comparison_operators.hpp

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#pragma once
#define __XTD_STD_INTERNAL__
#include "../internal/__xtd_std_version.hpp"
#undef __XTD_STD_INTERNAL__
#include <compare>
 
namespace xtd {
  namespace extensions {
    template<class type_t, class comparable_t>
    class comparison_operators {
    public:
      
      friend bool operator <(const type_t& lhs, const type_t& rhs) noexcept {
        auto rhs_ptr = &rhs;
        return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) < 0;
      }
      
      friend bool operator <=(const type_t& lhs, const type_t& rhs) noexcept {
        auto rhs_ptr = &rhs;
        return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) <= 0;
      }
      
      friend bool operator >(const type_t& lhs, const type_t& rhs) noexcept {
        auto rhs_ptr = &rhs;
        return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) > 0;
      }
      
      friend bool operator >=(const type_t& lhs, const type_t& rhs) noexcept {
        auto rhs_ptr = &rhs;
        return dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) >= 0;
      }
      
#if defined(__xtd__cpp_lib_three_way_comparison)
      friend std::strong_ordering operator <=>(const type_t& lhs, const type_t& rhs) noexcept {
        auto rhs_ptr = &rhs;
        if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) < 0) return std::strong_ordering::less;
        if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) > 0) return std::strong_ordering::greater;
        if (dynamic_cast<const type_t*>(rhs_ptr) && lhs.compare_to(static_cast<const type_t&>(rhs)) == 0) return std::strong_ordering::equivalent;
        return std::strong_ordering::less;
      }
#endif
    
    private:
      friend comparable_t;
      comparison_operators() = default;
    };
  }
}