Copyright | (c) 2019 Composewell Technologies |
---|---|
License | BSD3 |
Maintainer | streamly@composewell.com |
Stability | experimental |
Portability | GHC |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
Synopsis
- data Array a = Array {
- arrContents :: !MutByteArray
- arrStart :: !Int
- arrEnd :: !Int
- asPtrUnsafe :: MonadIO m => Array a -> (Ptr a -> m b) -> m b
- nil :: Array a
- unsafeFreeze :: MutArray a -> Array a
- unsafeFreezeWithShrink :: Unbox a => MutArray a -> Array a
- unsafeThaw :: Array a -> MutArray a
- pin :: Array a -> IO (Array a)
- unpin :: Array a -> IO (Array a)
- isPinned :: Array a -> Bool
- splice :: (MonadIO m, Unbox a) => Array a -> Array a -> m (Array a)
- fromList :: Unbox a => [a] -> Array a
- pinnedFromList :: Unbox a => [a] -> Array a
- fromListN :: Unbox a => Int -> [a] -> Array a
- pinnedFromListN :: Unbox a => Int -> [a] -> Array a
- fromListRev :: Unbox a => [a] -> Array a
- fromListRevN :: Unbox a => Int -> [a] -> Array a
- fromStreamDN :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> m (Array a)
- fromStreamD :: forall m a. (MonadIO m, Unbox a) => Stream m a -> m (Array a)
- fromPureStream :: Unbox a => Stream Identity a -> Array a
- fromByteStr# :: Addr# -> Array Word8
- breakOn :: MonadIO m => Word8 -> Array Word8 -> m (Array Word8, Maybe (Array Word8))
- clone :: MonadIO m => Array a -> m (Array a)
- pinnedClone :: MonadIO m => Array a -> m (Array a)
- unsafeIndexIO :: forall a. Unbox a => Int -> Array a -> IO a
- getIndexUnsafe :: forall a. Unbox a => Int -> Array a -> a
- byteLength :: Array a -> Int
- length :: Unbox a => Array a -> Int
- foldl' :: forall a b. Unbox a => (b -> a -> b) -> b -> Array a -> b
- foldr :: Unbox a => (a -> b -> b) -> b -> Array a -> b
- splitAt :: Unbox a => Int -> Array a -> (Array a, Array a)
- toStreamD :: forall m a. (Monad m, Unbox a) => Array a -> Stream m a
- toStreamDRev :: forall m a. (Monad m, Unbox a) => Array a -> Stream m a
- toStreamK :: forall m a. (Monad m, Unbox a) => Array a -> StreamK m a
- toStreamKRev :: forall m a. (Monad m, Unbox a) => Array a -> StreamK m a
- toStream :: (Monad m, Unbox a) => Array a -> Stream m a
- toStreamRev :: (Monad m, Unbox a) => Array a -> Stream m a
- read :: (Monad m, Unbox a) => Array a -> Stream m a
- readRev :: (Monad m, Unbox a) => Array a -> Stream m a
- readerRev :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a
- toList :: Unbox a => Array a -> [a]
- writeWith :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- writeN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- pinnedWriteN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- writeNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- pinnedWriteNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- data ArrayUnsafe a = ArrayUnsafe !MutByteArray !Int !Int
- pinnedWriteNAligned :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> Fold m a (Array a)
- write :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a)
- pinnedWrite :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a)
- unsafeMakePure :: Monad m => Fold IO a b -> Fold m a b
- chunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a)
- pinnedChunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a)
- bufferChunks :: (MonadIO m, Unbox a) => Stream m a -> m (StreamK m (Array a))
- flattenArrays :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a
- flattenArraysRev :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a
- unsafeIndex :: forall a. Unbox a => Int -> Array a -> a
- data Array a = Array {
- arrContents :: !MutByteArray
- arrStart :: !Int
- arrEnd :: !Int
- asPtrUnsafe :: MonadIO m => Array a -> (Ptr a -> m b) -> m b
- nil :: Array a
- unsafeFreeze :: MutArray a -> Array a
- unsafeFreezeWithShrink :: Unbox a => MutArray a -> Array a
- unsafeThaw :: Array a -> MutArray a
- pin :: Array a -> IO (Array a)
- unpin :: Array a -> IO (Array a)
- isPinned :: Array a -> Bool
- splice :: (MonadIO m, Unbox a) => Array a -> Array a -> m (Array a)
- fromList :: Unbox a => [a] -> Array a
- pinnedFromList :: Unbox a => [a] -> Array a
- fromListN :: Unbox a => Int -> [a] -> Array a
- pinnedFromListN :: Unbox a => Int -> [a] -> Array a
- fromListRev :: Unbox a => [a] -> Array a
- fromListRevN :: Unbox a => Int -> [a] -> Array a
- fromStreamDN :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> m (Array a)
- fromStreamD :: forall m a. (MonadIO m, Unbox a) => Stream m a -> m (Array a)
