Data.Primitive.ByteArray

Primitive operations on byte arrays. Most functions in this module include an element type in their type signature and interpret the unit for offsets and lengths as that element. A few functions (e.g. copyByteArray, freezeByteArray) do not include an element type. Such functions interpret offsets and lengths as units of 8-bit words.

Types

data ByteArray

Boxed wrapper for ByteArray#.

Since ByteArray# is an unlifted type and not a member of kind Type, things like [ByteArray#] or IO ByteArray# are ill-typed. To work around this inconvenience this module provides a standard boxed wrapper, inhabiting Type. Clients are expected to use ByteArray in higher-level APIs, but wrap and unwrap ByteArray internally as they please and use functions from GHC.Exts.

Constructors

ByteArray ByteArray#

Instances

Data ByteArray

Defined in Data.Array.Byte

Methods

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

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

toConstr :: ByteArray -> Constr

dataTypeOf :: ByteArray -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ByteArray)

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

gmapT :: (forall b. Data b => b -> b) -> ByteArray -> ByteArray

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

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

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

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

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

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

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

Monoid ByteArray

Defined in Data.Array.Byte

Methods

mempty :: ByteArray

mappend :: ByteArray -> ByteArray -> ByteArray

mconcat :: [ByteArray] -> ByteArray

Semigroup ByteArray

Defined in Data.Array.Byte

Methods

(<>) :: ByteArray -> ByteArray -> ByteArray

sconcat :: NonEmpty ByteArray -> ByteArray

stimes :: Integral b => b -> ByteArray -> ByteArray

IsList ByteArray

Defined in Data.Array.Byte

Associated Types

type Item ByteArray

Methods

fromList :: [Item ByteArray] -> ByteArray

fromListN :: Int -> [Item ByteArray] -> ByteArray

toList :: ByteArray -> [Item ByteArray]

Show ByteArray

Defined in Data.Array.Byte

Methods

showsPrec :: Int -> ByteArray -> ShowS

show :: ByteArray -> String

showList :: [ByteArray] -> ShowS

NFData ByteArray

Defined in Data.Array.Byte

Methods

rnf :: ByteArray -> ()

Eq ByteArray

Defined in Data.Array.Byte

Methods

(==) :: ByteArray -> ByteArray -> Bool

(/=) :: ByteArray -> ByteArray -> Bool

Ord ByteArray

Non-lexicographic ordering. This compares the lengths of the byte arrays first and uses a lexicographic ordering if the lengths are equal. Subject to change between major versions.

Defined in Data.Array.Byte

Methods

compare :: ByteArray -> ByteArray -> Ordering

(<) :: ByteArray -> ByteArray -> Bool

(<=) :: ByteArray -> ByteArray -> Bool

(>) :: ByteArray -> ByteArray -> Bool

(>=) :: ByteArray -> ByteArray -> Bool

max :: ByteArray -> ByteArray -> ByteArray

min :: ByteArray -> ByteArray -> ByteArray

Lift ByteArray

Defined in Data.Array.Byte

Methods

lift :: Quote m => ByteArray -> m Exp

liftTyped :: forall (m :: Type -> Type). Quote m => ByteArray -> Code m ByteArray

type Item ByteArray

Defined in Data.Array.Byte

type Item ByteArray = Word8

data MutableByteArray s

Boxed wrapper for MutableByteArray#.

Since MutableByteArray# is an unlifted type and not a member of kind Type, things like [MutableByteArray#] or IO MutableByteArray# are ill-typed. To work around this inconvenience this module provides a standard boxed wrapper, inhabiting Type. Clients are expected to use MutableByteArray in higher-level APIs, but wrap and unwrap MutableByteArray internally as they please and use functions from GHC.Exts.

