Add old_boost_hash to benchmark/unordered.cpp

benchmark/unordered.cpp

@@ -163,6 +163,28 @@ template<> struct fnv1a_hash_impl<64>
 
 struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits > {};
 
+// old_boost_hash
+
+class old_boost_hash
+{
+public:
+
+    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
+    {
+        char const * p = st.data();
+        std::size_t n = st.size();
+
+        std::size_t h = 0;
+
+        for( std::size_t i = 0; i < n; ++i )
+        {
+            h ^= static_cast<unsigned char>( p[i] ) + 0x9e3779b9 + ( h << 6 ) + ( h >> 2 );
+        }
+
+        return h;
+    }
+};
+
 //
 
 template<class V, class S> void test4( int N, V const& v, char const * hash, S s )
@@ -295,6 +317,7 @@ int main()
     test2<mul31_hash>( N * 16, v );
     test2<mul31_unrolled_hash>( N * 16, v );
     test2<fnv1a_hash>( N * 16, v );
+    test2<old_boost_hash>( N * 16, v );
     test2<boost::hash<std::string> >( N * 16, v );
     test2<std::hash<std::string> >( N * 16, v );
 
@@ -305,6 +328,7 @@ int main()
     test3<K, mul31_hash>( N, v );
     test3<K, mul31_unrolled_hash>( N, v );
     test3<K, fnv1a_hash>( N, v );
+    test3<K, old_boost_hash>( N, v );
     test3<K, boost::hash<std::string> >( N, v );
     test3<K, std::hash<std::string> >( N, v );