- fromPureStream :: Unbox a => Stream Identity a -> Array a
- fromByteStr# :: Addr# -> Array Word8
- breakOn :: MonadIO m => Word8 -> Array Word8 -> m (Array Word8, Maybe (Array Word8))
- clone :: MonadIO m => Array a -> m (Array a)
- pinnedClone :: MonadIO m => Array a -> m (Array a)
- unsafeIndexIO :: forall a. Unbox a => Int -> Array a -> IO a
- getIndexUnsafe :: forall a. Unbox a => Int -> Array a -> a
- byteLength :: Array a -> Int
- length :: Unbox a => Array a -> Int
- foldl' :: forall a b. Unbox a => (b -> a -> b) -> b -> Array a -> b
- foldr :: Unbox a => (a -> b -> b) -> b -> Array a -> b
- splitAt :: Unbox a => Int -> Array a -> (Array a, Array a)
- toStreamD :: forall m a. (Monad m, Unbox a) => Array a -> Stream m a
- toStreamDRev :: forall m a. (Monad m, Unbox a) => Array a -> Stream m a
- toStreamK :: forall m a. (Monad m, Unbox a) => Array a -> StreamK m a
- toStreamKRev :: forall m a. (Monad m, Unbox a) => Array a -> StreamK m a
- toStream :: (Monad m, Unbox a) => Array a -> Stream m a
- toStreamRev :: (Monad m, Unbox a) => Array a -> Stream m a
- read :: (Monad m, Unbox a) => Array a -> Stream m a
- readRev :: (Monad m, Unbox a) => Array a -> Stream m a
- readerRev :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a
- toList :: Unbox a => Array a -> [a]
- writeWith :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- writeN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- pinnedWriteN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- writeNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- pinnedWriteNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- data ArrayUnsafe a = ArrayUnsafe !MutByteArray !Int !Int
- pinnedWriteNAligned :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> Fold m a (Array a)
- write :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a)
- pinnedWrite :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a)
- unsafeMakePure :: Monad m => Fold IO a b -> Fold m a b
- chunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a)
- pinnedChunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a)
- bufferChunks :: (MonadIO m, Unbox a) => Stream m a -> m (StreamK m (Array a))
- flattenArrays :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a
- flattenArraysRev :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a
- unsafeIndex :: forall a. Unbox a => Int -> Array a -> a
- fromStreamN :: (MonadIO m, Unbox a) => Int -> Stream m a -> m (Array a)
- fromStream :: (MonadIO m, Unbox a) => Stream m a -> m (Array a)
- writeLastN :: (Storable a, Unbox a, MonadIO m) => Int -> Fold m a (Array a)
- reader :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a
- readerUnsafe :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a
- producer :: forall m a. (Monad m, Unbox a) => Producer m (Array a) a
- getIndex :: forall a. Unbox a => Int -> Array a -> Maybe a
- getIndexRev :: forall a. Unbox a => Int -> Array a -> Maybe a
- last :: Unbox a => Array a -> Maybe a
- getIndices :: (Monad m, Unbox a) => Stream m Int -> Unfold m (Array a) a
- getIndicesFromThenTo :: Unfold m (Int, Int, Int, Array a) a
- null :: Array a -> Bool
- binarySearch :: a -> Array a -> Maybe Int
- findIndicesOf :: (a -> Bool) -> Unfold Identity (Array a) Int
- cast :: forall a b. Unbox b => Array a -> Maybe (Array b)
- asBytes :: Array a -> Array Word8
- castUnsafe :: Array a -> Array b
- asCStringUnsafe :: Array a -> (CString -> IO b) -> IO b
- getSliceUnsafe :: forall a. Unbox a => Int -> Int -> Array a -> Array a
- genSlicesFromLen :: forall m a. (Monad m, Unbox a) => Int -> Int -> Unfold m (Array a) (Int, Int)
- getSlicesFromLen :: forall m a. (Monad m, Unbox a) => Int -> Int -> Unfold m (Array a) (Array a)
- splitOn :: (Monad m, Unbox a) => (a -> Bool) -> Array a -> Stream m (Array a)
- streamTransform :: forall m a b. (MonadIO m, Unbox a, Unbox b) => (Stream m a -> Stream m b) -> Array a -> m (Array b)
- streamFold :: (Monad m, Unbox a) => (Stream m a -> m b) -> Array a -> m b
- fold :: forall m a b. (Monad m, Unbox a) => Fold m a b -> Array a -> m b
- encodeAs :: forall a. Serialize a => PinnedState -> a -> Array Word8
- serialize :: Serialize a => a -> Array Word8
- pinnedSerialize :: Serialize a => a -> Array Word8
- deserialize :: Serialize a => Array Word8 -> a
Setup
>>>
:m
>>>
:set -XFlexibleContexts
>>>
:set -XMagicHash
>>>
import Data.Function ((&))
>>>
import Data.Functor.Identity (Identity(..))
