书接上回
由于内容太多,编辑器太卡了,所以分P了
 上P在这里
目录
- 书接上回
 - 备忘录模式
 - 观察者模式
 
备忘录模式
备忘录模式的介绍: https://refactoringguru.cn/design-patterns/memento
 备忘录模式的C++实现: https://refactoringguru.cn/design-patterns/memento/cpp/example
 这个模式还是挺复杂的
 大概的套路就是这样
 原发者自己有保存状态和恢复状态的接口
 负责人做一个统筹,它有一个指针指向待处理的原发者
 它自己的备份和恢复接口内部就调用原发者提供的接口,保存原发者状态到备忘录或者恢复备忘录到原发者(通过创建备忘录类)
 
 C++的代码相对还是好理解的,如果换C语言来写,还是比较复杂的,涉及到动态内存,模拟String功能
 我通过dyad库的动态模板数据类型,做了一个简单的string库
#include <iostream>
#include <string>
#include <vector>
#pragma warning(disable:4996)
//这里借用了dyad[一个单文件的C语言实现的简单的TCP库]中动态数组的实现方法
//借用宏的方式实现了类似C++中模板的感觉
//dyad动态数组
//内存部分
//动态申请
static void* dyad_realloc(void* ptr, int n)
{
	ptr = realloc(ptr, n);
	if ((!ptr) && (n != 0))
	{
		printf("out of mem!!\r\n");
		exit(-1);
	}
	return ptr;
}
//动态释放
static void dyad_free(void* ptr)
{
	free(ptr);
}
//动态数组
#define Vec(T)\
  struct { T *data; int length, capacity; }
#define vec_unpack(v)\
(char**)&(v)->data, &(v)->length, &(v)->capacity, sizeof(*(v)->data)
#define vec_init(v)\
  memset((v), 0, sizeof(*(v)))
#define vec_deinit(v)\
  dyad_free((v)->data)
#define vec_clear(v)\
  ((v)->length = 0)
#define vec_push(v, val)\
  ( vec_expand(vec_unpack(v)),\
    (v)->data[(v)->length++] = (val) )
#define vec_splice(v, start, count)\
  ( vec_splice(vec_unpack(v), start, count),\
    (v)->length -= (count) )
//扩展
static void vec_expand(char** data, int* length, int* capacity, int memsz)
{
	int before = 0;
	if (*length + 1 > *capacity)
	{
		before = *capacity;
		if (*capacity == 0)
		{
			*capacity = 1;
		}
		else
		{
			*capacity <<= 1;//容量翻倍
		}
		*data = (char*)dyad_realloc(*data, *capacity * memsz);
		//注意清空额外申请出来的内存
		memset(*data + before, 0, *capacity / 2);
	}
}
/// <summary>
/// 模拟字符串
/// </summary>
typedef struct
{
	Vec(char) _vec;
}SimString;
//字符串初始化
void SimString_Init(SimString* p, const char* str)
{
	vec_init(&p->_vec);
	for (int i = 0; i < strlen(str); i++)
	{
		vec_push(&p->_vec, str[i]);
	}
}
//获取字符串
void SimString_Get(SimString* p, char* str)
{
	for (int i = 0; i < p->_vec.length; i++)
	{
		str[i] = p->_vec.data[i];
	}
}
//截取字符串
void SimString_Splice(SimString* p, char* str,int start,int end)
{
	if (
		(start < p->_vec.length) 
		&& (end < p->_vec.length) 
		&&(start<end)
		)
	{
		int i = 0;
		for ( i= start; i < end; i++)
		{
			str[i] = p->_vec.data[i];
		}
		//添加结束符
		str[i] = '\0';
	}
}
//拼接
void SimString_Cat(SimString* p, const char* str)
{
	for (int i = 0; i < strlen(str); i++)
	{
		vec_push(&p->_vec, str[i]);
	}
}
/// <summary>
/// 打印字符串
/// </summary>
/// <param name="p"></param>
void SimString_Print(SimString* p)
{
	printf("%s\r\n",p->_vec.data);
	
