Streamly.Internal.Data.Array.Mut.Type

Pinned and unpinned mutable array for Unboxed types. Fulfils the following goals:

• Random access (array)
• Efficient storage (unboxed)
• Performance (unboxed access)
• Performance - in-place operations (mutable)
• Performance - GC (pinned, mutable)
• interfacing with OS (pinned)

Stream and Fold APIs allow easy, efficient and convenient operations on arrays.

Mutable arrays and file system files are quite similar, they can grow and their content is mutable. Therefore, both have similar APIs as well. We strive to keep the API consistent for both. Ideally, you should be able to replace one with another with little changes to the code.

Type

We can use an Unboxed constraint in the MutArray type and the constraint can be automatically provided to a function that pattern matches on the MutArray type. However, it has huge performance cost, so we do not use it. Investigate a GHC improvement possiblity.

data MutArray a

An unboxed mutable array. An array is created with a given length and capacity. Length is the number of valid elements in the array. Capacity is the maximum number of elements that the array can be expanded to without having to reallocate the memory.

The elements in the array can be mutated in-place without changing the reference (constructor). However, the length of the array cannot be mutated in-place. A new array reference is generated when the length changes. When the length is increased (upto the maximum reserved capacity of the array), the array is not reallocated and the new reference uses the same underlying memory as the old one.

Several routines in this module allow the programmer to control the capacity of the array. The programmer can control the trade-off between memory usage and performance impact due to reallocations when growing or shrinking the array.

Constructors

MutArray

Fields

• arrContents :: !MutableByteArray
• arrStart :: !Int

  index into arrContents

• arrEnd :: !Int

  index into arrContents Represents the first invalid index of the array.

• arrBound :: !Int

  first invalid index of arrContents.

data MutableByteArray

touch :: MutableByteArray -> IO ()

pin :: MutArray a -> IO (MutArray a)

unpin :: MutArray a -> IO (MutArray a)

Constructing and Writing

Construction

nil :: MutArray a

Uninitialized Arrays

newPinned :: forall m a. (MonadIO m, Unbox a) => Int -> m (MutArray a)

Allocates an empty pinned array that can hold count items. The memory of the array is uninitialized and the allocation is aligned as per the Unboxed instance of the type.

newPinnedBytes :: MonadIO m => Int -> m (MutArray a)

Allocates a pinned empty array that can hold count items. The memory of the array is uninitialized and the allocation is aligned as per the Unboxed instance of the type.

Pre-release

newAlignedPinned :: (MonadIO m, Unbox a) => Int -> Int -> m (MutArray a)

Like newArrayWith but using an allocator is a pinned memory allocator and the alignment is dictated by the Unboxed instance of the type.

Internal

new :: (MonadIO m, Unbox a) => Int -> m (MutArray a)

Allocates an empty unpinned array that can hold count items. The memory of the array is uninitialized.

newArrayWith :: forall m a. (MonadIO m, Unbox a) => (Int -> Int -> m MutableByteArray) -> Int -> Int -> m (MutArray a)

newArrayWith allocator alignment count allocates a new array of zero length and with a capacity to hold count elements, using allocator size alignment as the memory allocator function.

Alignment must be greater than or equal to machine word size and a power of 2.

Alignment is ignored if the allocator allocates unpinned memory.

Pre-release

Initialized Arrays

withNewArrayUnsafe :: (MonadIO m, Unbox a) => Int -> (Ptr a -> m ()) -> m (MutArray a)

Allocate a pinned MutArray of the given size and run an IO action passing the array start pointer.

Internal

From streams

data ArrayUnsafe a

Constructors

ArrayUnsafe !MutableByteArray !Int !Int

writeNWithUnsafe :: forall m a. (MonadIO m, Unbox a) => (Int -> m (MutArray a)) -> Int -> Fold m a (MutArray a)

Like writeNUnsafe but takes a new array allocator alloc size function as argument.

>>> writeNWithUnsafe alloc n = MutArray.writeAppendNUnsafe (alloc n) n

Pre-release

writeNWith :: forall m a. (MonadIO m, Unbox a) => (Int -> m (MutArray a)) -> Int -> Fold m a (MutArray a)

writeNWith alloc n folds a maximum of n elements into an array allocated using the alloc function.

