concatenate.h

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#pragma once
 
#include <type_traits>
 
namespace pcl
{
  /** \brief Helper functor structure for concatenate. 
    * \ingroup common
    */
  template<typename PointInT, typename PointOutT>
  struct NdConcatenateFunctor
  {
    using PodIn = typename traits::POD<PointInT>::type;
    using PodOut = typename traits::POD<PointOutT>::type;
    
    NdConcatenateFunctor (const PointInT &p1, PointOutT &p2)
      : p1_ (reinterpret_cast<const PodIn&> (p1))
      , p2_ (reinterpret_cast<PodOut&> (p2)) { }
 
    template<typename Key> inline void 
    operator () ()
    {
      // This sucks without Fusion :(
      //boost::fusion::at_key<Key> (p2_) = boost::fusion::at_key<Key> (p1_);
      using InT = typename pcl::traits::datatype<PointInT, Key>::type;
      using OutT = typename pcl::traits::datatype<PointOutT, Key>::type;
      // Note: don't currently support different types for the same field (e.g. converting double to float)
      BOOST_MPL_ASSERT_MSG ((std::is_same<InT, OutT>::value),
                            POINT_IN_AND_POINT_OUT_HAVE_DIFFERENT_TYPES_FOR_FIELD,
                            (Key, PointInT&, InT, PointOutT&, OutT));
      memcpy (reinterpret_cast<std::uint8_t*>(&p2_) + pcl::traits::offset<PointOutT, Key>::value,
              reinterpret_cast<const std::uint8_t*>(&p1_) + pcl::traits::offset<PointInT, Key>::value,
              sizeof (InT));
    }
 
    private:
      const PodIn &p1_;
      PodOut &p2_;
  };
}