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{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE CPP #-}
module Data.Primitive.ByteArray.Util where
import GHC.Exts (Ptr(..))
import GHC.TypeLits
import Control.Monad.Primitive
import qualified Data.ByteString as B
import qualified Data.ByteString.Unsafe as B
import Data.Primitive.Addr
import Data.Primitive.Types
import Data.Primitive.ByteArray
import Data.Word
import Foreign.Ptr
newtype Offset (n :: Nat) = Offset Int
offset :: KnownNat n => Offset n
offset = let k = Offset $ fromIntegral $ natVal k in k
(+.) :: Offset j -> Offset k -> Offset (j + k)
Offset j +. Offset k = Offset (j + k)
type family SizeOf a :: Nat
class IsMultipleOf (n::Nat) (k::Nat)
instance n ~ (q * k) => IsMultipleOf n k
writeAtByte :: ( Prim a
, PrimMonad m
#if __GLASGOW_HASKELL__ >= 802
, IsMultipleOf n (SizeOf a)
#endif
) => MutableByteArray (PrimState m) -> Offset n -> a -> m ()
writeAtByte buf (Offset offset) a = writeByteArray buf (div offset $ (sizeOf a)) a
{-# INLINE writeAtByte #-}
readAtByte :: forall a m n.
( Prim a
, PrimMonad m
#if __GLASGOW_HASKELL__ >= 802
, IsMultipleOf n (SizeOf a)
#endif
) => MutableByteArray (PrimState m) -> Offset n -> m a
readAtByte buf (Offset offset) = readByteArray buf (div offset $ (sizeOf (undefined :: a)))
{-# INLINE readAtByte #-}
writeStringAt :: PrimMonad m => MutableByteArray s -> Int -> B.ByteString -> m (Ptr a)
writeStringAt src o bsname = do
(p,cnt) <- unsafeIOToPrim $ B.unsafeUseAsCStringLen bsname return
let nptr = ptr (mutableByteArrayContents src) `plusPtr` o
copyAddr (adr nptr) (adr p) cnt
writeOffAddr (adr nptr) cnt (0 :: Word8)
return nptr
ptr :: Addr -> Ptr a
ptr (Addr a) = Ptr a
adr :: Ptr a -> Addr
adr (Ptr a) = Addr a
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