C++函数中，两个自动释放内存的动态内存申请类
- 2019 年 10 月 3 日
- 笔记
最近做一个事情，实现一个流程交互，其中主交互流程函数中，涉及较多的内存申请，
而健康的函数，都是在函数退出前将手动申请不再需要的内存释放掉，
使用很多方法，都避免不了较多的出错分支时，一堆的if free/delete，代码长而且不好管理
因此，利用C++对象离开作用域会自动调用析构函数的特点，在这儿实现了两个自动释放内存的动态内存申请类
第一个类，只管理内存，不并管理对象
#include <vector> class XAutoFreeMem { protected: std::vector<void*> vec_memorys_; public: XAutoFreeMem::XAutoFreeMem() {}; virtual XAutoFreeMem::~XAutoFreeMem() { //释放对象时，释放管理的内存 for(auto item : vec_memorys_){ free(item); } } //通过此接口来申请内存 void* malloc_mem(unsigned int nsize) { void* ptr = malloc(nsize); if (nullptr != ptr) { vec_memorys_.push_back(ptr); } return ptr; } };
第二个类，能够同时支持内存管理、对象管理
typedef void (*delete_obj_func)(void*); class XAutoFreeObject : public XAutoFreeMem { private: typedef struct object_manager_st { void* obj_this; delete_obj_func delete_ptr; }object_manager_st; protected: template<typename T> static void free_object(T* p_this) { delete p_this; } template<typename T> static void free_objects(T* p_this) { delete []p_this; } protected: std::vector<object_manager_st> vec_objects_; public: XAutoFreeObject::XAutoFreeObject() {}; virtual XAutoFreeObject::~XAutoFreeObject() { //释放对象时，释放管理的对象 for(auto item : vec_objects_){ (*item.delete_ptr)(item.obj_this); } } //对象 //通过此接口来创建对象 template<typename T> void new_object(T** ppObj) { object_manager_st stObjMan; stObjMan.obj_this = new T; if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr =(delete_obj_func) & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } *ppObj = (T*)(stObjMan.obj_this); return; } //通过此接口来创建对象 template<typename T, typename P> void new_object_with_param(T** ppObj, P param) { object_manager_st stObjMan; stObjMan.obj_this = new T(param); if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr = & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } *ppObj = (T*)(stObjMan.obj_this); return; } //通过此接口来创建对象，这几个接口使用会麻烦一些，使用示例：std::string* pstr = stAutoManager.new_object<std::string> (); template<typename T> T* new_object() { object_manager_st stObjMan; stObjMan.obj_this = new T; if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr =(delete_obj_func) & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } return (T*)(stObjMan.obj_this); } //通过此接口来创建对象 template<typename T, typename P> T* new_object_with_param(P param) { object_manager_st stObjMan; stObjMan.obj_this = new T(param); if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr = & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } return (T*)(stObjMan.obj_this); } //对象数组 //通过此接口来创建对象数组 template<typename T> void new_objects(T** ppObj, int num) { object_manager_st stObjMan; stObjMan.obj_this = new T[num]; if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr =(delete_obj_func) & free_objects<T>; //保存之 vec_objects_.push_back(stObjMan); } *ppObj = (T*)(stObjMan.obj_this); return; } //通过此接口来创建对象数组 template<typename T, typename P> void new_objects_with_param(T** ppObj, int num, P param) { object_manager_st stObjMan; stObjMan.obj_this = new T[num](param); if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr = & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } *ppObj = (T*)(stObjMan.obj_this); return; } //通过此接口来创建对象数组 template<typename T> T* new_objects(int num) { object_manager_st stObjMan; stObjMan.obj_this = new T[num]; if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr =(delete_obj_func) & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } return (T*)(stObjMan.obj_this); } //通过此接口来创建对象数组 template<typename T, typename P> T* new_objects_with_param(int num, P param) { object_manager_st stObjMan; stObjMan.obj_this = new T[num](param); if (nullptr != stObjMan.obj_this) { //取得函数指针 stObjMan.delete_ptr = & free_object<T>; //保存之 vec_objects_.push_back(stObjMan); } return (T*)(stObjMan.obj_this); } };
调用示例如下：
int main(int argc, char* argv[]) { //cwSL3D_test_sum();//测试能否成功调用所有接口 XAutoFreeObject stAutoManager; char* strMem = (char*)stAutoManager.malloc_mem(100); std::string* pstr = stAutoManager.new_object<std::string> (); std::string* pstr2 = nullptr; stAutoManager.new_object(&pstr2); { std::vector<int>* pvec = nullptr; stAutoManager.new_object(&pvec); std::vector<int>* pvec2 = nullptr; stAutoManager.new_objects(&pvec, 2); } return 0; }
