Add xmx2_mix

benchmark/uint32.cpp

@@ -292,6 +292,9 @@ template<class K, class V> using boost_unordered_map =
 template<class K, class V> using boost_unordered_flat_map_xmx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx_mix>;
 
+template<class K, class V> using boost_unordered_flat_map_xmx2 =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx2_mix>;
+
 template<class K, class V> using boost_unordered_flat_map_mulx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::mulx_mix>;
 
@@ -319,6 +322,7 @@ int main()
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
     test<boost_unordered_flat_map_xmx>( "boost::unordered_flat_map, xmx" );
+    test<boost_unordered_flat_map_xmx2>( "boost::unordered_flat_map, xmx2" );
     test<boost_unordered_flat_map_mulx>( "boost::unordered_flat_map, mulx" );
 
 #ifdef HAVE_ANKERL_UNORDERED_DENSE
@@ -338,7 +342,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 33 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 34 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uint64.cpp

@@ -292,6 +292,9 @@ template<class K, class V> using boost_unordered_map =
 template<class K, class V> using boost_unordered_flat_map_xmx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx_mix>;
 
+template<class K, class V> using boost_unordered_flat_map_xmx2 =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx2_mix>;
+
 template<class K, class V> using boost_unordered_flat_map_mulx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::mulx_mix>;
 
@@ -329,6 +332,7 @@ int main()
 
     test<boost_unordered_map>( "boost::unordered_map" );
     test<boost_unordered_flat_map_xmx>( "boost::unordered_flat_map, xmx" );
+    test<boost_unordered_flat_map_xmx2>( "boost::unordered_flat_map, xmx2" );
     test<boost_unordered_flat_map_mulx>( "boost::unordered_flat_map, mulx" );
 
 #ifdef HAVE_ANKERL_UNORDERED_DENSE
@@ -348,7 +352,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 33 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 34 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/uuid.cpp

@@ -343,6 +343,9 @@ template<class K, class V> using boost_unordered_map =
 template<class K, class V> using boost_unordered_flat_map_xmx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx_mix>;
 
+template<class K, class V> using boost_unordered_flat_map_xmx2 =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx2_mix>;
+
 template<class K, class V> using boost_unordered_flat_map_mulx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::mulx_mix>;
 
@@ -370,6 +373,7 @@ int main()
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
     test<boost_unordered_flat_map_xmx>( "boost::unordered_flat_map, xmx" );
+    test<boost_unordered_flat_map_xmx2>( "boost::unordered_flat_map, xmx2" );
     test<boost_unordered_flat_map_mulx>( "boost::unordered_flat_map, mulx" );
 
 #ifdef HAVE_ANKERL_UNORDERED_DENSE
@@ -389,7 +393,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 33 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 34 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

benchmark/word_size.cpp

@@ -184,6 +184,9 @@ template<class K, class V> using boost_unordered_map =
 template<class K, class V> using boost_unordered_flat_map_xmx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx_mix>;
 
+template<class K, class V> using boost_unordered_flat_map_xmx2 =
+    boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::xmx2_mix>;
+
 template<class K, class V> using boost_unordered_flat_map_mulx =
     boost::unordered_flat_map<K, V, boost::hash<K>, std::equal_to<K>, allocator_for<K, V>, boost::unordered::detail::foa::mulx_mix>;
 
@@ -211,6 +214,7 @@ int main()
     test<std_unordered_map>( "std::unordered_map" );
     test<boost_unordered_map>( "boost::unordered_map" );
     test<boost_unordered_flat_map_xmx>( "boost::unordered_flat_map, xmx" );
+    test<boost_unordered_flat_map_xmx2>( "boost::unordered_flat_map, xmx2" );
     test<boost_unordered_flat_map_mulx>( "boost::unordered_flat_map, mulx" );
 
 #ifdef HAVE_ANKERL_UNORDERED_DENSE
@@ -230,7 +234,7 @@ int main()
 
     for( auto const& x: times )
     {
-        std::cout << std::setw( 33 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
+        std::cout << std::setw( 34 ) << ( x.label_ + ": " ) << std::setw( 5 ) << x.time_ << " ms, " << std::setw( 9 ) << x.bytes_ << " bytes in " << x.count_ << " allocations\n";
     }
 }
 

include/boost/unordered/detail/foa.hpp

@@ -761,6 +761,15 @@ struct xmx_mix
   }
 };
 
+struct xmx2_mix
+{
+  template<typename Hash,typename T>
+  static inline std::size_t mix(const Hash& h,const T& x)
+  {
+    return xmx2(h(x));
+  }
+};
+
 struct mulx_mix
 {
   template<typename Hash,typename T>

include/boost/unordered/detail/xmx.hpp

@@ -64,6 +64,31 @@ static inline std::size_t xmx(std::size_t x)noexcept
 #endif
 }
 
+// alternative multipliers
+
+static inline std::size_t xmx2( std::size_t x ) noexcept
+{
+#if defined(BOOST_UNORDERED_64B_ARCHITECTURE)
+
+  boost::uint64_t z=(boost::uint64_t)x;
+
+  z ^= z >> 23;
+  z *= 0x9E3779B97F4A7C15ull;
+  z ^= z >> 23;
+
+  return (std::size_t)z;
+
+#else /* 32 bits assumed */
+
+  x ^= x >> 18;
+  x *= 0x9E3779B9u;
+  x ^= x >> 16;
+
+  return x;
+
+#endif
+}
+
 #ifdef BOOST_UNORDERED_64B_ARCHITECTURE
 #undef BOOST_UNORDERED_64B_ARCHITECTURE
 #endif