84 lines
2.3 KiB
Haskell
84 lines
2.3 KiB
Haskell
{-# LANGUAGE FlexibleContexts #-}
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{-# LANGUAGE CPP #-}
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{-# LANGUAGE ScopedTypeVariables #-}
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#ifndef MIN_VERSION_base
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#define MIN_VERSION_base(x,y,z) 1
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#endif
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-- | IEEE-754 parsing, as described in this stack-overflow article:
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--
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-- <http://stackoverflow.com/questions/6976684/converting-ieee-754-floating-point-in-haskell-word32-64-to-and-from-haskell-float/7002812#7002812>
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module Data.Serialize.IEEE754 (
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-- * IEEE-754 reads
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getFloat32le
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, getFloat32be
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, getFloat64le
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, getFloat64be
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-- * IEEE-754 writes
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, putFloat32le
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, putFloat32be
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, putFloat64le
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, putFloat64be
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) where
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import Data.Word ( Word32, Word64 )
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import Data.Serialize.Get
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import Data.Serialize.Put
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import qualified Data.ByteString.Builder as Builder
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import System.IO.Unsafe (unsafeDupablePerformIO)
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import Foreign.Marshal.Alloc (alloca)
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import Foreign.Storable (peek, poke)
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import Foreign.Ptr (castPtr, Ptr)
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#if !(MIN_VERSION_base(4,8,0))
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import Control.Applicative ( (<$>) )
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#endif
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-- | Read a Float in little endian IEEE-754 format
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getFloat32le :: Get Float
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getFloat32le = wordToFloat <$> getWord32le
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-- | Read a Float in big endian IEEE-754 format
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getFloat32be :: Get Float
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getFloat32be = wordToFloat <$> getWord32be
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-- | Read a Double in little endian IEEE-754 format
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getFloat64le :: Get Double
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getFloat64le = wordToDouble <$> getWord64le
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-- | Read a Double in big endian IEEE-754 format
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getFloat64be :: Get Double
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getFloat64be = wordToDouble <$> getWord64be
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-- | Write a Float in little endian IEEE-754 format
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putFloat32le :: Float -> Put
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putFloat32le = putBuilder . Builder.floatLE
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-- | Write a Float in big endian IEEE-754 format
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putFloat32be :: Float -> Put
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putFloat32be = putBuilder . Builder.floatBE
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-- | Write a Double in little endian IEEE-754 format
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putFloat64le :: Double -> Put
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putFloat64le = putBuilder . Builder.doubleLE
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-- | Write a Double in big endian IEEE-754 format
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putFloat64be :: Double -> Put
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putFloat64be = putBuilder . Builder.doubleBE
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{-# INLINE wordToFloat #-}
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wordToFloat :: Word32 -> Float
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wordToFloat w = unsafeDupablePerformIO $ alloca $ \(ptr :: Ptr Word32) -> do
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poke ptr w
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peek (castPtr ptr)
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{-# INLINE wordToDouble #-}
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wordToDouble :: Word64 -> Double
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wordToDouble w = unsafeDupablePerformIO $ alloca $ \(ptr :: Ptr Word64) -> do
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poke ptr w
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peek (castPtr ptr)
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