From 8b557c36a798e1bc337644a096c7aa6476d2b62d Mon Sep 17 00:00:00 2001
From: dehnert <dehnert@cs.rwth-aachen.de>
Date: Tue, 14 Nov 2017 16:36:52 +0100
Subject: [PATCH] adding murmur3 as a possible hash fct for bit vectors

---
 src/storm/storage/BitVector.cpp      | 60 +++++++++++++++++++++++++++-
 src/storm/storage/BitVector.h        |  7 +++-
 src/storm/storage/BitVectorHashMap.h |  3 +-
 3 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/src/storm/storage/BitVector.cpp b/src/storm/storage/BitVector.cpp
index 924657b44..3b3f9c478 100644
--- a/src/storm/storage/BitVector.cpp
+++ b/src/storm/storage/BitVector.cpp
@@ -1005,8 +1005,8 @@ namespace storm {
         std::size_t FNV1aBitVectorHash::operator()(storm::storage::BitVector const& bv) const {
             std::size_t seed = 14695981039346656037ull;
             
-            unsigned char const* it = reinterpret_cast<unsigned char const*>(bv.buckets);
-            unsigned char const* ite = it + 8 * bv.bucketCount();
+            uint8_t* it = reinterpret_cast<uint8_t*>(bv.buckets);
+            uint8_t const* ite = it + 8 * bv.bucketCount();
             
             while (it < ite) {
                 seed ^= *it++;
@@ -1018,6 +1018,62 @@ namespace storm {
             return seed;
         }
         
+        inline __attribute__((always_inline)) uint32_t fmix32 (uint32_t h) {
+            h ^= h >> 16;
+            h *= 0x85ebca6b;
+            h ^= h >> 13;
+            h *= 0xc2b2ae35;
+            h ^= h >> 16;
+            
+            return h;
+        }
+        
+        inline uint32_t rotl32(uint32_t x, int8_t r) {
+            return (x << r) | (x >> (32 - r));
+        }
+        
+        inline __attribute__((always_inline)) uint32_t getblock32 (uint32_t const* p, int i) {
+            return p[i];
+        }
+        
+        std::size_t Murmur3_32_BitVectorHash::operator()(storm::storage::BitVector const& bv) const {
+            const uint8_t * data = reinterpret_cast<uint8_t const*>(bv.buckets);
+            uint32_t len = bv.bucketCount() * 8;
+            const int nblocks = bv.bucketCount() * 2;
+            
+            // Using 0 as seed.
+            uint32_t h1 = 0;
+            
+            const uint32_t c1 = 0xcc9e2d51;
+            const uint32_t c2 = 0x1b873593;
+            
+            //----------
+            // body
+            
+            const uint32_t * blocks = reinterpret_cast<uint32_t const*>(data + nblocks*4);
+            
+            for (int i = -nblocks; i; i++) {
+                uint32_t k1 = getblock32(blocks, i);
+                
+                k1 *= c1;
+                k1 = rotl32(k1,15);
+                k1 *= c2;
+                
+                h1 ^= k1;
+                h1 = rotl32(h1,13);
+                h1 = h1*5+0xe6546b64;
+            }
+            
+            //----------
+            // finalization
+            
+            h1 ^= len;
+            
+            h1 = fmix32(h1);
+            
+            return h1;
+        }
+        
         // All necessary explicit template instantiations.
         template BitVector::BitVector(uint_fast64_t length, std::vector<uint_fast64_t>::iterator begin, std::vector<uint_fast64_t>::iterator end);
         template BitVector::BitVector(uint_fast64_t length, std::vector<uint_fast64_t>::const_iterator begin, std::vector<uint_fast64_t>::const_iterator end);
diff --git a/src/storm/storage/BitVector.h b/src/storm/storage/BitVector.h
index 17d470eab..8a5c07719 100644
--- a/src/storm/storage/BitVector.h
+++ b/src/storm/storage/BitVector.h
@@ -502,6 +502,7 @@ namespace storm {
             friend std::ostream& operator<<(std::ostream& out, BitVector const& bitVector);
             friend struct std::hash<storm::storage::BitVector>;
             friend struct FNV1aBitVectorHash;
+            friend struct Murmur3_32_BitVectorHash;
             
         private:
             /*!
@@ -574,7 +575,11 @@ namespace storm {
         struct FNV1aBitVectorHash {
             std::size_t operator()(storm::storage::BitVector const& bv) const;
         };
-        
+
+        struct Murmur3_32_BitVectorHash {
+            std::size_t operator()(storm::storage::BitVector const& bv) const;
+        };
+
     } // namespace storage
 } // namespace storm
 
diff --git a/src/storm/storage/BitVectorHashMap.h b/src/storm/storage/BitVectorHashMap.h
index 28eb6c187..ba76e0504 100644
--- a/src/storm/storage/BitVectorHashMap.h
+++ b/src/storm/storage/BitVectorHashMap.h
@@ -15,7 +15,8 @@ namespace storm {
          * 64.
          */
 //        template<typename ValueType, typename Hash = std::hash<storm::storage::BitVector>>
-        template<typename ValueType, typename Hash = FNV1aBitVectorHash>
+//        template<typename ValueType, typename Hash = FNV1aBitVectorHash>
+        template<typename ValueType, typename Hash = Murmur3_32_BitVectorHash>
         class BitVectorHashMap {
         public:
             class BitVectorHashMapIterator {