>>> writeNWith alloc n = Fold.take n (MutArray.writeNWithUnsafe alloc n)
>>> writeNWith alloc n = MutArray.writeAppendN (alloc n) n

writeNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (MutArray a)

Like writeN but does not check the array bounds when writing. The fold driver must not call the step function more than n times otherwise it will corrupt the memory and crash. This function exists mainly because any conditional in the step function blocks fusion causing 10x performance slowdown.

>>> writeNUnsafe = MutArray.writeNWithUnsafe MutArray.newPinned

writeN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (MutArray a)

writeN n folds a maximum of n elements from the input stream to an MutArray.

>>> writeN = MutArray.writeNWith MutArray.newPinned
>>> writeN n = Fold.take n (MutArray.writeNUnsafe n)
>>> writeN n = MutArray.writeAppendN n (MutArray.newPinned n)

writeNAligned :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> Fold m a (MutArray a)

writeNAligned align n folds a maximum of n elements from the input stream to a MutArray aligned to the given size.

>>> writeNAligned align = MutArray.writeNWith (MutArray.newAlignedPinned align)
>>> writeNAligned align n = MutArray.writeAppendN n (MutArray.newAlignedPinned align n)

Pre-release

writeWith :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (MutArray a)

writeWith minCount folds the whole input to a single array. The array starts at a size big enough to hold minCount elements, the size is doubled every time the array needs to be grown.

Caution! Do not use this on infinite streams.

>>> f n = MutArray.writeAppendWith (* 2) (MutArray.newPinned n)
>>> writeWith n = Fold.rmapM MutArray.rightSize (f n)
>>> writeWith n = Fold.rmapM MutArray.fromArrayStreamK (MutArray.writeChunks n)

Pre-release

write :: forall m a. (MonadIO m, Unbox a) => Fold m a (MutArray a)

Fold the whole input to a single array.

Same as writeWith using an initial array size of arrayChunkBytes bytes rounded up to the element size.

Caution! Do not use this on infinite streams.

writeRevN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (MutArray a)

Like writeN but writes the array in reverse order.

Pre-release

From containers

fromListN :: (MonadIO m, Unbox a) => Int -> [a] -> m (MutArray a)

Create a MutArray from the first N elements of a list. The array is allocated to size N, if the list terminates before N elements then the array may hold less than N elements.

fromList :: (MonadIO m, Unbox a) => [a] -> m (MutArray a)

Create a MutArray from a list. The list must be of finite size.

fromListRevN :: (MonadIO m, Unbox a) => Int -> [a] -> m (MutArray a)

Like fromListN but writes the array in reverse order.

Pre-release

fromListRev :: (MonadIO m, Unbox a) => [a] -> m (MutArray a)

Like fromList but writes the contents of the list in reverse order.

fromStreamDN :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> m (MutArray a)

Use the writeN fold instead.

>>> fromStreamDN n = Stream.fold (MutArray.writeN n)

fromStreamD :: (MonadIO m, Unbox a) => Stream m a -> m (MutArray a)

We could take the approach of doubling the memory allocation on each overflow. This would result in more or less the same amount of copying as in the chunking approach. However, if we have to shrink in the end then it may result in an extra copy of the entire data.

>>> fromStreamD = StreamD.fold MutArray.write

Random writes

putIndex :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> a -> m ()

O(1) Write the given element at the given index in the array. Performs in-place mutation of the array.

>>> putIndex ix arr val = MutArray.modifyIndex ix arr (const (val, ()))
>>> f = MutArray.putIndices
>>> putIndex ix arr val = Stream.fold (f arr) (Stream.fromPure (ix, val))

putIndexUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> a -> m ()

Write the given element to the given index of the array. Does not check if the index is out of bounds of the array.

Pre-release

putIndices :: forall m a. (MonadIO m, Unbox a) => MutArray a -> Fold m (Int, a) ()

Write an input stream of (index, value) pairs to an array. Throws an error if any index is out of bounds.

Pre-release

modifyIndexUnsafe :: forall m a b. (MonadIO m, Unbox a) => Int -> MutArray a -> (a -> (a, b)) -> m b

Modify a given index of an array using a modifier function.

Pre-release

modifyIndex :: forall m a b. (MonadIO m, Unbox a) => Int -> MutArray a -> (a -> (a, b)) -> m b

Modify a given index of an array using a modifier function.

