conversion_veneer.hpp

用STL的方式封装了WindowsAPI、COM调用、ACE、ATL、MFC、WTL等多种组件

    {
        return reinterpret_cast<conversion_type&>(v);
    }

    /// Converts a reference-to-const to the \c value_type to a reference-to-const to the \c conversion_type
    static conversion_type const &convert_const_reference(value_type const &v)
    {
        return reinterpret_cast<conversion_type const&>(v);
    }

    /// Pointer conversion type
    struct pointer_conversion
    {
        conversion_type *operator ()(value_type *pv)
        {
            return convert_pointer(pv);
        }
    };

    /// Pointer-to-const conversion type
    struct pointer_const_conversion
    {
        conversion_type const *operator ()(value_type const *pv)
        {
            return convert_const_pointer(pv);
        }
    };

    /// Reference conversion type
    struct reference_conversion
    {
        conversion_type &operator ()(value_type &v)
        {
            return convert_reference(v);
        }
    };

    /// Reference-to-const conversion type
    struct reference_const_conversion
    {
        conversion_type const &operator ()(value_type const &v)
        {
            return convert_const_reference(v);
        }
    };

};

// class c_conversion
/// Implements conversion via C-style casts
///
/// \param T The value type
/// \param C The conversion type
template<   ss_typename_param_k T
        ,   ss_typename_param_k C
        >
struct c_conversion
{
public:
    /// The value type
    typedef T       value_type;
    /// The conversion type
    typedef C       conversion_type;

public:
    /// Converts a pointer to the \c value_type to a pointer to the \c conversion_type
    static conversion_type *convert_pointer(value_type *pv)
    {
        return (conversion_type*)(pv);
    }

    /// Converts a pointer-to-const to the \c value_type to a pointer-to-const to the \c conversion_type
    static conversion_type const *convert_const_pointer(value_type const *pv)
    {
        return (conversion_type const*)(pv);
    }

    /// Converts a reference to the \c value_type to a reference to the \c conversion_type
    static conversion_type &convert_reference(value_type &v)
    {
        return (conversion_type&)(v);
    }

    /// Converts a reference-to-const to the \c value_type to a reference-to-const to the \c conversion_type
    static conversion_type const &convert_const_reference(value_type const &v)
    {
        return (conversion_type const&)(v);
    }

    /// Pointer conversion type
    struct pointer_conversion
    {
        conversion_type *operator ()(value_type *pv)
        {
            return convert_pointer(pv);
        }
    };

    /// Pointer-to-const conversion type
    struct pointer_const_conversion
    {
        conversion_type const *operator ()(value_type const *pv)
        {
            return convert_const_pointer(pv);
        }
    };

    /// Reference conversion type
    struct reference_conversion
    {
        conversion_type &operator ()(value_type &v)
        {
            return convert_reference(v);
        }
    };

    /// Reference-to-const conversion type
    struct reference_const_conversion
    {
        conversion_type const &operator ()(value_type const &v)
        {
            return convert_const_reference(v);
        }
    };

};

// class conversion_veneer
/// This class allows policy-based control of the four conversions: pointer, non-mutable pointer, reference, non-mutable reference
///
/// \param T The type that will be subjected to the <a href = "http://synesis.com.au/resources/articles/cpp/veneers.pdf">veneer</a>
/// \param C The type that T will be converted to
/// \param V The value type. On translators that support default template arguments this defaults to T.
/// \param P The type that controls the pointer conversion
/// \param R The type that controls the reference conversion
/// \param PC The type that controls the pointer-to-const conversion
/// \param RC The type that controls the reference-to-const conversion
///
/// \ingroup concepts_veneer
template<   ss_typename_param_k T
        ,   ss_typename_param_k C
#ifdef STLSOFT_CF_TEMPLATE_CLASS_DEFAULT_FUNDAMENTAL_ARGUMENT_SUPPORT
        ,   ss_typename_param_k V = T
        ,   ss_typename_param_k P = invalid_conversion<T, C>
        ,   ss_typename_param_k R = invalid_conversion<T, C>
        ,   ss_typename_param_k PC = P
        ,   ss_typename_param_k RC = R
#else
        ,   ss_typename_param_k V
        ,   ss_typename_param_k P
        ,   ss_typename_param_k R
        ,   ss_typename_param_k PC
        ,   ss_typename_param_k RC
#endif /* STLSOFT_CF_TEMPLATE_CLASS_DEFAULT_FUNDAMENTAL_ARGUMENT_SUPPORT */
        >
class conversion_veneer
    : public T
{
public:
    /// The parent class type
    typedef T                                                   parent_class_type;
    /// The conversion type
    typedef C                                                   conversion_type;
    /// The value type
    typedef V                                                   value_type;
    /// The pointer conversion type
    typedef ss_typename_type_k P::pointer_conversion            pointer_conversion_type;
    /// The reference conversion type
    typedef ss_typename_type_k R::reference_conversion          reference_conversion_type;
    /// The pointer-to-const conversion type
    typedef ss_typename_type_k PC::pointer_const_conversion     pointer_const_conversion_type;
    /// The reference-to-const conversion type
    typedef ss_typename_type_k RC::reference_const_conversion   reference_const_conversion_type;
    /// The current parameterisation of the type
    typedef conversion_veneer<T, C, V, P, R, PC, RC>            class_type;

// Construction
public:
    /// The default constructor
    conversion_veneer()
    {
        stlsoft_constraint_must_be_same_size(T, class_type);
    }

    /// The copy constructor
    conversion_veneer(class_type const &rhs)
        : parent_class_type(rhs)
    {
        stlsoft_constraint_must_be_same_size(T, class_type);
    }

    /// Initialise from a value
    conversion_veneer(value_type const &rhs)
        : parent_class_type(rhs)
    {
        stlsoft_constraint_must_be_same_size(T, class_type);
    }

#ifdef STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT
    // For compilers that support member templates, the following constructors
    // are provided.