>>>
import System.IO.Unsafe (unsafePerformIO)
>>>
import Streamly.Data.Array (Array)
>>>
import Streamly.Data.Stream (Stream)
>>>
import qualified Streamly.Data.Array as Array
>>>
import qualified Streamly.Data.Fold as Fold
>>>
import qualified Streamly.Data.Stream as Stream
For APIs that have not been released yet.
>>>
import qualified Streamly.Internal.Data.Array as Array
Design Notes
To summarize:
- Arrays are finite and fixed in size
- provide O(1) access to elements
- store only data and not functions
- provide efficient IO interfacing
Foldable
instance is not provided because the implementation would be much
less efficient compared to folding via streams. Semigroup
and Monoid
instances should be used with care; concatenating arrays using binary
operations can be highly inefficient. Instead, use
toArray
to concatenate N
arrays at once.
Each array is one pointer visible to the GC. Too many small arrays (e.g. single byte) are only as good as holding those elements in a Haskell list. However, small arrays can be compacted into large ones to reduce the overhead. To hold 32GB memory in 32k sized buffers we need 1 million arrays if we use one array for each chunk. This is still significant to add pressure to GC.
The Array Type
Type
We can use an Unbox
constraint in the Array type and the constraint can
be automatically provided to a function that pattern matches on the Array
type. However, it has huge performance cost, so we do not use it.
Investigate a GHC improvement possiblity.
Array | |
|
Instances
a ~ Char => IsString (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type fromString :: String -> Array a # | |
Unbox a => Monoid (Array a) Source # | |
Unbox a => Semigroup (Array a) Source # | |
Unbox a => IsList (Array a) Source # | |
(Unbox a, Read a, Show a) => Read (Array a) Source # | |
(Show a, Unbox a) => Show (Array a) Source # | |
(Unbox a, Eq a) => Eq (Array a) Source # | |
(Unbox a, Ord a) => Ord (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type | |
Serialize (Array a) Source # | |
Defined in Streamly.Internal.Data.Serialize.Type | |
type Item (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type |
asPtrUnsafe :: MonadIO m => Array a -> (Ptr a -> m b) -> m b Source #
Use an Array a
as Ptr a
.
See asPtrUnsafe
in the Mutable array module for more details.
Unsafe
Pre-release
Freezing and Thawing
unsafeFreeze :: MutArray a -> Array a Source #
Makes an immutable array using the underlying memory of the mutable array.
Please make sure that there are no other references to the mutable array lying around, so that it is never used after freezing it using unsafeFreeze. If the underlying array is mutated, the immutable promise is lost.
Pre-release
unsafeFreezeWithShrink :: Unbox a => MutArray a -> Array a Source #
Similar to unsafeFreeze
but uses rightSize
on the mutable array
first.
unsafeThaw :: Array a -> MutArray a Source #
Makes a mutable array using the underlying memory of the immutable array.
Please make sure that there are no other references to the immutable array lying around, so that it is never used after thawing it using unsafeThaw. If the resulting array is mutated, any references to the older immutable array are mutated as well.