Pre-release

modifyIndices :: forall m a. (MonadIO m, Unbox a) => MutArray a -> (Int -> a -> a) -> Fold m Int ()

Modify the array indices generated by the supplied stream.

Pre-release

modify :: forall m a. (MonadIO m, Unbox a) => MutArray a -> (a -> a) -> m ()

Modify each element of an array using the supplied modifier function.

Pre-release

swapIndices :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> MutArray a -> m ()

Swap the elements at two indices.

Pre-release

unsafeSwapIndices :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> MutArray a -> m ()

Swap the elements at two indices without validating the indices.

Unsafe: This could result in memory corruption if indices are not valid.

Pre-release

Growing and Shrinking

Appending elements

snocWith :: forall m a. (MonadIO m, Unbox a) => (Int -> Int) -> MutArray a -> a -> m (MutArray a)

snocWith sizer arr elem mutates arr to append elem. The length of the array increases by 1.

If there is no reserved space available in arr it is reallocated to a size in bytes determined by the sizer oldSizeBytes function, where oldSizeBytes is the original size of the array in bytes.

If the new array size is more than largeObjectThreshold we automatically round it up to blockSize.

Note that the returned array may be a mutated version of the original array.

Pre-release

snoc :: forall m a. (MonadIO m, Unbox a) => MutArray a -> a -> m (MutArray a)

The array is mutated to append an additional element to it. If there is no reserved space available in the array then it is reallocated to double the original size.

This is useful to reduce allocations when appending unknown number of elements.

Note that the returned array may be a mutated version of the original array.

>>> snoc = MutArray.snocWith (* 2)

Performs O(n * log n) copies to grow, but is liberal with memory allocation.

snocLinear :: forall m a. (MonadIO m, Unbox a) => MutArray a -> a -> m (MutArray a)

The array is mutated to append an additional element to it. If there is no reserved space available in the array then it is reallocated to grow it by arrayChunkBytes rounded up to blockSize when the size becomes more than largeObjectThreshold.

Note that the returned array may be a mutated version of the original array.

Performs O(n^2) copies to grow but is thrifty on memory.

Pre-release

snocMay :: forall m a. (MonadIO m, Unbox a) => MutArray a -> a -> m (Maybe (MutArray a))

Like snoc but does not reallocate when pre-allocated array capacity becomes full.

Internal

snocUnsafe :: forall m a. (MonadIO m, Unbox a) => MutArray a -> a -> m (MutArray a)

Really really unsafe, appends the element into the first array, may cause silent data corruption or if you are lucky a segfault if the first array does not have enough space to append the element.

Internal

Appending streams

writeAppendNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> m (MutArray a) -> Fold m a (MutArray a)

writeAppendNUnsafe n alloc appends up to n input items to the supplied array.

Unsafe: Do not drive the fold beyond n elements, it will lead to memory corruption or segfault.

Any free space left in the array after appending n elements is lost.

Internal

writeAppendN :: forall m a. (MonadIO m, Unbox a) => Int -> m (MutArray a) -> Fold m a (MutArray a)

Append n elements to an existing array. Any free space left in the array after appending n elements is lost.

>>> writeAppendN n initial = Fold.take n (MutArray.writeAppendNUnsafe n initial)

writeAppendWith :: forall m a. (MonadIO m, Unbox a) => (Int -> Int) -> m (MutArray a) -> Fold m a (MutArray a)

writeAppendWith realloc action mutates the array generated by action to append the input stream. If there is no reserved space available in the array it is reallocated to a size in bytes determined by realloc oldSize, where oldSize is the current size of the array in bytes.

Note that the returned array may be a mutated version of original array.

>>> writeAppendWith sizer = Fold.foldlM' (MutArray.snocWith sizer)

Pre-release

writeAppend :: forall m a. (MonadIO m, Unbox a) => m (MutArray a) -> Fold m a (MutArray a)

append action mutates the array generated by action to append the input stream. If there is no reserved space available in the array it is reallocated to double the size.

Note that the returned array may be a mutated version of original array.

>>> writeAppend = MutArray.writeAppendWith (* 2)

Eliminating and Reading

To streams

reader :: forall m a. (MonadIO m, Unbox a) => Unfold m (MutArray a) a

Unfold an array into a stream.

readerRevWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> Unfold m (MutArray a) a

readerRev :: forall m a. (MonadIO m, Unbox a) => Unfold m (MutArray a) a

Unfold an array into a stream in reverse order.

