| Copyright | (c) 2019 Composewell Technologies |
|---|---|
| License | BSD3 |
| Maintainer | streamly@composewell.com |
| Stability | released |
| Portability | GHC |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Streamly.Data.Array.Foreign
Description
Deprecated: Please use Streamly.Data.Array module from the streamly-core package.
This module provides immutable arrays in pinned memory (non GC memory) suitable for long lived data storage, random access and for interfacing with the operating system.
Arrays in this module are chunks of pinned memory that hold a sequence of
Storable values of a given type, they cannot store non-serializable data
like functions. Once created an array cannot be modified. Pinned memory
allows efficient buffering of long lived data without adding any impact to
GC. One array is just one pointer visible to GC and it does not have to be
copied across generations. Moreover, pinned memory allows communication
with foreign consumers and producers (e.g. file or network IO) without
copying the data.
Programmer Notes
Array creation APIs require a MonadIO Monad, except fromList which is a
pure API. To operate on streams in pure Monads like Identity you can hoist
it to IO monad as follows:
>>>import Data.Functor.Identity (Identity, runIdentity)>>>s = Stream.fromList [1..10] :: SerialT Identity Int>>>s1 = Stream.hoist (return . runIdentity) s :: SerialT IO Int>>>Stream.fold Array.write s1 :: IO (Array Int)fromList [1,2,3,4,5,6,7,8,9,10]
unsafePerformIO can be used to get a pure API from IO, as long as you know
it is safe to do so:
>>>import System.IO.Unsafe (unsafePerformIO)>>>unsafePerformIO $ Stream.fold Array.write s1 :: Array IntfromList [1,2,3,4,5,6,7,8,9,10]
To apply a transformation to an array use read to unfold the array into a
stream, apply a transformation on the stream and then use write to fold it
back to an array.
This module is designed to be imported qualified:
import qualified Streamly.Data.Array as Array
For experimental APIs see Streamly.Internal.Data.Array.
Synopsis
- data Array a
- fromListN :: Unbox a => Int -> [a] -> Array a
- fromList :: Unbox a => [a] -> Array a
- writeN :: forall (m :: Type -> Type) a. (MonadIO m, Unbox a) => Int -> Fold m a (Array a)
- write :: forall (m :: Type -> Type) a. (MonadIO m, Unbox a) => Fold m a (Array a)
- writeLastN :: forall a (m :: Type -> Type). (Storable a, Unbox a, MonadIO m) => Int -> Fold m a (Array a)
- toList :: Unbox a => Array a -> [a]
- read :: forall (m :: Type -> Type) a. (Monad m, Unbox a) => Array a -> Stream m a
- readRev :: forall (m :: Type -> Type) a. (Monad m, Unbox a) => Array a -> Stream m a
- cast :: forall a b. Unbox b => Array a -> Maybe (Array b)
- asBytes :: Array a -> Array Word8
- length :: Unbox a => Array a -> Int
- getIndex :: Unbox a => Int -> Array a -> Maybe a
Documentation
Instances
| NFData1 Array Source # | |
Defined in Streamly.Data.Array.Foreign | |
| a ~ Char => IsString (Array a) | |
Defined in Streamly.Internal.Data.Array.Type Methods fromString :: String -> Array a Source # | |
| Unbox a => Monoid (Array a) | |
| Unbox a => Semigroup (Array a) | |
| Unbox a => IsList (Array a) | |
| (Unbox a, Read a, Show a) => Read (Array a) | |
| (Show a, Unbox a) => Show (Array a) | |
| NFData (Array a) Source # | |
Defined in Streamly.Data.Array.Foreign | |
| Eq (Array Int16) | |
| Eq (Array Int32) | |
| Eq (Array Int64) | |
| Eq (Array Int8) | |
| Eq (Array Word16) | |
| Eq (Array Word32) | |
| Eq (Array Word64) | |
| Eq (Array Word8) | |
| Eq (Array Char) | |
| Eq (Array Int) | |
| (Unbox a, Eq a) => Eq (Array a) | |
| (Unbox a, Ord a) => Ord (Array a) | |
Defined in Streamly.Internal.Data.Array.Type | |
| type Item (Array a) | |
Defined in Streamly.Internal.Data.Array.Type | |
Arrays
Construction
When performance matters, the fastest way to generate an array is
writeN. IsList and IsString instances can be
used to conveniently construct arrays from literal values.
OverloadedLists extension or fromList can be used to construct an
array from a list literal. Similarly, OverloadedStrings extension or
fromList can be used to construct an array from a string literal.
writeLastN :: forall a (m :: Type -> Type). (Storable a, Unbox a, MonadIO m) => Int -> Fold m a (Array a) #