typeinfo.hpp

#ifndef HALCHECK_LIB_RTTI_HPP
#define HALCHECK_LIB_RTTI_HPP
 
#include <halcheck/lib/type_traits.hpp>
 
#include <cstddef>
#include <functional>
#include <type_traits>
 
#if defined(__clang__)
#if __has_feature(cxx_rtti)
#define HALCHECK_RTTI
#endif
#elif defined(__GNUG__)
#if defined(__GXX_RTTI)
#define HALCHECK_RTTI
#endif
#elif defined(_MSC_VER)
#if defined(_CPPRTTI)
#define HALCHECK_RTTI
#endif
#elif HALCHECK_DOXYGEN
#define HALCHECK_RTTI
#endif
 
#ifdef HALCHECK_RTTI
#include <string>
#include <typeinfo> // IWYU pragma: export
#endif
 
namespace halcheck { namespace lib {
 
#ifdef HALCHECK_RTTI
std::string nameof(const std::type_info &info);
 
template<typename T>
std::string nameof() {
  return nameof(typeid(T));
}
#endif
 
struct type_id {
public:
  constexpr type_id() : _index(0) {}
 
  std::size_t hash() const { return std::hash<std::size_t>()(_index); }
 
  template<typename T, HALCHECK_REQUIRE(!std::is_same<T, void>())>
  static type_id of() {
    static const type_id output(next());
    return output;
  }
 
  template<typename T, HALCHECK_REQUIRE(std::is_same<T, void>())>
  static type_id of() {
    return {};
  }
 
private:
  explicit constexpr type_id(std::size_t index) : _index(index) {}
 
  static std::size_t next();
 
  friend bool operator==(const type_id &lhs, const type_id &rhs) { return lhs._index == rhs._index; }
  friend bool operator!=(const type_id &lhs, const type_id &rhs) { return lhs._index != rhs._index; }
  friend bool operator<(const type_id &lhs, const type_id &rhs) { return lhs._index < rhs._index; }
  friend bool operator>(const type_id &lhs, const type_id &rhs) { return lhs._index > rhs._index; }
  friend bool operator<=(const type_id &lhs, const type_id &rhs) { return lhs._index <= rhs._index; }
  friend bool operator>=(const type_id &lhs, const type_id &rhs) { return lhs._index >= rhs._index; }
 
  std::size_t _index;
};
 
}} // namespace halcheck::lib
 
namespace std {
template<>
struct hash<halcheck::lib::type_id> {
  std::size_t operator()(halcheck::lib::type_id value) const { return value.hash(); }
};
} // namespace std
#endif