common/bloom_filter: insert/contains methods for uint32_t

This will let us pass in an hobject_t::hash directly (for example) without
rehashing a string.

Signed-off-by: Sage Weil <sage@inktank.com>

2 files changed, 73 insertions, 0 deletions

diff --git a/src/common/bloom_filter.hpp b/src/common/bloom_filter.hpp
index 15400b14b9e..6d5f645d8c9 100644
--- a/src/common/bloom_filter.hpp
+++ b/src/common/bloom_filter.hpp
@@ -131,6 +131,17 @@ public:
     inserted_element_count_ = 0;
   }
 
+  inline void insert(uint32_t val) {
+    std::size_t bit_index = 0;
+    std::size_t bit = 0;
+    for (std::size_t i = 0; i < salt_.size(); ++i)
+    {
+      compute_indices(hash_ap(val,salt_[i]),bit_index,bit);
+      bit_table_[bit_index / bits_per_char] |= bit_mask[bit];
+    }
+    ++inserted_element_count_;
+  }
+
   inline void insert(const unsigned char* key_begin, const std::size_t& length)
   {
     std::size_t bit_index = 0;
@@ -170,6 +181,21 @@ public:
     }
   }
 
+  inline virtual bool contains(uint32_t val) const
+  {
+    std::size_t bit_index = 0;
+    std::size_t bit = 0;
+    for (std::size_t i = 0; i < salt_.size(); ++i)
+    {
+      compute_indices(hash_ap(val,salt_[i]),bit_index,bit);
+      if ((bit_table_[bit_index / bits_per_char] & bit_mask[bit]) != bit_mask[bit])
+      {
+        return false;
+      }
+    }
+    return true;
+  }
+
   inline virtual bool contains(const unsigned char* key_begin, const std::size_t length) const
   {
     std::size_t bit_index = 0;
@@ -425,6 +451,15 @@ protected:
     *table_size = t;
   }
 
+  inline bloom_type hash_ap(uint32_t val, bloom_type hash) const
+  {
+    hash ^=    (hash <<  7) ^  ((val & 0xff000000) >> 24) * (hash >> 3);
+    hash ^= (~((hash << 11) + (((val & 0xff0000) >> 16) ^ (hash >> 5))));
+    hash ^=    (hash <<  7) ^  ((val & 0xff00) >> 8) * (hash >> 3);
+    hash ^= (~((hash << 11) + (((val & 0xff)) ^ (hash >> 5))));
+    return hash;
+  }
+
   inline bloom_type hash_ap(const unsigned char* begin, std::size_t remaining_length, bloom_type hash) const
   {
     const unsigned char* itr = begin;
diff --git a/src/test/common/test_bloom_filter.cc b/src/test/common/test_bloom_filter.cc
index 66bda6bcd33..84e2a67a62a 100644
--- a/src/test/common/test_bloom_filter.cc
+++ b/src/test/common/test_bloom_filter.cc
@@ -61,6 +61,44 @@ TEST(BloomFilter, Sweep) {
   }
 }
 
+TEST(BloomFilter, SweepInt) {
+  std::cout << "# max\tfpp\tactual\tsize\tB/insert" << std::endl;
+  for (int ex = 3; ex < 12; ex++) {
+    for (float fpp = .001; fpp < .5; fpp *= 2.0) {
+      int max = 2 << ex;
+      bloom_filter bf(max, fpp, 1);
+      bf.insert("foo");
+      bf.insert("bar");
+
+      ASSERT_TRUE(123);
+      ASSERT_TRUE(456);
+
+      for (int n = 0; n < max; n++)
+	bf.insert(n);
+
+      int test = max * 100;
+      int hit = 0;
+      for (int n = 0; n < test; n++)
+	if (bf.contains(100000 + n))
+	  hit++;
+
+      ASSERT_TRUE(123);
+      ASSERT_TRUE(456);
+
+      double actual = (double)hit / (double)test;
+
+      bufferlist bl;
+      ::encode(bf, bl);
+
+      double byte_per_insert = (double)bl.length() / (double)max;
+
+      std::cout << max << "\t" << fpp << "\t" << actual << "\t" << bl.length() << "\t" << byte_per_insert << std::endl;
+      ASSERT_TRUE(actual < fpp * 10);
+
+    }
+  }
+}
+
 // test the fpp over a sequence of bloom filters, each with unique
 // items inserted into it.
 //