{-# LANGUAGE ScopedTypeVariables #-} -- | -- Copyright : (c) 2010 Simon Meier -- -- License : BSD3-style (see LICENSE) -- -- Maintainer : Simon Meier <iridcode@gmail.com> -- Stability : experimental -- Portability : GHC -- -- Conversion of 'Float's and 'Double's to 'Word32's and 'Word64's. -- module Data.ByteString.Builder.Prim.Internal.Floating ( -- coerceFloatToWord32 -- , coerceDoubleToWord64 encodeFloatViaWord32F , encodeDoubleViaWord64F ) where import Foreign import Data.ByteString.Builder.Prim.Internal {- We work around ticket http://hackage.haskell.org/trac/ghc/ticket/4092 using the FFI to store the Float/Double in the buffer and peek it out again from there. -} -- | Encode a 'Float' using a 'Word32' encoding. -- -- PRE: The 'Word32' encoding must have a size of at least 4 bytes. {-# INLINE encodeFloatViaWord32F #-} encodeFloatViaWord32F :: FixedPrim Word32 -> FixedPrim Float encodeFloatViaWord32F w32fe | size w32fe < sizeOf (undefined :: Float) = error $ "encodeFloatViaWord32F: encoding not wide enough" | otherwise = fixedPrim (size w32fe) $ \x op -> do poke (castPtr op) x x' <- peek (castPtr op) runF w32fe x' op -- | Encode a 'Double' using a 'Word64' encoding. -- -- PRE: The 'Word64' encoding must have a size of at least 8 bytes. {-# INLINE encodeDoubleViaWord64F #-} encodeDoubleViaWord64F :: FixedPrim Word64 -> FixedPrim Double encodeDoubleViaWord64F w64fe | size w64fe < sizeOf (undefined :: Float) = error $ "encodeDoubleViaWord64F: encoding not wide enough" | otherwise = fixedPrim (size w64fe) $ \x op -> do poke (castPtr op) x x' <- peek (castPtr op) runF w64fe x' op