RE: Data.HashTable bug

On Fri, 19 Mar 2004, Simon Marlow wrote:

I did post a hash table version of this program a while back, that I claimed was a factor of 3 faster at the time. Unfortunately the attachment in the archive is in base64 and I can't read it, and I've lost the code :-( If you can decode the attachment, it's here:

http://www.haskell.org/pipermail/haskell-cafe/2001-July/002061.html

Does the code below look familiar? /Josef \begin{code} -- compile with: ghc -O -package lang -- run with: ./a.out +RTS -H10m -K4m Int hashPS ps = foldr f 0 (map (ord.indexPS ps) [1..lengthPS ps]) where f n m = n + m * 128 `mod` 1048583 addToHashTable :: HashTable -> PackedString -> IO () addToHashTable tbl s = do let h = hashPS s index = h `mod` arr_size r <- readArray tbl index if (s `elem` r) then return () else do writeArray tbl index (s : r) elemHashTable :: PackedString -> HashTable -> IO Bool elemHashTable s tbl = do let h = hashPS s index = h `mod` arr_size r <- readArray tbl index return (s `elem` r) \end{code}