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{-# LANGUAGE TypeFamilies, TypeOperators #-}
-- |
-- Module : Data.Double.Conversion.ByteStringBuilder
-- Copyright : (c) 2011 MailRank, Inc.
--
-- License : BSD-style
-- Maintainer : bos@serpentine.com
-- Stability : experimental
-- Portability : GHC
--
-- Fast, efficient support for converting between double precision
-- floating point values and bytestring builder.
module Data.Double.Conversion.Internal.ByteStringBuilder
(convert
) where
import Control.Monad (when)
import Data.ByteString.Builder.Prim.Internal (BoundedPrim, boudedPrim)
import Data.Double.Conversion.Internal.FFI (ForeignFloating)
import Data.Word (Word8)
import Foreign.C.Types (CDouble, CFloat, CInt)
import Foreign.Ptr (Ptr, plusPtr)
convert :: (RealFloat a, RealFloat b , b ~ ForeignFloating a) => String -> CInt -> (b -> Ptr Word8 -> IO CInt) -> BoundedPrim a
{-# SPECIALIZE convert :: String -> CInt -> (CDouble -> Ptr Word8 -> IO CInt) -> BoundedPrim Double #-}
{-# SPECIALIZE convert :: String -> CInt -> (CFloat -> Ptr Word8 -> IO CInt) -> BoundedPrim Float #-}
{-# INLINABLE convert #-}
convert func len act = boudedPrim (fromIntegral len) $ \val ptr -> do
size <- act (realToFrac val) ptr
when (size == -1) .
fail $ "Data.Double.Conversion.ByteString." ++ func ++
": conversion failed (invalid precision requested)"
return (ptr `plusPtr` (fromIntegral size))
|