To containers

toStreamDWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> MutArray a -> Stream m a

toStreamDRevWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> MutArray a -> Stream m a

toStreamKWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> MutArray a -> StreamK m a

toStreamKRevWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> MutArray a -> StreamK m a

toStreamD :: forall m a. (MonadIO m, Unbox a) => MutArray a -> Stream m a

Use the reader unfold instead.

toStreamD = D.unfold reader

We can try this if the unfold has any performance issues.

toStreamDRev :: forall m a. (MonadIO m, Unbox a) => MutArray a -> Stream m a

Use the readerRev unfold instead.

toStreamDRev = D.unfold readerRev

We can try this if the unfold has any perf issues.

toStreamK :: forall m a. (MonadIO m, Unbox a) => MutArray a -> StreamK m a

toStreamKRev :: forall m a. (MonadIO m, Unbox a) => MutArray a -> StreamK m a

toList :: forall m a. (MonadIO m, Unbox a) => MutArray a -> m [a]

Convert a MutArray into a list.

producerWith :: forall m a. (Monad m, Unbox a) => (forall b. IO b -> m b) -> Producer m (MutArray a) a

producer :: forall m a. (MonadIO m, Unbox a) => Producer m (MutArray a) a

Resumable unfold of an array.

Random reads

getIndex :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m a

O(1) Lookup the element at the given index. Index starts from 0.

getIndexUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m a

Return the element at the specified index without checking the bounds.

Unsafe because it does not check the bounds of the array.

getIndices :: (MonadIO m, Unbox a) => Stream m Int -> Unfold m (MutArray a) a

getIndicesD :: (Monad m, Unbox a) => (forall b. IO b -> m b) -> Stream m Int -> Unfold m (MutArray a) a

Given an unfold that generates array indices, read the elements on those indices from the supplied MutArray. An error is thrown if an index is out of bounds.

Pre-release

getIndexRev :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m a

O(1) Lookup the element at the given index from the end of the array. Index starts from 0.

Slightly faster than computing the forward index and using getIndex.

Memory Management

blockSize :: Int

The page or block size used by the GHC allocator. Allocator allocates at least a block and then allocates smaller allocations from within a block.

arrayChunkBytes :: Int

The default chunk size by which the array creation routines increase the size of the array when the array is grown linearly.

allocBytesToElemCount :: Unbox a => a -> Int -> Int

Given an Unboxed type (unused first arg) and real allocation size (including overhead), return how many elements of that type will completely fit in it, returns at least 1.

realloc :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m (MutArray a)

realloc newCapacity array reallocates the array to the specified capacity in bytes.

If the new size is less than the original array the array gets truncated. If the new size is not a multiple of array element size then it is rounded down to multiples of array size. If the new size is more than largeObjectThreshold then it is rounded up to the block size (4K).

resize :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m (MutArray a)

resize newCapacity array changes the total capacity of the array so that it is enough to hold the specified number of elements. Nothing is done if the specified capacity is less than the length of the array.

If the capacity is more than largeObjectThreshold then it is rounded up to the block size (4K).

Pre-release

resizeExp :: forall m a. (MonadIO m, Unbox a) => Int -> MutArray a -> m (MutArray a)

Like resize but if the byte capacity is more than largeObjectThreshold then it is rounded up to the closest power of 2.

Pre-release

rightSize :: forall m a. (MonadIO m, Unbox a) => MutArray a -> m (MutArray a)

Resize the allocated memory to drop any reserved free space at the end of the array and reallocate it to reduce wastage.

Up to 25% wastage is allowed to avoid reallocations. If the capacity is more than largeObjectThreshold then free space up to the blockSize is retained.

Pre-release

Size

length :: forall a. Unbox a => MutArray a -> Int

O(1) Get the length of the array i.e. the number of elements in the array.

Note that byteLength is less expensive than this operation, as length involves a costly division operation.

byteLength :: MutArray a -> Int

O(1) Get the byte length of the array.

byteCapacity :: MutArray a -> Int

Get the total capacity of an array. An array may have space reserved beyond the current used length of the array.

