Add hash_value for intrusive_ptr. Refs #6087.

[SVN r75392]

include/boost/smart_ptr/intrusive_ptr.hpp

@@ -285,6 +285,15 @@ template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::
 
 #endif // !defined(BOOST_NO_IOSTREAM)
 
+// hash_value
+
+template< class T > struct hash;
+
+template< class T > std::size_t hash_value( boost::intrusive_ptr<T> const & p )
+{
+    return boost::hash< T* >()( p.get() );
+}
+
 } // namespace boost
 
 #endif  // #ifndef BOOST_SMART_PTR_INTRUSIVE_PTR_HPP_INCLUDED

test/Jamfile.v2

@@ -67,5 +67,6 @@ import testing ;
           [ compile make_shared_fp_test.cpp ]
           [ run sp_hash_test.cpp ]
           [ run get_deleter_array_test.cpp ]
+          [ run ip_hash_test.cpp ]
         ;
 }

test/ip_hash_test.cpp

@@ -0,0 +1,75 @@
+//
+// ip_hash_test.cpp
+//
+// Copyright 2011 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+
+#include <boost/intrusive_ptr.hpp>
+#include <boost/functional/hash.hpp>
+#include <boost/detail/lightweight_test.hpp>
+
+class base
+{
+private:
+
+    int use_count_;
+
+    base(base const &);
+    base & operator=(base const &);
+
+protected:
+
+    base(): use_count_(0)
+    {
+    }
+
+    virtual ~base()
+    {
+    }
+
+public:
+
+    long use_count() const
+    {
+        return use_count_;
+    }
+
+    inline friend void intrusive_ptr_add_ref(base * p)
+    {
+        ++p->use_count_;
+    }
+
+    inline friend void intrusive_ptr_release(base * p)
+    {
+        if(--p->use_count_ == 0) delete p;
+    }
+};
+
+struct X: public base
+{
+};
+
+int main()
+{
+    boost::hash< boost::intrusive_ptr<X> > hasher;
+
+    boost::intrusive_ptr<X> p1, p2( p1 ), p3( new X ), p4( p3 ), p5( new X );
+
+    BOOST_TEST_EQ( p1, p2 );
+    BOOST_TEST_EQ( hasher( p1 ), hasher( p2 ) );
+
+    BOOST_TEST_NE( p1, p3 );
+    BOOST_TEST_NE( hasher( p1 ), hasher( p3 ) );
+
+    BOOST_TEST_EQ( p3, p4 );
+    BOOST_TEST_EQ( hasher( p3 ), hasher( p4 ) );
+
+    BOOST_TEST_NE( p3, p5 );
+    BOOST_TEST_NE( hasher( p3 ), hasher( p5 ) );
+
+    return boost::report_errors();
+}