Re: [Boost-users] large variant performance compared (50 elements)

Subject: Re: [Boost-users] large variant performance compared (50 elements)
From: Paul (peebor_at_[hidden])
Date: 2011-01-17 15:18:54

la> [snip]
> Could you post a test driver showing the problem.
> I'd like to see how:

In rough (but working) code:

   class CVisitBinary
     : public static_visitor<bool>
   {
   public:
     template<typename T, typename U>
     bool operator()(const T&, const U&) const
     {
       return false;
     }

     template<typename T>
     bool operator()(const T&, const T&) const
     {
       return true;
     }
   };

template<typename Typelist, typename ElementType1, typename ElementType2>
void TestVariantBinary()
{
   typedef Layout::make_variant_over<Typelist>::type variant_t;

   variant_t v1_1(boost::shared_ptr<ElementType1>(new ElementType1));
   variant_t v1_2(boost::shared_ptr<ElementType1>(new ElementType1));
   variant_t v2_1(boost::shared_ptr<ElementType2>(new ElementType2));
   BOOST_CHECK(apply_visitor(CVisitBinary(), v1_1, v1_2)); //Same type
   BOOST_CHECK(apply_visitor(CVisitBinary(), v1_1, v1_1)); //Same type, 
same instance
   BOOST_CHECK(!apply_visitor(CVisitBinary(), v1_1, v2_1)); //Different 
types
}

//Generate 200 types (class C1, C2, ... C200)
#define BOOST_PP_LOCAL_MACRO(n) \
   class BOOST_PP_CAT(I, n) \
   { \
   public: \
   }; \
   \
   class BOOST_PP_CAT(C, n) \
     : public BOOST_PP_CAT(I, n) \
   { \
   public: \
     int i; \
   };
#define BOOST_PP_LOCAL_LIMITS (0, 200)
#include BOOST_PP_LOCAL_ITERATE()

//Generate mpl sequences
#define SHARED_PTR_C(z, n, data) boost::shared_ptr<BOOST_PP_CAT(C, n)>
#define SHARED_PTR_I(z, n, data) boost::shared_ptr<BOOST_PP_CAT(I, n)>
typedef boost::mpl::vector10<BOOST_PP_ENUM(10, SHARED_PTR_C, 0)> 
MplVectorC10_t;

void test()
{
   TestVariantBinary<MplVectorC10_t, C3, C4>(); //2 phase visitation 
giving 100 paths
}