Constructors

MutableByteArray (MutableByteArray# s)

Instances

Typeable s => Data (MutableByteArray s)

Defined in Data.Array.Byte

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> MutableByteArray s -> c (MutableByteArray s)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (MutableByteArray s)

toConstr :: MutableByteArray s -> Constr

dataTypeOf :: MutableByteArray s -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (MutableByteArray s))

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (MutableByteArray s))

gmapT :: (forall b. Data b => b -> b) -> MutableByteArray s -> MutableByteArray s

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> MutableByteArray s -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> MutableByteArray s -> r

gmapQ :: (forall d. Data d => d -> u) -> MutableByteArray s -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> MutableByteArray s -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> MutableByteArray s -> m (MutableByteArray s)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> MutableByteArray s -> m (MutableByteArray s)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> MutableByteArray s -> m (MutableByteArray s)

NFData (MutableByteArray s)

Defined in Data.Array.Byte

Methods

rnf :: MutableByteArray s -> ()

Eq (MutableByteArray s)

Defined in Data.Array.Byte

Methods

(==) :: MutableByteArray s -> MutableByteArray s -> Bool

(/=) :: MutableByteArray s -> MutableByteArray s -> Bool

data ByteArray# :: UnliftedType

A boxed, unlifted datatype representing a region of raw memory in the garbage-collected heap, which is not scanned for pointers during garbage collection.

It is created by freezing a 'MutableByteArray#' with 'unsafeFreezeByteArray#'. Freezing is essentially a no-op, as MutableByteArray# and ByteArray# share the same heap structure under the hood.

The immutable and mutable variants are commonly used for scenarios requiring high-performance data structures, like Text, Primitive Vector, Unboxed Array, and ShortByteString.

Another application of fundamental importance is 'Integer', which is backed by 'ByteArray#'.

The representation on the heap of a Byte Array is:

+------------+-----------------+-----------------------+
|            |                 |                       |
|   HEADER   | SIZE (in bytes) |       PAYLOAD         |
|            |                 |                       |
+------------+-----------------+-----------------------+

To obtain a pointer to actual payload (e.g., for FFI purposes) use 'byteArrayContents#' or 'mutableByteArrayContents#'.

Alternatively, enabling the UnliftedFFITypes extension allows to mention 'ByteArray#' and 'MutableByteArray#' in FFI type signatures directly.

data MutableByteArray# a :: UnliftedType

A mutable ByteAray#. It can be created in three ways:

• 'newByteArray#': Create an unpinned array.
• 'newPinnedByteArray#': This will create a pinned array,
• 'newAlignedPinnedByteArray#': This will create a pinned array, with a custom alignment.

Unpinned arrays can be moved around during garbage collection, so you must not store or pass pointers to these values if there is a chance for the garbage collector to kick in. That said, even unpinned arrays can be passed to unsafe FFI calls, because no garbage collection happens during these unsafe calls (see Guaranteed Call Safety in the GHC Manual). For safe FFI calls, byte arrays must be not only pinned, but also kept alive by means of the keepAlive# function for the duration of a call (that's because garbage collection cannot move a pinned array, but is free to scrap it altogether).

Allocation

newByteArray :: PrimMonad m => Int -> m (MutableByteArray (PrimState m))

Create a new mutable byte array of the specified size in bytes. The underlying memory is left uninitialized.

Note: this function does not check if the input is non-negative.

newPinnedByteArray :: PrimMonad m => Int -> m (MutableByteArray (PrimState m))

Create a pinned byte array of the specified size in bytes. The garbage collector is guaranteed not to move it. The underlying memory is left uninitialized.

Note: this function does not check if the input is non-negative.

newAlignedPinnedByteArray

Arguments

:: PrimMonad m

=> Int

size

-> Int

alignment

-> m (MutableByteArray (PrimState m))

Create a pinned byte array of the specified size in bytes and with the given alignment. The garbage collector is guaranteed not to move it. The underlying memory is left uninitialized.

Note: this function does not check if the input is non-negative.

resizeMutableByteArray :: PrimMonad m => MutableByteArray (PrimState m) -> Int -> m (MutableByteArray (PrimState m))

Resize a mutable byte array. The new size is given in bytes.

