1 // Copyright David Abrahams 2002. 2 // Distributed under the Boost Software License, Version 1.0. (See 3 // accompanying file LICENSE_1_0.txt or copy at 4 // http://www.boost.org/LICENSE_1_0.txt) 5 #ifndef BACK_REFERENCE_DWA2002510_HPP 6 # define BACK_REFERENCE_DWA2002510_HPP 7 8 # include <boost/python/detail/prefix.hpp> 9 10 # include <boost/python/object_fwd.hpp> 11 # include <boost/python/detail/dependent.hpp> 12 # include <boost/python/detail/raw_pyobject.hpp> 13 14 namespace boost { namespace python { 15 16 template <class T> 17 struct back_reference 18 { 19 private: // types 20 typedef typename detail::dependent<object,T>::type source_t; 21 public: 22 typedef T type; 23 24 back_reference(PyObject*, T); 25 source_t const& source() const; 26 T get() const; 27 private: 28 source_t m_source; 29 T m_value; 30 }; 31 32 # ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION 33 template<typename T> 34 class is_back_reference 35 { 36 public: 37 BOOST_STATIC_CONSTANT(bool, value = false); 38 }; 39 40 template<typename T> 41 class is_back_reference<back_reference<T> > 42 { 43 public: 44 BOOST_STATIC_CONSTANT(bool, value = true); 45 }; 46 47 # else // no partial specialization 48 49 }} // namespace boost::python 50 51 #include <boost/type.hpp> 52 53 namespace boost { namespace python { 54 55 namespace detail 56 { 57 typedef char (&yes_back_reference_t)[1]; 58 typedef char (&no_back_reference_t)[2]; 59 60 no_back_reference_t is_back_reference_test(...); 61 62 template<typename T> 63 yes_back_reference_t is_back_reference_test(boost::type< back_reference<T> >); 64 } 65 66 template<typename T> 67 class is_back_reference 68 { 69 public: 70 BOOST_STATIC_CONSTANT( 71 bool, value = ( 72 sizeof(detail::is_back_reference_test(boost::type<T>())) 73 == sizeof(detail::yes_back_reference_t))); 74 }; 75 76 # endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION 77 78 // 79 // implementations 80 // 81 template <class T> back_reference(PyObject * p,T x)82back_reference<T>::back_reference(PyObject* p, T x) 83 : m_source(detail::borrowed_reference(p)) 84 , m_value(x) 85 { 86 } 87 88 template <class T> source() const89typename back_reference<T>::source_t const& back_reference<T>::source() const 90 { 91 return m_source; 92 } 93 94 template <class T> get() const95T back_reference<T>::get() const 96 { 97 return m_value; 98 } 99 100 }} // namespace boost::python 101 102 #endif // BACK_REFERENCE_DWA2002510_HPP 103