智能指针的简单实现

Posted 2022-09-17 zuofaqi

template <class T>
class Sp 
public:
    Sp(T* ptr = nullptr) : ptr_(ptr), count_(new size_t) 
        if (ptr) 
            *count_ = 1;
         else 
            *count_ = 0;
        
    

    Sp(const Sp& other) 
        ptr_ = other.ptr_;
        count_ = other.count_;
        (*count_)++;
    

    Sp& operator=(const Sp& src) 
        if (ptr_ == src.ptr_) 
            return *this;
        
        ReleaseCount();
        ptr_ = src.ptr_;
        count_ = src.count_;
        (*count_)++;
        return *this;
    

    size_t use_count() 
        return *count_;
    

    T& operator*() 
        if (ptr_)
        
            return *ptr_;
        
    

    T* operator->() 
        if (ptr_)
        
            return ptr_;
        
    

    operator bool() const 
        return ptr_ != nullptr;
    

    ~Sp() 
        ReleaseCount();
    

private:
    void ReleaseCount() 
        if (ptr_) 
            (*count_)--;
            if (*count_ == 0) 
                delete ptr_;
                delete count_;
            
        
    

    T* ptr_ nullptr;
    size_t* count_ nullptr;
;

class Base

public:
    Base() 
        printf("con\n");
    
    ~Base() 
        printf("decon\n");
    
;