Pre-release
Pinning and Unpinning
pin :: Array a -> IO (Array a) Source #
Return a copy of the Array
in pinned memory if unpinned, else return the
original array.
unpin :: Array a -> IO (Array a) Source #
Return a copy of the Array
in unpinned memory if pinned, else return the
original array.
Construction
fromList :: Unbox a => [a] -> Array a Source #
Create an Array
from a list. The list must be of finite size.
fromListN :: Unbox a => Int -> [a] -> Array a Source #
Create an Array
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.
pinnedFromListN :: Unbox a => Int -> [a] -> Array a Source #
Like fromListN
but creates a pinned array.
fromListRev :: Unbox a => [a] -> Array a Source #
Create an Array
from a list in reverse order. The list must be of finite
size.
Pre-release
fromListRevN :: Unbox a => Int -> [a] -> Array a Source #
Create an Array
from the first N elements of a list in reverse order.
The array is allocated to size N, if the list terminates before N elements
then the array may hold less than N elements.
Pre-release
fromPureStream :: Unbox a => Stream Identity a -> Array a Source #
Convert a pure stream in Identity monad to an immutable array.
Same as the following but with better performance:
>>>
fromPureStream = Array.fromList . runIdentity . Stream.toList
fromByteStr# :: Addr# -> Array Word8 Source #
Copy a null terminated immutable Addr#
Word8 sequence into an array.
Unsafe: The caller is responsible for safe addressing.
Note that this is completely safe when reading from Haskell string literals because they are guaranteed to be NULL terminated:
>>>
Array.toList $ Array.fromByteStr# "\1\2\3\0"#
[1,2,3]
Split
Cloning arrays
Elimination
unsafeIndexIO :: forall a. Unbox a => Int -> Array a -> IO a Source #
Return element at the specified index without checking the bounds.
Unsafe because it does not check the bounds of the array.
getIndexUnsafe :: forall a. Unbox a => Int -> Array a -> a Source #
Return element at the specified index without checking the bounds.
byteLength :: Array a -> Int Source #
O(1) Get the byte length of the array.
length :: Unbox a => Array a -> Int Source #
O(1) Get the length of the array i.e. the number of elements in the array.
splitAt :: Unbox a => Int -> Array a -> (Array a, Array a) Source #
Create two slices of an array without copying the original array. The
specified index i
is the first index of the second slice.
read :: (Monad m, Unbox a) => Array a -> Stream m a Source #
Convert an Array
into a stream.
Pre-release
readRev :: (Monad m, Unbox a) => Array a -> Stream m a Source #
Convert an Array
into a stream in reverse order.
Pre-release
readerRev :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a Source #
Unfold an array into a stream in reverse order.
Folds
writeN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
writeN n
folds a maximum of n
elements from the input stream to an
Array
.
pinnedWriteN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
Like fromListN
but creates a pinned array.
writeNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
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.
data ArrayUnsafe a Source #
pinnedWriteNAligned :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> Fold m a (Array a) Source #
pinnedWriteNAligned alignment n
folds a maximum of n
elements from the input
stream to an Array
aligned to the given size.
Pre-release
write :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a) Source #
Fold the whole input to a single array.
Caution! Do not use this on infinite streams.
pinnedWrite :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a) Source #
Like write
but creates a pinned array.
unsafeMakePure :: Monad m => Fold IO a b -> Fold m a b Source #
Fold "step" has a dependency on "initial", and each step is dependent on the previous invocation of step due to state passing, finally extract depends on the result of step, therefore, as long as the fold is driven in the correct order the operations would be correctly ordered. We need to ensure that we strictly evaluate the previous step completely before the next step.
To not share the same array we need to make sure that the result of "initial" is not shared. Existential type ensures that it does not get shared across different folds. However, if we invoke "initial" multiple times for the same fold, there is a possiblity of sharing the two because the compiler would consider it as a pure value. One such example is the chunksOf combinator, or using an array creation fold with foldMany combinator. Is there a proper way in GHC to tell it to not share a pure expression in a particular case?
For this reason array creation folds have a MonadIO constraint. Pure folds could be unsafe and dangerous. This is dangerous especially when used with foldMany like operations.