    /// Single parameter constructor
    template <ss_typename_param_k N1>
    ss_explicit_k conversion_veneer(N1 &n1)
        : parent_class_type(n1)
    {}
    /// Single parameter constructor
    template <ss_typename_param_k N1>
    ss_explicit_k conversion_veneer(N1 *n1)
        : parent_class_type(n1)
    {}

    /// Two parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2>
    conversion_veneer(N1 n1, N2 n2)
        : parent_class_type(n1, n2)
    {}

    /// Three parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3>
    conversion_veneer(N1 n1, N2 n2, N3 n3)
        : parent_class_type(n1, n2, n3)
    {}

    /// Four parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3, ss_typename_param_k N4>
    conversion_veneer(N1 n1, N2 n2, N3 n3, N4 n4)
        : parent_class_type(n1, n2, n3, n4)
    {}

    /// Five parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3, ss_typename_param_k N4, ss_typename_param_k N5>
    conversion_veneer(N1 n1, N2 n2, N3 n3, N4 n4, N5 n5)
        : parent_class_type(n1, n2, n3, n4, n5)
    {}

    /// Six parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3, ss_typename_param_k N4, ss_typename_param_k N5, ss_typename_param_k N6>
    conversion_veneer(N1 n1, N2 n2, N3 n3, N4 n4, N5 n5, N6 n6)
        : parent_class_type(n1, n2, n3, n4, n5, n6)
    {}

    /// Seven parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3, ss_typename_param_k N4, ss_typename_param_k N5, ss_typename_param_k N6, ss_typename_param_k N7>
    conversion_veneer(N1 n1, N2 n2, N3 n3, N4 n4, N5 n5, N6 n6, N7 n7)
        : parent_class_type(n1, n2, n3, n4, n5, n6, n7)
    {}

    /// Eight parameter constructor
    template <ss_typename_param_k N1, ss_typename_param_k N2, ss_typename_param_k N3, ss_typename_param_k N4, ss_typename_param_k N5, ss_typename_param_k N6, ss_typename_param_k N7, ss_typename_param_k N8>
    conversion_veneer(N1 n1, N2 n2, N3 n3, N4 n4, N5 n5, N6 n6, N7 n7, N8 n8)
        : parent_class_type(n1, n2, n3, n4, n5, n6, n7, n8)
    {}
#endif // STLSOFT_CF_MEMBER_TEMPLATE_CTOR_SUPPORT

    /// Copy assignment operator
    class_type &operator =(class_type const &rhs)
    {
        static_cast<parent_class_type&>(*this) = rhs;

        return *this;
    }

    /// Copy from a value
    class_type &operator =(value_type const &rhs)
    {
        static_cast<parent_class_type&>(*this) = rhs;

        return *this;
    }

#ifdef STLSOFT_CF_MEMBER_TEMPLATE_FUNCTION_SUPPORT
    /// Copy from a value
    template <ss_typename_param_k T1>
    class_type &operator =(T1 rhs)
    {
        static_cast<parent_class_type&>(*this) = rhs;

        return *this;
    }
#endif // STLSOFT_CF_MEMBER_TEMPLATE_FUNCTION_SUPPORT

    // Note that the copy constructor is not defined, and will NOT be defined copy ctor/operator not made

// Conversions
public:
    /// Implicit conversion to a reference to the conversion_type
    operator conversion_type &()
    {
        return reference_conversion_type()(*this);
    }
    /// Implicit conversion to a reference-to-const to the conversion_type
    operator conversion_type const &() const
    {
        return reference_const_conversion_type()(*this);
    }

    /// Address-of operator, returning a pointer to the conversion type
    conversion_type * operator &()
    {
        // Take a local reference, such that the application of the address-of
        // operator will allow user-defined conversions of the parent_class_type
        // to be applied.
        parent_class_type   &_this  =   *this;

        return pointer_conversion_type()(&_this);
    }
    /// Address-of operator, returning a pointer-to-const to the conversion type
    conversion_type const * operator &() const
    {
        // Take a local reference, such that the application of the address-of
        // operator will allow user-defined conversions of the parent_class_type
        // to be applied.
        parent_class_type const &_this  =   *this;

        return pointer_const_conversion_type()(&_this);
    }
};

/* ////////////////////////////////////////////////////////////////////// */

#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */

/* ////////////////////////////////////////////////////////////////////// */

#endif /* !STLSOFT_INCL_STLSOFT_OBSOLETE_HPP_CONVERSION_VENEER */

/* ////////////////////////////////////////////////////////////////////// */