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|
-- ----------------------------------------------------------------------------
--
-- (c) The University of Glasgow 2006
--
-- Fingerprints for recompilation checking and ABI versioning.
--
-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/RecompilationAvoidance
--
-- ----------------------------------------------------------------------------
module Fingerprint (
Fingerprint(..), fingerprint0,
readHexFingerprint,
fingerprintData
) where
#include "md5.h"
##include "HsVersions.h"
import Outputable
import Foreign
import Foreign.C
import Text.Printf
import Data.Word
import Numeric ( readHex )
-- Using 128-bit MD5 fingerprints for now.
data Fingerprint = Fingerprint {-# UNPACK #-} !Word64 {-# UNPACK #-} !Word64
deriving (Eq, Ord)
-- or ByteString?
fingerprint0 :: Fingerprint
fingerprint0 = Fingerprint 0 0
instance Outputable Fingerprint where
ppr (Fingerprint w1 w2) = text (printf "%016x%016x" i1 i2)
where i1 = fromIntegral w1 :: Integer
i2 = fromIntegral w2 :: Integer
-- printf in GHC 6.4.2 didn't have Word64 instances
-- useful for parsing the output of 'md5sum', should we want to do that.
readHexFingerprint :: String -> Fingerprint
readHexFingerprint s = Fingerprint w1 w2
where (s1,s2) = splitAt 16 s
[(w1,"")] = readHex s1
[(w2,"")] = readHex (take 16 s2)
peekFingerprint :: Ptr Word8 -> IO Fingerprint
peekFingerprint p = do
let peekW64 :: Ptr Word8 -> Int -> Word64 -> IO Word64
STRICT3(peekW64)
peekW64 _ 0 i = return i
peekW64 p n i = do
w8 <- peek p
peekW64 (p `plusPtr` 1) (n-1)
((i `shiftL` 8) .|. fromIntegral w8)
high <- peekW64 p 8 0
low <- peekW64 (p `plusPtr` 8) 8 0
return (Fingerprint high low)
fingerprintData :: Ptr Word8 -> Int -> IO Fingerprint
fingerprintData buf len = do
allocaBytes (#const sizeof(struct MD5Context)) $ \pctxt -> do
c_MD5Init pctxt
c_MD5Update pctxt buf (fromIntegral len)
allocaBytes 16 $ \pdigest -> do
c_MD5Final pdigest pctxt
peekFingerprint (castPtr pdigest)
data MD5Context
foreign import ccall unsafe "MD5Init"
c_MD5Init :: Ptr MD5Context -> IO ()
foreign import ccall unsafe "MD5Update"
c_MD5Update :: Ptr MD5Context -> Ptr Word8 -> CInt -> IO ()
foreign import ccall unsafe "MD5Final"
c_MD5Final :: Ptr Word8 -> Ptr MD5Context -> IO ()
|