>>>
unsafePureWrite = Array.unsafeMakePure Array.write
Streams of arrays
chunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a) Source #
chunksOf n stream
groups the elements in the input stream into arrays of
n
elements each.
Same as the following but may be more efficient:
>>>
chunksOf n = Stream.foldMany (Array.writeN n)
Pre-release
pinnedChunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a) Source #
Like chunksOf
but creates pinned arrays.
flattenArrays :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a Source #
Use the "read" unfold instead.
flattenArrays = unfoldMany read
We can try this if there are any fusion issues in the unfold.
flattenArraysRev :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a Source #
Use the "readRev" unfold instead.
flattenArrays = unfoldMany readRev
We can try this if there are any fusion issues in the unfold.
Deprecated
unsafeIndex :: forall a. Unbox a => Int -> Array a -> a Source #
Deprecated: Please use getIndexUnsafe
instead
Type
We can use an Unbox
constraint in the Array type and the constraint can
be automatically provided to a function that pattern matches on the Array
type. However, it has huge performance cost, so we do not use it.
Investigate a GHC improvement possiblity.
Array | |
|
Instances
a ~ Char => IsString (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type fromString :: String -> Array a # | |
Unbox a => Monoid (Array a) Source # | |
Unbox a => Semigroup (Array a) Source # | |
Unbox a => IsList (Array a) Source # | |
(Unbox a, Read a, Show a) => Read (Array a) Source # | |
(Show a, Unbox a) => Show (Array a) Source # | |
(Unbox a, Eq a) => Eq (Array a) Source # | |
(Unbox a, Ord a) => Ord (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type | |
Serialize (Array a) Source # | |
Defined in Streamly.Internal.Data.Serialize.Type | |
type Item (Array a) Source # | |
Defined in Streamly.Internal.Data.Array.Type |
asPtrUnsafe :: MonadIO m => Array a -> (Ptr a -> m b) -> m b Source #
Use an Array a
as Ptr a
.
See asPtrUnsafe
in the Mutable array module for more details.
Unsafe
Pre-release
Freezing and Thawing
unsafeFreeze :: MutArray a -> Array a Source #
Makes an immutable array using the underlying memory of the mutable array.
Please make sure that there are no other references to the mutable array lying around, so that it is never used after freezing it using unsafeFreeze. If the underlying array is mutated, the immutable promise is lost.
Pre-release
unsafeFreezeWithShrink :: Unbox a => MutArray a -> Array a Source #
Similar to unsafeFreeze
but uses rightSize
on the mutable array
first.
unsafeThaw :: Array a -> MutArray a Source #
Makes a mutable array using the underlying memory of the immutable array.
Please make sure that there are no other references to the immutable array lying around, so that it is never used after thawing it using unsafeThaw. If the resulting array is mutated, any references to the older immutable array are mutated as well.
Pre-release
Pinning and Unpinning
pin :: Array a -> IO (Array a) Source #
Return a copy of the Array
in pinned memory if unpinned, else return the
original array.
unpin :: Array a -> IO (Array a) Source #
Return a copy of the Array
in unpinned memory if pinned, else return the
original array.
Construction
fromList :: Unbox a => [a] -> Array a Source #
Create an Array
from a list. The list must be of finite size.
fromListN :: Unbox a => Int -> [a] -> Array a Source #
Create an Array
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.
pinnedFromListN :: Unbox a => Int -> [a] -> Array a Source #
Like fromListN
but creates a pinned array.
fromListRev :: Unbox a => [a] -> Array a Source #
Create an Array
from a list in reverse order. The list must be of finite
size.
Pre-release
fromListRevN :: Unbox a => Int -> [a] -> Array a Source #
Create an Array
from the first N elements of a list in reverse order.
The array is allocated to size N, if the list terminates before N elements
then the array may hold less than N elements.
Pre-release
fromPureStream :: Unbox a => Stream Identity a -> Array a Source #
Convert a pure stream in Identity monad to an immutable array.
Same as the following but with better performance:
>>>
fromPureStream = Array.fromList . runIdentity . Stream.toList
fromByteStr# :: Addr# -> Array Word8 Source #
Copy a null terminated immutable Addr#
Word8 sequence into an array.
Unsafe: The caller is responsible for safe addressing.