}
/// <summary>
/// 输出指定长度的字符串
/// </summary>
/// <param name="p"></param>
/// <param name="len"></param>
void SimString_Show(SimString* p, int start,int end)
{
	for (int i = start; (i<p->_vec.length)&&(i < end); i++)
	{
		printf("%c", p->_vec.data[i]);
	}
	printf("\r\n");
}
/// <summary>
/// 拷贝字符串
/// </summary>
/// <param name="dst"></param>
/// <param name="src"></param>
void SimString_Copy(SimString* dst, SimString* src)
{
	vec_init(&dst->_vec);
	for (int i = 0; i < src->_vec.length; i++)
	{
		vec_push(&dst->_vec, src->_vec.data[i]);
	}
}
/
typedef SimString(*FuncPtr)(void*);
typedef struct
{
	FuncPtr GetName;
	FuncPtr date;
	FuncPtr state;
}Memento;
typedef struct
{
	Memento _memento;
	SimString state_;
	SimString date_;
}ConcreteMemento;
SimString ConcreteMemento_date(void* p);
SimString ConcreteMemento_GetName(void* p);
SimString ConcreteMemento_state(void* p);
/// <summary>
/// 初始化
/// </summary>
/// <param name="p"></param>
/// <param name="state"></param>
void ConcreteMemento_Init(ConcreteMemento* p, const char* state)
{
	SimString_Init(&p->state_, state);
	p->_memento.date = ConcreteMemento_date;
	p->_memento.state = ConcreteMemento_state;
	p->_memento.GetName = ConcreteMemento_GetName;
	time_t current_time;
	char* c_time_string;
	/* Get the current time */
	current_time = time(NULL);
	/* Convert to local time format */
	c_time_string = ctime(¤t_time);
	SimString_Init(&p->date_, c_time_string);
}
/// <summary>
/// 返回状态
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
SimString ConcreteMemento_state(void*p)
{
	ConcreteMemento* pp = (ConcreteMemento*)p;
	return pp->state_;
}
/// <summary>
/// 获取名字
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
SimString ConcreteMemento_GetName(void* p)
{
	ConcreteMemento* pp = (ConcreteMemento*)p;
	SimString* ret = (SimString*)malloc(sizeof(SimString));
	
	SimString_Init(ret, pp->date_._vec.data);
	SimString_Cat(ret, "-/-(");
	char* tmp = (char*)malloc(50);
	SimString_Splice(&pp->state_, tmp, 0, 9);
	SimString_Cat(ret, tmp);
	SimString_Cat(ret, "...)");
	free(tmp);
	
