From a20ffc8d13b568b04ee8bab6a90f241987077ed9 Mon Sep 17 00:00:00 2001
From: Justin Bedo <cu@cua0.org>
Date: Wed, 9 Aug 2023 10:20:52 +1000
Subject: hash part of the sequence to add locality

---
 dedumi.hs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dedumi.hs b/dedumi.hs
index 31fd9fe..c529d1c 100644
--- a/dedumi.hs
+++ b/dedumi.hs
@@ -27,6 +27,9 @@ instance CuckooFilterHash ByteString where
 umiLength :: Int
 umiLength = 8
 
+extraHashBases :: Int
+extraHashBases = 4
+
 trim :: ReadPair -> ReadPair
 trim x =
   x
@@ -37,7 +40,7 @@ trim x =
 
 insert' :: (KnownNat b, KnownNat f) => CuckooFilter RealWorld b f ByteString -> ReadPair -> IO Bool
 insert' f x =
-  let y = B.take umiLength (x ^. _1 . nucs) <> B.take umiLength (x ^. _2 . nucs)
+  let y = B.take (umiLength + extraHashBases) (x ^. _1 . nucs) <> B.take (umiLength + extraHashBases) (x ^. _2 . nucs)
    in member f y >>= \case
         True -> pure True
         False ->
-- 
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