c++ 基础类 type_info 的源码，精简版，cpp20规范

代码太长了，分两个框

struct __type_info_node;
    extern __type_info_node __type_info_root_node;
    
_CRT_BEGIN_C_HEADER

struct __std_type_info_data
{
    const char * _UndecoratedName;
    const char   _DecoratedName[1];
    __std_type_info_data() = delete;
    __std_type_info_data(const __std_type_info_data&) = delete;
    __std_type_info_data(__std_type_info_data&&) = delete;
    __std_type_info_data& operator=(const __std_type_info_data&) = delete;
    __std_type_info_data& operator=(__std_type_info_data&&) = delete;
};
_VCRTIMP int __cdecl __std_type_info_compare( _In_ const __std_type_info_data* _Lhs,  _In_ const __std_type_info_data* _Rhs  );
_VCRTIMP size_t __cdecl __std_type_info_hash(  _In_ const __std_type_info_data* _Data  );
_VCRTIMP const char* __cdecl __std_type_info_name(  _Inout_ __std_type_info_data* _Data,  _Inout_ __type_info_node*     _RootNode  );

_CRT_END_C_HEADER

第二个框：

class type_info
{
private:    mutable __std_type_info_data _Data;
public:
    type_info(const type_info&) = delete;
    type_info& operator=(const type_info&) = delete;

    size_t hash_code() const { return __std_type_info_hash(&_Data); }

    bool operator==(const type_info& _Other) const noexcept
    {  return __std_type_info_compare(&_Data, &_Other._Data) == 0;  }

    bool before(const type_info& _Other) const noexcept
    {  return __std_type_info_compare(&_Data, &_Other._Data) < 0; }

    const char* name() const noexcept
    {  return __std_type_info_name(&_Data, &__type_info_root_node); }

    const char* raw_name() const noexcept
    {  return _Data._DecoratedName; }

    virtual ~type_info() noexcept;
};