From 1576239f67ef2641135f95bdd331f3c1a54ee5ad Mon Sep 17 00:00:00 2001
From: Matthias Vallentin <vallentin@icir.org>
Date: Fri, 14 Jun 2013 10:19:39 -0700
Subject: [PATCH] Support seeding for hashers.

---
 src/BloomFilter.cc | 11 +++++++++++
 src/BloomFilter.h  |  4 +++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/BloomFilter.cc b/src/BloomFilter.cc
index e55db71e46..eff7eee733 100644
--- a/src/BloomFilter.cc
+++ b/src/BloomFilter.cc
@@ -74,6 +74,17 @@ bool CounterVector::DoUnserialize(UnserialInfo* info)
   }
 
 
+HashPolicy::Hasher::Hasher(size_t seed)
+  : h3_(seed)
+{
+}
+
+HashPolicy::HashType
+HashPolicy::Hasher::operator()(const void* x, size_t n) const
+  {
+  return h3_(x, n);
+  }
+
 HashPolicy::HashVector DefaultHashing::Hash(const void* x, size_t n) const
   {
   HashVector h(K(), 0);
diff --git a/src/BloomFilter.h b/src/BloomFilter.h
index 3b5d9efa71..65133621f9 100644
--- a/src/BloomFilter.h
+++ b/src/BloomFilter.h
@@ -96,7 +96,9 @@ protected:
    */
   class Hasher {
   public:
-    HashType operator()(const void* x, size_t n) const { return h3_(x, n); }
+    Hasher(size_t seed);
+
+    HashType operator()(const void* x, size_t n) const;
   private:
     // FIXME: The hardcoded value of 36 comes from UHASH_KEY_SIZE defined in
     // Hash.h. I do not know how this value impacts the hash function behavior