Note that this is completely safe when reading from Haskell string literals because they are guaranteed to be NULL terminated:
>>>
Array.toList $ Array.fromByteStr# "\1\2\3\0"#
[1,2,3]
Split
Cloning arrays
Elimination
unsafeIndexIO :: forall a. Unbox a => Int -> Array a -> IO a Source #
Return element at the specified index without checking the bounds.
Unsafe because it does not check the bounds of the array.
getIndexUnsafe :: forall a. Unbox a => Int -> Array a -> a Source #
Return element at the specified index without checking the bounds.
byteLength :: Array a -> Int Source #
O(1) Get the byte length of the array.
length :: Unbox a => Array a -> Int Source #
O(1) Get the length of the array i.e. the number of elements in the array.
splitAt :: Unbox a => Int -> Array a -> (Array a, Array a) Source #
Create two slices of an array without copying the original array. The
specified index i
is the first index of the second slice.
read :: (Monad m, Unbox a) => Array a -> Stream m a Source #
Convert an Array
into a stream.
Pre-release
readRev :: (Monad m, Unbox a) => Array a -> Stream m a Source #
Convert an Array
into a stream in reverse order.
Pre-release
readerRev :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a Source #
Unfold an array into a stream in reverse order.
Folds
writeN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
writeN n
folds a maximum of n
elements from the input stream to an
Array
.
pinnedWriteN :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
Like fromListN
but creates a pinned array.
writeNUnsafe :: forall m a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a) Source #
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.
data ArrayUnsafe a Source #
pinnedWriteNAligned :: forall m a. (MonadIO m, Unbox a) => Int -> Int -> Fold m a (Array a) Source #
pinnedWriteNAligned alignment n
folds a maximum of n
elements from the input
stream to an Array
aligned to the given size.
Pre-release
write :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a) Source #
Fold the whole input to a single array.
Caution! Do not use this on infinite streams.
pinnedWrite :: forall m a. (MonadIO m, Unbox a) => Fold m a (Array a) Source #
Like write
but creates a pinned array.
unsafeMakePure :: Monad m => Fold IO a b -> Fold m a b Source #
Fold "step" has a dependency on "initial", and each step is dependent on the previous invocation of step due to state passing, finally extract depends on the result of step, therefore, as long as the fold is driven in the correct order the operations would be correctly ordered. We need to ensure that we strictly evaluate the previous step completely before the next step.
To not share the same array we need to make sure that the result of "initial" is not shared. Existential type ensures that it does not get shared across different folds. However, if we invoke "initial" multiple times for the same fold, there is a possiblity of sharing the two because the compiler would consider it as a pure value. One such example is the chunksOf combinator, or using an array creation fold with foldMany combinator. Is there a proper way in GHC to tell it to not share a pure expression in a particular case?
For this reason array creation folds have a MonadIO constraint. Pure folds could be unsafe and dangerous. This is dangerous especially when used with foldMany like operations.
>>>
unsafePureWrite = Array.unsafeMakePure Array.write
Streams of arrays
chunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a) Source #
chunksOf n stream
groups the elements in the input stream into arrays of
n
elements each.
Same as the following but may be more efficient:
>>>
chunksOf n = Stream.foldMany (Array.writeN n)
Pre-release
pinnedChunksOf :: forall m a. (MonadIO m, Unbox a) => Int -> Stream m a -> Stream m (Array a) Source #
Like chunksOf
but creates pinned arrays.
flattenArrays :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a Source #
Use the "read" unfold instead.
flattenArrays = unfoldMany read
We can try this if there are any fusion issues in the unfold.
flattenArraysRev :: forall m a. (MonadIO m, Unbox a) => Stream m (Array a) -> Stream m a Source #
Use the "readRev" unfold instead.
flattenArrays = unfoldMany readRev
We can try this if there are any fusion issues in the unfold.
Deprecated
unsafeIndex :: forall a. Unbox a => Int -> Array a -> a Source #
Deprecated: Please use getIndexUnsafe
instead
Construction
fromStreamN :: (MonadIO m, Unbox a) => Int -> Stream m a -> m (Array a) Source #
Create an Array
from the first N elements of a stream. The array is
allocated to size N, if the stream terminates before N elements then the
array may hold less than N elements.
Pre-release
fromStream :: (MonadIO m, Unbox a) => Stream m a -> m (Array a) Source #
Create an Array
from a stream. This is useful when we want to create a
single array from a stream of unknown size. writeN
is at least twice
as efficient when the size is already known.
