When splitting a bucket, keep the contents in the same order

To retain the property that multiple inserts shadow each other
(see ticket #661, test hash001)

diff --git a/Data/HashTable.hs b/Data/HashTable.hs
index 0f31af5..1463a0d 100644 (file)
--- a/Data/HashTable.hs
+++ b/Data/HashTable.hs
@@ -41,7 +41,7 @@ import Prelude        hiding  ( lookup )
 import Data.Tuple      ( fst )
 import Data.Bits
 import Data.Maybe
-import Data.List       ( maximumBy, filter, length, concat, foldl )
+import Data.List       ( maximumBy, filter, length, concat, foldl, reverse )
 import Data.Int                ( Int32 )
 
 #if defined(__GLASGOW_HASKELL__)
@@ -295,9 +295,9 @@ expandHashTable
    let
     split_bucket old new [] = do
        segment <- myReadArray dir oldsegment
-       myWriteArray segment oldindex old
+       myWriteArray segment oldindex (reverse old)
        segment <- myReadArray dir newsegment
-       myWriteArray segment newindex new
+       myWriteArray segment newindex (reverse new)
     split_bucket old new ((k,v):xs) = do
        h <- bucketIndex table' k
        if h == newbucket