Pre-release

bytesFree :: MutArray a -> Int

The remaining capacity in the array for appending more elements without reallocation.

Pre-release

In-place Mutation Algorithms

strip :: forall a m. (Unbox a, MonadIO m) => (a -> Bool) -> MutArray a -> m (MutArray a)

Strip elements which match with predicate from both ends.

Pre-release

reverse :: forall m a. (MonadIO m, Unbox a) => MutArray a -> m ()

You may not need to reverse an array because you can consume it in reverse using readerRev. To reverse large arrays you can read in reverse and write to another array. However, in-place reverse can be useful to take adavantage of cache locality and when you do not want to allocate additional memory.

permute :: MutArray a -> m Bool

Generate the next permutation of the sequence, returns False if this is the last permutation.

Unimplemented

partitionBy :: forall m a. (MonadIO m, Unbox a) => (a -> Bool) -> MutArray a -> m (MutArray a, MutArray a)

Partition an array into two halves using a partitioning predicate. The first half retains values where the predicate is False and the second half retains values where the predicate is True.

Pre-release

shuffleBy :: (a -> a -> m Bool) -> MutArray a -> MutArray a -> m ()

Shuffle corresponding elements from two arrays using a shuffle function. If the shuffle function returns False then do nothing otherwise swap the elements. This can be used in a bottom up fold to shuffle or reorder the elements.

Unimplemented

divideBy :: Int -> (MutArray a -> m (MutArray a, MutArray a)) -> MutArray a -> m ()

divideBy level partition array performs a top down hierarchical recursive partitioning fold of items in the container using the given function as the partition function. Level indicates the level in the tree where the fold would stop.

This performs a quick sort if the partition function is 'partitionBy (< pivot)'.

Unimplemented

mergeBy :: Int -> (MutArray a -> MutArray a -> m ()) -> MutArray a -> m ()

mergeBy level merge array performs a pairwise bottom up fold recursively merging the pairs using the supplied merge function. Level indicates the level in the tree where the fold would stop.

This performs a random shuffle if the merge function is random. If we stop at level 0 and repeatedly apply the function then we can do a bubble sort.

Unimplemented

bubble :: (MonadIO m, Unbox a) => (a -> a -> Ordering) -> MutArray a -> m ()

Given an array sorted in ascending order except the last element being out of order, use bubble sort to place the last element at the right place such that the array remains sorted in ascending order.

Pre-release

Casting

cast :: forall a b. Unbox b => MutArray a -> Maybe (MutArray b)

Cast an array having elements of type a into an array having elements of type b. The length of the array should be a multiple of the size of the target element otherwise Nothing is returned.

castUnsafe :: MutArray a -> MutArray b

Cast an array having elements of type a into an array having elements of type b. The array size must be a multiple of the size of type b otherwise accessing the last element of the array may result into a crash or a random value.

Pre-release

asBytes :: MutArray a -> MutArray Word8

Cast an MutArray a into an MutArray Word8.

asPtrUnsafe :: MonadIO m => MutArray a -> (Ptr a -> m b) -> m b

Use an MutArray a as Ptr a. This is useful when we want to pass an array as a pointer to some operating system call or to a "safe" FFI call.

If the array is not pinned it is copied to pinned memory before passing it to the monadic action.

Performance Notes: Forces a copy if the array is not pinned. It is advised that the programmer keeps this in mind and creates a pinned array opportunistically before this operation occurs, to avoid the cost of a copy if possible.

Unsafe

Pre-release

Folding

foldl' :: (MonadIO m, Unbox a) => (b -> a -> b) -> b -> MutArray a -> m b

Strict left fold of an array.

foldr :: (MonadIO m, Unbox a) => (a -> b -> b) -> b -> MutArray a -> m b

Right fold of an array.

cmp :: MonadIO m => MutArray a -> MutArray a -> m Ordering

Compare the length of the arrays. If the length is equal, compare the lexicographical ordering of two underlying byte arrays otherwise return the result of length comparison.

Pre-release

Arrays of arrays

Operations dealing with multiple arrays, streams of arrays or multidimensional array representations.

