From: Ramakrishnan Muthukrishnan Date: Tue, 29 Dec 2015 08:29:49 +0000 (+0530) Subject: Lib: more refactoring of genInstructions X-Git-Url: https://git.rkrishnan.org/pf/content/frontends/install-details.html?a=commitdiff_plain;h=7f80f5c867a865f8b5369e0c8cc8926eac9e4447;p=hs-rsync.git Lib: more refactoring of genInstructions --- diff --git a/src/Lib.hs b/src/Lib.hs index 2443f7d..260de94 100644 --- a/src/Lib.hs +++ b/src/Lib.hs @@ -8,7 +8,7 @@ module Lib import Control.Monad.State import qualified Data.ByteString.Char8 as BS import qualified Data.ByteString.Lazy as BL -import Data.Digest.Adler32 (adler32) +import Data.Digest.Adler32 (adler32, adler32Update) import qualified Data.Map as M import Data.Word (Word8, Word32) import qualified Crypto.Hash.MD4 as MD4 @@ -41,24 +41,26 @@ data Instruction = RChar Word8 genInstructions :: [Signature] -> Integer -> BL.ByteString -> [Instruction] genInstructions f0sigs blockSize fnew = - evalState (go fnew) 0 + evalState (go fnew) sig0 where - go :: BL.ByteString -> State Word32 [Instruction] + sig0 = weakSig $ BL.take (fromIntegral blockSize) fnew + go :: BL.ByteString -> State Adler32checksum [Instruction] go fnew | fnew == BL.empty = return [] - | otherwise = + | otherwise = do let (blk, blks) = BL.splitAt (fromIntegral blockSize) fnew - adlerSum = weakSig blk - matches = M.lookup adlerSum f0AdlerTable >> + adlerSum <- get + let matches = M.lookup adlerSum f0AdlerTable >> M.lookup (blockSig blk) f0MD4Table - in - case matches of - Just idxs -> do - is <- go blks - return $ RBlk (head idxs) : is - Nothing -> do - put adlerSum - is <- go (BL.tail (blk `mappend` blks)) - return $ RChar (BL.head blk) : is + case matches of + Just idxs -> do + modify (`adler32Update` blk) + is <- go blks + return $ RBlk (head idxs) : is + Nothing -> do + let c = BL.head blk + modify (`adler32Update` BL.singleton c) + is <- go (BL.tail (blk `mappend` blks)) + return $ RChar c : is f0AdlerTable = toAdlerMap f0sigs f0MD4Table = toMD4Map f0sigs