	return *ret;
}
/// <summary>
/// 获取日期
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
SimString ConcreteMemento_date(void* p)
{
	ConcreteMemento* pp = (ConcreteMemento*)p;
	return pp->date_;
}
/// <summary>
/// 删除
/// </summary>
/// <param name="p"></param>
void ConcreteMemento_Dele(ConcreteMemento* p)
{
	vec_deinit(&p->date_._vec);
	vec_deinit(&p->state_._vec);
}
typedef struct
{
	SimString state_;
}Originator;
/// <summary>
/// 初始化
/// </summary>
/// <param name="p"></param>
/// <param name="state"></param>
void Originator_Init(Originator*p, const char * state)
{
	SimString_Init(&p->state_, state);
	std::cout << "被记录者: 我的初始状态是: " ;
	SimString_Print(&p->state_);
}
/// <summary>
/// 删除
/// </summary>
/// <param name="p"></param>
void Originator_Del(Originator* p)
{
	vec_deinit(&p->state_._vec);
}
/// <summary>
/// 随机字符串
/// </summary>
/// <param name="length"></param>
/// <returns></returns>
std::string GenerateRandomString(int length) {
	const char alphanum[] =
		"0123456789"
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		"abcdefghijklmnopqrstuvwxyz";
	int stringLength = sizeof(alphanum) - 1;
	std::string random_string;
	for (int i = 0; i < length; i++) {
		random_string += alphanum[std::rand() % stringLength];
	}
	return random_string;
}
/// <summary>
/// 做事
/// </summary>
/// <param name="p"></param>
void Originator_DoSomething(Originator* p)
{
	std::cout << "被记录者: 我希望做些重要的事情\n";
	 SimString_Init( &p->state_ ,GenerateRandomString(30).c_str());
	std::cout << "被记录者: 然后我的状态发生变化了: " ;
	SimString_Print(&p->state_);
}
/// <summary>
/// 保存
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
Memento* Originator_Save(Originator* p)
{
	char* tmp = (char*)malloc(50);
	ConcreteMemento* pp = (ConcreteMemento*)malloc(sizeof(ConcreteMemento));
	SimString_Get(&p->state_, tmp);
	ConcreteMemento_Init(pp, tmp);
	free(tmp);
	return (Memento*)(pp);
}
/// <summary>
/// 恢复
/// </summary>
/// <param name="p"></param>
/// <param name="memento"></param>
void Originator_Restore(Originator* p,Memento* memento)
{   
	ConcreteMemento* pp = (ConcreteMemento*)memento;
	SimString* tmp = (SimString*)malloc(sizeof(SimString));
	SimString_Init(tmp, "xxx");
	SimString_Copy(&pp->state_,tmp);
	std::cout << "被记录者: 我的状态发生变化了: \r\n";
	SimString_Print(&p->state_);
}
typedef struct
{
	std::vector<Memento*> mementos_;
	Originator* originator_;
}Caretaker;
/// <summary>
/// 初始化
/// </summary>
/// <param name="p"></param>
/// <param name="o"></param>
void Caretaker_Init(Caretaker* p, Originator* o)
{
	p->originator_ = o;
}
/// <summary>
/// 删除
/// </summary>
/// <param name="p"></param>
void Caretaker_Dele(Caretaker* p)
{
	for (auto m : p->mementos_) delete m;
}
/// <summary>
/// 备份
/// </summary>
/// <param name="p"></param>
void Caretaker_Backup(Caretaker* p)
{
	std::cout << "\n负责人: 正在保存当前状态...\n";
	p->mementos_.push_back(Originator_Save(p->originator_));
}
/// <summary>
/// 撤销
/// </summary>
/// <param name="p"></param>
void Caretaker_Undo(Caretaker* p) {
	if (!p->mementos_.size()) {
		return;
	}
	Memento* memento = p->mementos_.back();
	p->mementos_.pop_back();
	std::cout << "负责人: 把状态恢复到: ";
	SimString* tmp = (SimString*)malloc(sizeof(SimString));
	*tmp = (ConcreteMemento_GetName(memento));
	SimString_Print(tmp);
	Originator_Restore(p->originator_,memento);
	free(tmp);
}
/// <summary>
/// 显示历史
/// </summary>
/// <param name="p"></param>
void Caretaker_ShowHistory(Caretaker* p)
{
	std::cout << "负责人: 这是目前的记录:\n";
	for (Memento* memento : p->mementos_) {
		SimString* tmp = (SimString*)malloc(sizeof(SimString));
		* tmp = (ConcreteMemento_GetName(memento));
		SimString_Print(tmp);
		free(tmp);
	}
}
void mementoC()
{
	Originator originator;
	Caretaker caretaker;
	Originator_Init(&originator, "Super-duper-super-puper-super.");
	Caretaker_Init(&caretaker, &originator);
	Caretaker_Backup(&caretaker);
	Originator_DoSomething(&originator);
	Caretaker_Backup(&caretaker);
	Originator_DoSomething(&originator);
	Caretaker_Backup(&caretaker);
	Originator_DoSomething(&originator);
	Caretaker_ShowHistory(&caretaker);
	std::cout << "\n客户端: 现在开始回滚!\n\n";
	Caretaker_Undo(&caretaker);
	std::cout << "\n客户端: 现在开始回滚!\n\n";
	Caretaker_Undo(&caretaker);
	Originator_Del(&originator);
	Caretaker_Dele(&caretaker);
}
 
运行结果:
 
