type_id.h

#ifndef __VECS_TYPE_ID_H__
#define __VECS_TYPE_ID_H__
 
#include <cstddef>
#include <type_traits>
 
#include "dynamic_bitset.h"
 
namespace vecs {
 
using Entity = size_t;
using ComponentId = size_t;
using ComponentMask = storage::dynamic_bitset;
 
class TypeIDGenerator {
  public:
    template<typename T>
    static std::size_t get_type_id() {
        return get_decayed_type_id<std::decay_t<T>>();
    }
 
  private:
    template<typename DecayedT>
    static std::size_t get_decayed_type_id() {
        static std::size_t type_id = m_counter++;
        return type_id;
    }
 
    static std::size_t m_counter;
};
 
template<typename... Components>
ComponentMask compute_mask() {
    ComponentMask mask;
    (mask.set(TypeIDGenerator::get_type_id<Components>()), ...);
    return mask;
}
 
}  // namespace vecs
 
#endif