source

-> CountOf Word8

number of elements to copy

-> prim ()

Copy a number of bytes from a Block to a MutableBlock with specific byte offsets

unsafeCopyBytesPtr

Arguments

:: PrimMonad prim

=> MutableBlock ty (PrimState prim)

destination mutable block

-> Offset Word8

offset at destination

-> Ptr ty

source block

-> CountOf Word8

number of bytes to copy

-> prim ()

Copy a number of bytes from a Ptr to a MutableBlock with specific byte offsets

Foreign

copyFromPtr

Arguments

:: (PrimMonad prim, PrimType ty)

=> Ptr ty

Source Ptr of ty to start of memory

-> MutableBlock ty (PrimState prim)

Destination mutable block

-> Offset ty

Start offset in the destination mutable block

-> CountOf ty

Number of ty elements

-> prim ()

Copy from a pointer, count elements, into the Mutable Block at a starting offset ofs

if the source pointer is invalid (size or bad allocation), bad things will happen

copyToPtr

Arguments

:: (PrimType ty, PrimMonad prim)

=> MutableBlock ty (PrimState prim)

The source mutable block to copy

-> Offset ty

The source offset in the mutable block

-> Ptr ty

The destination address where the copy is going to start

-> CountOf ty

The number of bytes

-> prim ()

Copy all the block content to the memory starting at the destination address

If the destination pointer is invalid (size or bad allocation), bad things will happen