Typed.purs

module Data.ArrayBuffer.Typed( asInt8Array
                             , asInt16Array
                             , asInt32Array
                             , asUint8Array
                             , asUint16Array
                             , asUint32Array
                             , asUint8ClampedArray
                             , asFloat32Array
                             , asFloat64Array
                             , dataView
                             , set
                             , unsafeAt
                             , hasIndex
                             , at
                             , toArray
                             , toIntArray
                             ) where

import Prelude
import Effect (Effect)
import Data.ArrayBuffer.Types (ArrayView, ByteOffset, DataView, Float64Array, Float32Array, Uint8ClampedArray, Uint32Array, Uint16Array, Uint8Array, Int32Array, Int16Array, Int8Array)
import Data.Function.Uncurried (Fn2, Fn3, runFn2, runFn3)
import Data.Maybe (Maybe(..))

-- | Create typed int8 array viewing the buffer mapped by the `DataView`
foreign import asInt8Array :: DataView -> Int8Array

-- | Create typed int16 array viewing the buffer mapped by the `DataView`
foreign import asInt16Array :: DataView -> Int16Array

-- | Create typed int32 array viewing the buffer mapped by the `DataView`
foreign import asInt32Array :: DataView -> Int32Array

-- | Create typed uint8 array viewing the buffer mapped by the `DataView`
foreign import asUint8Array :: DataView -> Uint8Array

-- | Create typed uint16 array viewing the buffer mapped by the `DataView`
foreign import asUint16Array :: DataView -> Uint16Array

-- | Create typed uint32 array viewing the buffer mapped by the `DataView`
foreign import asUint32Array :: DataView -> Uint32Array

-- | Create typed uint8 clamped array viewing the buffer mapped by the `DataView`
foreign import asUint8ClampedArray :: DataView -> Uint8ClampedArray

-- | Create typed float32 array viewing the buffer mapped by the `DataView`
foreign import asFloat32Array :: DataView -> Float32Array

-- | Create typed float64 array viewing the buffer mapped by the `DataView`
foreign import asFloat64Array :: DataView -> Float64Array

-- | Interpret typed array as a `DataView`.
foreign import dataView :: forall a. ArrayView a -> DataView

foreign import setImpl :: forall a. Fn3 (ArrayView a) ByteOffset (ArrayView a) (Effect Unit)

-- | Stores multiple values in the last typed array, reading input values from ther first typed array.
set :: forall a. ArrayView a -> ByteOffset -> ArrayView a -> Effect Unit
set = runFn3 setImpl

foreign import unsafeAtImpl :: forall a. Fn2 (ArrayView a) Int (Effect Number)

-- | Fetch element at index.
unsafeAt :: forall a. ArrayView a -> Int -> Effect Number
unsafeAt = runFn2 unsafeAtImpl

foreign import hasIndexImpl :: forall a. Fn2 (ArrayView a) Int Boolean

-- | Determine if a certain index is valid.
hasIndex :: forall a. ArrayView a -> Int -> Boolean
hasIndex = runFn2 hasIndexImpl

-- | Fetch element at index.
at :: forall a. ArrayView a -> Int -> Effect (Maybe Number)
at a n = do
  if a `hasIndex` n
    then do
      element <- unsafeAt a n
      pure $ Just element
    else
      pure Nothing

-- | Turn typed array into an array.
foreign import toArray :: forall a. ArrayView a -> Array Number

-- | Turn typed array into integer array.
foreign import toIntArray :: forall a. ArrayView a -> Array Int