This will either resize the array in-place or, if not possible, allocate the contents into a new, unpinned array and copy the original array's contents.

To avoid undefined behaviour, the original MutableByteArray shall not be accessed anymore after a resizeMutableByteArray has been performed. Moreover, no reference to the old one should be kept in order to allow garbage collection of the original MutableByteArray in case a new MutableByteArray had to be allocated.

Since: 0.6.4.0

shrinkMutableByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

-> Int

new size

-> m ()

Shrink a mutable byte array. The new size is given in bytes. It must be smaller than the old size. The array will be resized in place.

Since: 0.7.1.0

Element access

readByteArray :: (Prim a, PrimMonad m) => MutableByteArray (PrimState m) -> Int -> m a

Read a primitive value from the byte array. The offset is given in elements of type a rather than in bytes.

Note: this function does not do bounds checking.

writeByteArray :: (Prim a, PrimMonad m) => MutableByteArray (PrimState m) -> Int -> a -> m ()

Write a primitive value to the byte array. The offset is given in elements of type a rather than in bytes.

Note: this function does not do bounds checking.

indexByteArray :: Prim a => ByteArray -> Int -> a

Read a primitive value from the byte array. The offset is given in elements of type a rather than in bytes.

Note: this function does not do bounds checking.

Char Element Access

GHC provides two sets of element accessors for Char. One set faithfully represents Char as 32-bit words using UTF-32. The other set represents Char as 8-bit words using Latin-1 (ISO-8859-1), and the write operation has undefined behavior for codepoints outside of the ASCII and Latin-1 blocks. The Prim instance for Char uses the UTF-32 set of operators.

readCharArray :: PrimMonad m => MutableByteArray (PrimState m) -> Int -> m Char

Read an 8-bit element from the byte array, interpreting it as a Latin-1-encoded character. The offset is given in bytes.

Note: this function does not do bounds checking.

writeCharArray :: PrimMonad m => MutableByteArray (PrimState m) -> Int -> Char -> m ()

Write a character to the byte array, encoding it with Latin-1 as a single byte. Behavior is undefined for codepoints outside of the ASCII and Latin-1 blocks. The offset is given in bytes.

Note: this function does not do bounds checking.

indexCharArray :: ByteArray -> Int -> Char

Read an 8-bit element from the byte array, interpreting it as a Latin-1-encoded character. The offset is given in bytes.

Note: this function does not do bounds checking.

Constructing

emptyByteArray :: ByteArray

The empty ByteArray.

byteArrayFromList :: Prim a => [a] -> ByteArray

Create a ByteArray from a list.

byteArrayFromList xs = byteArrayFromListN (length xs) xs

byteArrayFromListN :: forall a. Prim a => Int -> [a] -> ByteArray

Create a ByteArray from a list of a known length. If the length of the list does not match the given length, this throws an exception.

Folding

foldrByteArray :: forall a b. Prim a => (a -> b -> b) -> b -> ByteArray -> b

Right-fold over the elements of a ByteArray.

Comparing

compareByteArrays

Arguments

:: ByteArray

array A

-> Int

offset A, given in bytes

-> ByteArray

array B

-> Int

offset B, given in bytes

-> Int

length of the slice, given in bytes

-> Ordering

Lexicographic comparison of equal-length slices into two byte arrays. This wraps the compareByteArrays# primop, which wraps memcmp.

Freezing and thawing

freezeByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

source

-> Int

offset in bytes

-> Int

length in bytes

-> m ByteArray

Create an immutable copy of a slice of a byte array. The offset and length are given in bytes.

This operation makes a copy of the specified section, so it is safe to continue using the mutable array afterward.

Note: The provided array should contain the full subrange specified by the two Ints, but this is not checked.

thawByteArray

Arguments

:: PrimMonad m

=> ByteArray

source

-> Int

offset in bytes

-> Int

length in bytes

-> m (MutableByteArray (PrimState m))

Create a mutable byte array from a slice of an immutable byte array. The offset and length are given in bytes.