Note that if the input stream is too large memory allocation for the array
may fail. When the stream size is not known, chunksOf
followed by
processing of indvidual arrays in the resulting stream should be preferred.
Pre-release
writeLastN :: (Storable a, Unbox a, MonadIO m) => Int -> Fold m a (Array a) Source #
writeLastN n
folds a maximum of n
elements from the end of the input
stream to an Array
.
Unfolds
reader :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a Source #
Unfold an array into a stream.
readerUnsafe :: forall m a. (Monad m, Unbox a) => Unfold m (Array a) a Source #
Unfold an array into a stream, does not check the end of the array, the user is responsible for terminating the stream within the array bounds. For high performance application where the end condition can be determined by a terminating fold.
Written in the hope that it may be faster than "read", however, in the case for which this was written, "read" proves to be faster even though the core generated with unsafeRead looks simpler.
Pre-release
Random Access
getIndex :: forall a. Unbox a => Int -> Array a -> Maybe a Source #
O(1) Lookup the element at the given index. Index starts from 0.
getIndexRev :: forall a. Unbox a => Int -> Array a -> Maybe a Source #
Like getIndex
but indexes the array in reverse from the end.
Pre-release
getIndices :: (Monad m, Unbox a) => Stream m Int -> Unfold m (Array a) a Source #
Given a stream of array indices, read the elements on those indices from the supplied Array. An exception is thrown if an index is out of bounds.
This is the most general operation. We can implement other operations in terms of this:
read = let u = lmap (arr -> (0, length arr - 1)) Unfold.enumerateFromTo in Unfold.lmap f (getIndices arr) readRev = let i = length arr - 1 in Unfold.lmap f (getIndicesFromThenTo i (i - 1) 0)
Pre-release
getIndicesFromThenTo :: Unfold m (Int, Int, Int, Array a) a Source #
Unfolds (from, then, to, array)
generating a finite stream whose first
element is the array value from the index from
and the successive elements
are from the indices in increments of then
up to to
. Index enumeration
can occur downwards or upwards depending on whether then
comes before or
after from
.
getIndicesFromThenTo = let f (from, next, to, arr) = (Stream.enumerateFromThenTo from next to, arr) in Unfold.lmap f getIndices
Unimplemented
Size
Search
binarySearch :: a -> Array a -> Maybe Int Source #
Given a sorted array, perform a binary search to find the given element. Returns the index of the element if found.
Unimplemented
findIndicesOf :: (a -> Bool) -> Unfold Identity (Array a) Int Source #
Perform a linear search to find all the indices where a given element is present in an array.
Unimplemented
Casting
cast :: forall a b. Unbox b => Array a -> Maybe (Array b) Source #
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 :: Array a -> Array b Source #
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
asCStringUnsafe :: Array a -> (CString -> IO b) -> IO b Source #
Convert an array of any type into a null terminated CString Ptr. If the array is unpinned it is first converted to a pinned array which requires a copy.
Unsafe
O(n) Time: (creates a copy of the array)
Pre-release
Subarrays
O(1) Slice an array in constant time.
Caution: The bounds of the slice are not checked.
Unsafe
Pre-release
:: forall m a. (Monad m, Unbox a) | |
=> Int | from index |
-> Int | length of the slice |
-> Unfold m (Array a) (Array a) |
Generate a stream of slices of specified length from an array, starting from the supplied array index. The last slice may be shorter than the requested length.
Pre-release/
splitOn :: (Monad m, Unbox a) => (a -> Bool) -> Array a -> Stream m (Array a) Source #
Split the array into a stream of slices using a predicate. The element matching the predicate is dropped.
Pre-release
Streaming Operations
streamTransform :: forall m a b. (MonadIO m, Unbox a, Unbox b) => (Stream m a -> Stream m b) -> Array a -> m (Array b) Source #
Transform an array into another array using a stream transformation operation.
Pre-release
Folding
streamFold :: (Monad m, Unbox a) => (Stream m a -> m b) -> Array a -> m b Source #
Fold an array using a stream fold operation.
Pre-release
fold :: forall m a b. (Monad m, Unbox a) => Fold m a b -> Array a -> m b Source #
Fold an array using a Fold
.
Pre-release