comprecpp/cppbase/STL/smart_ptr.h

#pragma once

#include "../ex_object.h"

// 基本
void base();

// 自定义一个简单的智能指针
template <typename T>
class MSmartPointer {
private:
    T*      ptr;
    size_t* refCount;

public:
    MSmartPointer() : ptr(nullptr), refCount(nullptr) {}

    explicit MSmartPointer(T* p) : ptr(p), refCount(new size_t(1)) {}

    // 拷贝构造函数
    MSmartPointer(const MSmartPointer& other)
        : ptr(other.ptr), refCount(other.refCount)
    {
        if (!refCount) {
            return;
        }
        ++(*refCount);
    }

    // 析构函数
    ~MSmartPointer()
    {
        if (refCount && --(*refCount) <= 0) {
            delete ptr;
            delete refCount;
            ptr = nullptr;
            refCount = nullptr;
        }
    }

    // 重载赋值操作符
    MSmartPointer& operator=(const MSmartPointer& other)
    {
        if (this == &other) {
            return *this;
        }

        if (refCount && --(*refCount) <= 0) {
            delete ptr;
            delete refCount;
        }

        ptr = other.ptr;
        refCount = other.refCount;

        if (refCount) {
            ++(*refCount);
        }
        return *this;
    }

    T& operator*() const { return *ptr; }
    T* operator->() const { return ptr; }
};

// 测试用例
void test_example();