[boost] mpl::begin<mpl::vector<...> > performance problem

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2005-02-23 09:43:03

Hi all,

I am having a huge compile performance problem trying to use mpl::begin for
an mpl::vector of a large size -- the complexity seems to be far from
constant (or even linear) time.  The following example demonstrates it (I am
using GCC 3.3.3 or 3.4.2)

----------
#define BOOST_TYPEOF_LIMIT_SIZE 200

#include "boost/mpl/vector.hpp"
#include "boost/mpl/size_t.hpp"
#include "boost/mpl/begin_end.hpp"
#include "boost/mpl/aux_/config/ctps.hpp"
#include "boost/preprocessor/iterate.hpp"
#include "boost/preprocessor/if.hpp"
#include "boost/preprocessor/repetition/enum.hpp"
#include "boost/config.hpp"

#if (BOOST_TYPEOF_LIMIT_SIZE > BOOST_MPL_LIMIT_VECTOR_SIZE)

#warning started generating

namespace boost
{
namespace mpl
{
    #define BOOST_PP_ITERATION_PARAMS_1 (3,( \
        BOOST_PP_INC(BOOST_MPL_LIMIT_VECTOR_SIZE), \
        BOOST_TYPEOF_LIMIT_SIZE, \
        "boost/mpl/vector/aux_/numbered.hpp"))
    #include BOOST_PP_ITERATE()
}
}

#warning done generating

#endif//BOOST_TYPEOF_LIMIT_SIZE > BOOST_MPL_LIMIT_VECTOR_SIZE

#define MACRO(z, n, _)\
boost::mpl::size_t<n>

#warning started getting begin
typedef boost::mpl::begin<BOOST_PP_CAT(boost::mpl::vector,
BOOST_TYPEOF_LIMIT_SIZE)<
BOOST_PP_ENUM(BOOST_TYPEOF_LIMIT_SIZE, MACRO, ~)
> >::type it;
#warning done getting begin

main()
{}
---------------

Thanks in advance for any help.

Regards,
Arkadiy