观察者模式
观察者模式的介绍: https://refactoringguru.cn/design-patterns/observer
 观察者模式的C++实现: https://refactoringguru.cn/design-patterns/observer/cpp/example
 这个观察者模式也是挺复杂的
 就是观察者内部存在一个指针(C++里是一个引用),这个指针记录着需要观察的对象
 被观察者在执行“通知”操作后,会“通知”到所有的观察者
 如果不希望观察了,观察者提供一个接口,可以移除需要被观察的对象,移除被观察者中记录观察者表对象信息的记录。
 观察者都持有同样的“更新”接口,被观察者拥有同样的“附加”,“移除”,“通知”接口
 C++实现还是相对清晰的,C实现就会比较绕,没有引用和This指针就得换其他的方式模式出来
 上代码:
#include <iostream>
#include <list>
#include <string>
//dyad动态数组
//内存部分
//动态申请
static void* dyad_realloc(void* ptr, int n)
{
	ptr = realloc(ptr, n);
	if ((!ptr) && (n != 0))
	{
		printf("out of mem!!\r\n");
		exit(-1);
	}
	return ptr;
}
//动态释放
static void dyad_free(void* ptr)
{
	free(ptr);
}
//动态数组
#define Vec(T)\
  struct { T *data; int length, capacity; }
#define vec_unpack(v)\
(char**)&(v)->data, &(v)->length, &(v)->capacity, sizeof(*(v)->data)
#define vec_init(v)\
  memset((v), 0, sizeof(*(v)))
#define vec_deinit(v)\
  dyad_free((v)->data)
#define vec_clear(v)\
  ((v)->length = 0)
#define vec_push(v, val)\
  ( vec_expand(vec_unpack(v)),\
    (v)->data[(v)->length++] = (val) )
#define vec_splice(v, start, count)\
  ( vec_splice(vec_unpack(v), start, count),\
    (v)->length -= (count) )
//扩展
static void vec_expand(char** data, int* length, int* capacity, int memsz)
{
	int before = 0;
	if (*length + 1 > *capacity)
	{
		before = *capacity;
		if (*capacity == 0)
		{
			*capacity = 1;
		}
		else
		{
			*capacity <<= 1;//容量翻倍
		}
		*data = (char*)dyad_realloc(*data, *capacity * memsz);
		//注意清空额外申请出来的内存
		memset(*data + before, 0, *capacity / 2);
	}
}
/// <summary>
/// 模拟字符串
/// </summary>
typedef struct
{
	Vec(char) _vec;
}SimString;
//字符串初始化
static void SimString_Init(SimString* p, const char* str)
{
	vec_init(&p->_vec);
	for (int i = 0; i < strlen(str); i++)
	{
		vec_push(&p->_vec, str[i]);
	}
}
//获取字符串
static void SimString_Get(SimString* p, char* str)
{
	for (int i = 0; i < p->_vec.length; i++)
	{
		str[i] = p->_vec.data[i];
	}
}
//截取字符串
static void SimString_Splice(SimString* p, char* str, int start, int end)
{
	if (
		(start < p->_vec.length)
		&& (end < p->_vec.length)
		&& (start < end)
		)
	{
		int i = 0;
		for (i = start; i < end; i++)
		{
			str[i] = p->_vec.data[i];
		}
		//添加结束符
		str[i] = '\0';
	}
}
//拼接
static void SimString_Cat(SimString* p, const char* str)
{
	for (int i = 0; i < strlen(str); i++)
	{
		vec_push(&p->_vec, str[i]);
	}
}
/// <summary>
/// 打印字符串
/// </summary>
/// <param name="p"></param>
static void SimString_Print(SimString* p)
{
	printf("%s\r\n", p->_vec.data);
}
/// <summary>
/// 输出指定长度的字符串
/// </summary>
/// <param name="p"></param>
/// <param name="len"></param>
static void SimString_Show(SimString* p, int start, int end)
{
	for (int i = start; (i < p->_vec.length) && (i < end); i++)
	{
		printf("%c", p->_vec.data[i]);
	}
	printf("\r\n");
}
/// <summary>
/// 拷贝字符串
/// </summary>
/// <param name="dst"></param>
/// <param name="src"></param>
static void SimString_Copy(SimString* dst, SimString* src)
{
	vec_init(&dst->_vec);
	for (int i = 0; i < src->_vec.length; i++)
	{
		vec_push(&dst->_vec, src->_vec.data[i]);
	}
}
/
typedef void(*Update)(void * p,SimString mess);
typedef struct
{
	Update _update;
}IObserver;
typedef void (*Attach)(void* p, IObserver* observer);
typedef void (*Detach)(void* p, IObserver* observer);
typedef void (*Notify)(void* p);
typedef struct
{
	Attach _attach;
	Detach _detach;
	Notify _notify;
}ISubject;
typedef struct
{
	ISubject _isubject;
	std::list<IObserver*> list_observer_;
	SimString message_;
}Subject;
void Subject_Attach(void* p, IObserver* observer);
void Subject_Detach(void* p, IObserver* observer);
void Subject_Notify(void* p);
void Subject_Init(Subject* p)
{
	p->_isubject._attach = Subject_Attach;
	p->_isubject._detach = Subject_Detach;
	p->_isubject._notify = Subject_Notify;
	SimString_Init(&p->message_,"xxx");
}
void Subject_DeInit(Subject* p)
{
	std::cout << "Goodbye, I was the Subject.\n";
}
void Subject_Attach(void* p, IObserver* observer)
{
	Subject* pp = (Subject*)p;
	pp->list_observer_.push_back(observer);
}
void Subject_Detach(void* p, IObserver* observer)
{
	Subject* pp = (Subject*)p;
	pp->list_observer_.remove(observer);
}
void HowManyObserver(Subject *s) {
	std::cout << "There are " << s->list_observer_.size() << " observers in the list.\n";
}
void Subject_Notify(void* p)
{
	Subject* pp = (Subject*)p;
	//通知所有观察者
	std::list<IObserver*>::iterator iterator = pp->list_observer_.begin();
	HowManyObserver(pp);
	while (iterator != pp->list_observer_.end()) {
		(*iterator)->_update((*iterator), pp->message_);
		++iterator;
	}
}
void Subject_CreateMessage(Subject* s,const char * mes)
{
	SimString_Init(&s->message_, mes);
	Subject_Notify(s);
}
void SomeBusinessLogic(Subject* s) {
	SimString_Init(&s->message_, "change message message");
	s->_isubject._notify(s);
	std::cout << "I'm about to do some thing important\n";
}
typedef struct
{
	IObserver _iobserver;
	SimString message_from_subject_;
	Subject * subject_;
	int static_number_;
	int number_;
}Observer;
void Observer_Update(void* p, SimString mess);
static int num = 0;
void Observer_Init(Observer *p,Subject*s)
{
	num++;
	p->_iobserver._update = Observer_Update;
	p->subject_ = s;
	p->subject_->_isubject._attach = Subject_Attach;
	p->subject_->_isubject._detach = Subject_Detach;
	p->subject_->_isubject._notify = Subject_Notify;
	p->subject_->list_observer_ = s->list_observer_;
	SimString_Copy(&p->subject_->message_, &s->message_);
	p->subject_->_isubject._attach = s->_isubject._attach;
	p->subject_->_isubject._detach = s->_isubject._detach;
	p->subject_->_isubject._notify = s->_isubject._notify;
	p->subject_->_isubject._attach(s, &p->_iobserver);
	p->number_ = num;
	p->static_number_ = num;
	std::cout << "Hi, I'm the Observer \"" <<
		p->static_number_ << "\".\n";
}
void Observer_DeInit(Observer* p)
{
	std::cout << "Goodbye, I was the Observer \"" << p->number_ << "\".\n";
}
void PrintInfo(Observer* p) {
	std::cout << "Observer \""
		<< p->number_ << "\": a new message is available --> ";
	SimString_Print(&p->message_from_subject_);
	