Construct from streams

chunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (MutArray a)

chunksOf n stream groups the input stream into a stream of arrays of size n.

chunksOf n = StreamD.foldMany (MutArray.writeN n)

Pre-release

arrayStreamKFromStreamD :: forall m a. (MonadIO m, Unbox a) => Stream m a -> m (StreamK m (MutArray a))

Buffer the stream into arrays in memory.

writeChunks :: (MonadIO m, Unbox a) => Int -> Fold m a (StreamK n (MutArray a))

Buffer a stream into a stream of arrays.

>>> writeChunks n = Fold.many (MutArray.writeN n) Fold.toStreamK

Breaking an array into an array stream can be useful to consume a large array sequentially such that memory of the array is released incrementatlly.

See also: arrayStreamKFromStreamD.

Unimplemented

Eliminate to streams

flattenArrays :: forall m a. (MonadIO m, Unbox a) => Stream m (MutArray a) -> Stream m a

Use the "reader" unfold instead.

flattenArrays = unfoldMany reader

We can try this if there are any fusion issues in the unfold.

flattenArraysRev :: forall m a. (MonadIO m, Unbox a) => Stream m (MutArray a) -> Stream m a

Use the "readerRev" unfold instead.

flattenArrays = unfoldMany readerRev

We can try this if there are any fusion issues in the unfold.

fromArrayStreamK :: (Unbox a, MonadIO m) => StreamK m (MutArray a) -> m (MutArray a)

Convert an array stream to an array. Note that this requires peak memory that is double the size of the array stream.

Construct from arrays

getSliceUnsafe

Arguments

:: forall a. Unbox a

=> Int

from index

-> Int

length of the slice

-> MutArray a

-> MutArray a

O(1) Slice an array in constant time.

Unsafe: The bounds of the slice are not checked.

Unsafe

Pre-release

getSlice

Arguments

:: forall a. Unbox a

=> Int

from index

-> Int

length of the slice

-> MutArray a

-> MutArray a

O(1) Slice an array in constant time. Throws an error if the slice extends out of the array bounds.

Pre-release

splitAt :: forall a. Unbox a => Int -> MutArray a -> (MutArray a, MutArray a)

Create two slices of an array without copying the original array. The specified index i is the first index of the second slice.

breakOn :: MonadIO m => Word8 -> MutArray Word8 -> m (MutArray Word8, Maybe (MutArray Word8))

Drops the separator byte

Appending arrays

spliceCopy :: forall m a. MonadIO m => MutArray a -> MutArray a -> m (MutArray a)

Copy two arrays into a newly allocated array.

spliceWith :: forall m a. (MonadIO m, Unbox a) => (Int -> Int -> Int) -> MutArray a -> MutArray a -> m (MutArray a)

spliceWith sizer dst src mutates dst to append src. If there is no reserved space available in dst it is reallocated to a size determined by the sizer dstBytes srcBytes function, where dstBytes is the size of the first array and srcBytes is the size of the second array, in bytes.

Note that the returned array may be a mutated version of first array.

Pre-release

splice :: (MonadIO m, Unbox a) => MutArray a -> MutArray a -> m (MutArray a)

The first array is mutated to append the second array. If there is no reserved space available in the first array a new allocation of exact required size is done.

Note that the returned array may be a mutated version of first array.

>>> splice = MutArray.spliceWith (+)

Pre-release

spliceExp :: (MonadIO m, Unbox a) => MutArray a -> MutArray a -> m (MutArray a)

Like append but the growth of the array is exponential. Whenever a new allocation is required the previous array size is at least doubled.

This is useful to reduce allocations when folding many arrays together.

Note that the returned array may be a mutated version of first array.

>>> spliceExp = MutArray.spliceWith (\l1 l2 -> max (l1 * 2) (l1 + l2))

Pre-release

spliceUnsafe :: MonadIO m => MutArray a -> MutArray a -> m (MutArray a)

Really really unsafe, appends the second array into the first array. If the first array does not have enough space it may cause silent data corruption or if you are lucky a segfault.

putSliceUnsafe :: MonadIO m => MutArray a -> Int -> MutArray a -> Int -> Int -> m ()

Put a sub range of a source array into a subrange of a destination array. This is not safe as it does not check the bounds.

Utilities

roundUpToPower2 :: Int -> Int

memcpy :: Ptr Word8 -> Ptr Word8 -> Int -> IO ()

memcmp :: Ptr Word8 -> Ptr Word8 -> Int -> IO Bool

c_memchr :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8)