yorel::yomm2::policy::vptr_map
defined in <yorel/yomm2/policy.hpp>, also provided by <yorel/yomm2/core.hpp>, <yorel/yomm2/keywords.hpp>
template<class Policy>
struct vptr_map;
vptr_map is an implementation of external_vptr that stores the
pointers to the v-tables in a std::unordered_map keyed by the type_ids of
the classes. This makes method dispatch slower than vptr_vector with
fast_perfect_hash (75% slower than native virtual function). However,
vptr_map has some advantages: fast_perfect_hash takes more time to
initialize. It also sacrifices memory space for speed, as it uses a hash
function that is not suitable for perfect and minimal hashing. Using
virtual_ptrs extensively can mitigate the speed disadvantage of vptr_map.
Policy - the policy containing the facet.
| | | | ——————————- | ———————————————– | | dynamic_vptr | return the address of the v-table for an object | | publish_vptrs | store the vptrs |
template<class Policy>
template<class Class>
const std::uintptr_t* vptr_map<Policy>::dynamic_vptr(const Class& object);
Return a pointer to the v-table for object.
Call Policy::dynamic_type for object. Return the vptr associated to the
resulting type_id.
template<class Policy>
template<typename ForwardIterator>
void vptr_map<Policy>::publish_vptrs(ForwardIterator first, ForwardIterator last);
Store the pointers to the v-tables.