}
void Observer_Update(void* p, SimString mess)
{
	Observer* pp = (Observer*)p;
	SimString_Init(&pp->message_from_subject_, mess._vec.data);
	PrintInfo(pp);
}
void Observer_RemoveMeFromTheList(Observer* p) {
	p->subject_->_isubject._detach(p->subject_,&p->_iobserver);
	std::cout << "Observer \"" << p->number_ 
		<< "\" removed from the list.\n";
}
static void ClientCode()
{
	Subject subject;
	Subject_Init(&subject);
	Observer ob1,ob2,ob3,ob4,ob5;
	Observer_Init(&ob1,&subject);
	Observer_Init(&ob2, &subject);
	Observer_Init(&ob3, &subject);
	Subject_CreateMessage(&subject, "Hello World! :D");
	Observer_RemoveMeFromTheList(&ob3);
	Subject_CreateMessage(&subject, "The weather is hot today! :p");
	Observer_Init(&ob4, &subject);
	Observer_RemoveMeFromTheList(&ob2);
	Observer_Init(&ob5, &subject);
	Subject_CreateMessage(&subject, "My new car is great! ;)");
	Observer_RemoveMeFromTheList(&ob5);
	Observer_RemoveMeFromTheList(&ob4);
	Observer_RemoveMeFromTheList(&ob1);
	Observer_DeInit(&ob1);
	Observer_DeInit(&ob2);
	Observer_DeInit(&ob3);
	Observer_DeInit(&ob4);
	Observer_DeInit(&ob5);
	Subject_DeInit(&subject);
}
void ObserverC() {
	ClientCode();
}
 







![[陇剑杯 2021]之Misc篇(NSSCTF)刷题记录④](https://img-blog.csdnimg.cn/70ede0abb56241d480e636535a33db45.png)












