49 lines
1.4 KiB
Haskell
49 lines
1.4 KiB
Haskell
-- |
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-- Module : Crypto.Internal.Compat
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-- License : BSD-style
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-- Maintainer : Vincent Hanquez <vincent@snarc.org>
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-- Stability : stable
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-- Portability : Good
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--
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-- This module try to keep all the difference between versions of base
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-- or other needed packages, so that modules don't need to use CPP
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--
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{-# LANGUAGE CPP #-}
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module Crypto.Internal.Compat
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( unsafeDoIO
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, popCount
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, byteSwap64
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) where
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import System.IO.Unsafe
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import Data.Word
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import Data.Bits
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-- | perform io for hashes that do allocation and ffi.
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-- unsafeDupablePerformIO is used when possible as the
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-- computation is pure and the output is directly linked
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-- to the input. we also do not modify anything after it has
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-- been returned to the user.
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unsafeDoIO :: IO a -> a
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#if __GLASGOW_HASKELL__ > 704
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unsafeDoIO = unsafeDupablePerformIO
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#else
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unsafeDoIO = unsafePerformIO
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#endif
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#if !(MIN_VERSION_base(4,5,0))
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popCount :: Word64 -> Int
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popCount n = loop 0 n
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where loop c 0 = c
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loop c i = loop (c + if testBit c 0 then 1 else 0) (i `shiftR` 1)
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#endif
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#if !(MIN_VERSION_base(4,7,0))
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byteSwap64 :: Word64 -> Word64
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byteSwap64 w =
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(w `shiftR` 56) .|. (w `shiftL` 56)
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.|. ((w `shiftR` 40) .&. 0xff00) .|. ((w .&. 0xff00) `shiftL` 40)
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.|. ((w `shiftR` 24) .&. 0xff0000) .|. ((w .&. 0xff0000) `shiftL` 24)
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.|. ((w `shiftR` 8) .&. 0xff000000) .|. ((w .&. 0xff000000) `shiftL` 8)
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#endif
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