Traits.hpp

Go to the documentation of this file.

// <Event.h> -*- C++ -*-
 
 
#pragma once
 
#include <type_traits>
 
template <typename T>
class sparta_traits
{
    typedef char yep;
    typedef long nope;
 
    // Determine if the data type has a get() method
    template <typename C> static yep hasGetMethod (decltype(&C::get) );
    template <typename C> static nope hasGetMethod (...);
 
    // Determine if the data type should use -> or . accessors
    template <typename C> static yep hasPointerOperator( decltype(&C::operator->) ) ;
    template <typename C> static nope hasPointerOperator(...);
 
    // Determine if the data type has an iterator type defined
    template <typename C> static typename C::iterator hasIterator(int);
    template <typename> static void hasIterator(...);
 
public:
 
    enum { is_smartptr  = sizeof(hasGetMethod<T>(0)) == sizeof(yep) };
    enum { stl_smartptr = !std::is_void<decltype(hasPointerOperator<T>(0))>::value };
    enum { stl_iterable = !std::is_void<decltype(hasIterator<T>(0))>::value };
 
};
 
template<class value_type>
inline static typename std::enable_if<sparta_traits<value_type>::is_smartptr == false,
                                      const value_type*>::type
getAsPointer(const value_type & obj)
{
    return &obj;
}
 
template<class value_type>
inline static typename std::enable_if<sparta_traits<value_type>::is_smartptr == true,
                                      const typename value_type::element_type*>::type
getAsPointer(const value_type & obj)
{
    return obj.get();
}
 
// template<class value_type>
// inline static typename std::enable_if<std::is_pointer<value_type>::value == true,
//                                       const value_type>::type
// getAsPointer(const value_type & obj)
// {
//     return obj;
// }