This operation makes a copy of the specified slice, so it is safe to use the immutable array afterward.

Note: The provided array should contain the full subrange specified by the two Ints, but this is not checked.

Since: 0.7.2.0

runByteArray :: (forall s. ST s (MutableByteArray s)) -> ByteArray

Execute the monadic action and freeze the resulting array.

runByteArray m = runST $ m >>= unsafeFreezeByteArray

unsafeFreezeByteArray :: PrimMonad m => MutableByteArray (PrimState m) -> m ByteArray

Convert a mutable byte array to an immutable one without copying. The array should not be modified after the conversion.

unsafeThawByteArray :: PrimMonad m => ByteArray -> m (MutableByteArray (PrimState m))

Convert an immutable byte array to a mutable one without copying. The original array should not be used after the conversion.

Block operations

copyByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

destination array

-> Int

offset into destination array

-> ByteArray

source array

-> Int

offset into source array

-> Int

number of bytes to copy

-> m ()

Copy a slice of an immutable byte array to a mutable byte array.

Note: this function does not do bounds or overlap checking.

copyMutableByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

destination array

-> Int

offset into destination array

-> MutableByteArray (PrimState m)

source array

-> Int

offset into source array

-> Int

number of bytes to copy

-> m ()

Copy a slice of a mutable byte array into another array. The two slices may not overlap.

Note: this function does not do bounds or overlap checking.

copyByteArrayToPtr

Arguments

:: forall m a. (PrimMonad m, Prim a)

=> Ptr a

destination

-> ByteArray

source array

-> Int

offset into source array, interpreted as elements of type a

-> Int

number of elements to copy

-> m ()

Copy a slice of a byte array to an unmanaged pointer address. These must not overlap. The offset and length are given in elements, not in bytes.

Note: this function does not do bounds or overlap checking.

Since: 0.7.1.0

copyMutableByteArrayToPtr

Arguments

:: forall m a. (PrimMonad m, Prim a)

=> Ptr a

destination

-> MutableByteArray (PrimState m)

source array

-> Int

offset into source array, interpreted as elements of type a

-> Int

number of elements to copy

-> m ()

Copy a slice of a mutable byte array to an unmanaged pointer address. These must not overlap. The offset and length are given in elements, not in bytes.

Note: this function does not do bounds or overlap checking.

Since: 0.7.1.0

copyByteArrayToAddr

Arguments

:: PrimMonad m

=> Ptr Word8

destination

-> ByteArray

source array

-> Int

offset into source array

-> Int

number of bytes to copy

-> m ()

Copy a slice of a byte array to an unmanaged address. These must not overlap.

Note: This function is just copyByteArrayToPtr where a is Word8.

Since: 0.6.4.0

copyMutableByteArrayToAddr

Arguments

:: PrimMonad m

=> Ptr Word8

destination

-> MutableByteArray (PrimState m)

source array

-> Int

offset into source array

-> Int

number of bytes to copy

-> m ()

Copy a slice of a mutable byte array to an unmanaged address. These must not overlap.

Note: This function is just copyMutableByteArrayToPtr where a is Word8.

Since: 0.6.4.0

copyPtrToMutableByteArray

Arguments

:: forall m a. (PrimMonad m, Prim a)

=> MutableByteArray (PrimState m)

destination array

-> Int

destination offset given in elements of type a

-> Ptr a

source pointer

-> Int

number of elements

-> m ()

Copy from an unmanaged pointer address to a byte array. These must not overlap. The offset and length are given in elements, not in bytes.

Note: this function does not do bounds or overlap checking.

moveByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

destination array

-> Int

offset into destination array

-> MutableByteArray (PrimState m)

source array

-> Int

offset into source array

-> Int

number of bytes to copy

-> m ()

Copy a slice of a mutable byte array into another, potentially overlapping array.

setByteArray

Arguments

:: (Prim a, PrimMonad m)

=> MutableByteArray (PrimState m)

array to fill

-> Int

offset into array

-> Int

number of values to fill

-> a

value to fill with

-> m ()

Fill a slice of a mutable byte array with a value. The offset and length are given in elements of type a rather than in bytes.

Note: this function does not do bounds checking.

fillByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

array to fill

-> Int

offset into array

-> Int

number of bytes to fill

-> Word8

byte to fill with

-> m ()

Fill a slice of a mutable byte array with a byte.

Note: this function does not do bounds checking.

cloneByteArray

Arguments

:: ByteArray

source array

-> Int

offset into destination array

-> Int

number of bytes to copy

-> ByteArray

Return a newly allocated array with the specified subrange of the provided array. The provided array should contain the full subrange specified by the two Ints, but this is not checked.

cloneMutableByteArray

Arguments

:: PrimMonad m

=> MutableByteArray (PrimState m)

source array

-> Int

offset into destination array

-> Int

number of bytes to copy

-> m (MutableByteArray (PrimState m))

Return a newly allocated mutable array with the specified subrange of the provided mutable array. The provided mutable array should contain the full subrange specified by the two Ints, but this is not checked.

Information

sizeofByteArray :: ByteArray -> Int

Size of the byte array in bytes.

sizeofMutableByteArray :: MutableByteArray s -> Int

Deprecated: use getSizeofMutableByteArray instead

Size of the mutable byte array in bytes.

This function is deprecated and will be removed. Its behavior is undefined if resizeMutableByteArray is ever called on the mutable byte array given as the argument. Prefer getSizeofMutableByteArray, which ensures correct sequencing in the presence of resizing.

getSizeofMutableByteArray :: PrimMonad m => MutableByteArray (PrimState m) -> m Int

Get the size of a byte array in bytes. Unlike sizeofMutableByteArray, this function ensures sequencing in the presence of resizing.

sameMutableByteArray :: MutableByteArray s -> MutableByteArray s -> Bool

Check if the two arrays refer to the same memory block.

isByteArrayPinned :: ByteArray -> Bool

Check whether or not the byte array is pinned. Pinned byte arrays cannot be moved by the garbage collector. It is safe to use byteArrayContents on such byte arrays.

Caution: This function is only available when compiling with GHC 8.2 or newer.

Since: 0.6.4.0

isMutableByteArrayPinned :: MutableByteArray s -> Bool

Check whether or not the mutable byte array is pinned.

Caution: This function is only available when compiling with GHC 8.2 or newer.

Since: 0.6.4.0

byteArrayContents :: ByteArray -> Ptr Word8

Yield a pointer to the array's data. This operation is only safe on pinned byte arrays. Byte arrays allocated by newPinnedByteArray and newAlignedPinnedByteArray are guaranteed to be pinned. Byte arrays allocated by newByteArray may or may not be pinned (use isByteArrayPinned to figure out).

Prefer withByteArrayContents, which ensures that the array is not garbage collected while the pointer is being used.

withByteArrayContents :: PrimBase m => ByteArray -> (Ptr Word8 -> m a) -> m a

A composition of byteArrayContents and keepAliveUnlifted. The callback function must not return the pointer. The argument byte array must be pinned. See byteArrayContents for an explanation of which byte arrays are pinned.

Note: This could be implemented with keepAlive instead of keepAliveUnlifted, but keepAlive here would cause GHC to materialize the wrapper data constructor on the heap.

mutableByteArrayContents :: MutableByteArray s -> Ptr Word8

Yield a pointer to the array's data. This operation is only safe on pinned byte arrays. See byteArrayContents for an explanation of which byte arrays are pinned.

Prefer withByteArrayContents, which ensures that the array is not garbage collected while the pointer is being used.

withMutableByteArrayContents :: PrimBase m => MutableByteArray (PrimState m) -> (Ptr Word8 -> m a) -> m a

A composition of mutableByteArrayContents and keepAliveUnlifted. The callback function must not return the pointer. The argument byte array must be pinned. See byteArrayContents for an explanation of which byte arrays are pinned.