存储器管理

#include <iostream>
#include <vector>
#include <iterator>
using namespace std;
#define MAX_SIZE 1000

struct process{
	int partition_number;//记录分区号
	int size;//进程占用内存大小
	int address;//进程在内存里面的起始地址
	int state;//-1表示还没占用，大于-1的数字表示几号进程在占用
};

class Memory{
public:
	vector<process> vt;//记录已使用进程
	vector<process> free_vt;//记录剩余可分配空间
	Memory();//初始化内存
	void add_mission(int index,int size);//添加任务
	void print_mission();//打印内存中的数据
	void delete_mission(int index);//删除任务
};

Memory::Memory(){
	process tend;
	tend.partition_number = 0;
	tend.size = MAX_SIZE;
	tend.address = 0;
	tend.state = -1;
	free_vt.push_back(tend);
}

void Memory::print_mission(){
	vector<process>::iterator it_vt = vt.begin();//构建进程序列的迭代器
	vector<process>::iterator it_fvt = free_vt.begin();//构建空闲序列的迭代器
	int number = vt.size() + free_vt.size();//记录要打印多少项
	int used = 0;//记录已经使用的内存
	int surplus = 0;//记录还没被使用的内存
	int i = 0;//记录打印次数
	while (i<number){
		if ((it_vt!=vt.end())&&((*it_vt).address < (*it_fvt).address)){//对比地址先输出地址较前的
			used += (*it_vt).size;
			cout << "分区号：" << i
				<< "大小：" << (*it_vt).size
				<< "起址：" << (*it_vt).address
				<< "状态："<<(*it_vt).state<< "号进程占用" ;
			it_vt++;
		}
		else if (it_fvt != free_vt.end()){
			surplus += (*it_fvt).size;
			cout << "分区号：" << i
				<< "大小：" << (*it_fvt).size
				<< "起址：" << (*it_fvt).address
				<< "状态：可用";
			it_fvt++;
		}
		i++;
		cout << endl;
	}
	cout << "已用" << used << "K内存" << endl;
	cout << "剩下" << surplus << "K内存可用" << endl;
}

void Memory::delete_mission(int index){
	vector<process>::iterator it_vt = vt.begin();
	vector<process>::iterator it_fvt = free_vt.begin();
	int size = vt.size();
	/*判断释放区域的各种情况（1）上下都不是空闲区（2）上面是空闲区（3）下面是空闲区（4）上面和下面是空闲区*/
	for (; it_vt != vt.end(); it_vt++){//释放所用内存
		if ((*it_vt).state==index){
			process new_free_block = *it_vt;
			new_free_block.state = -1;
			while ((*it_fvt).address < new_free_block.address){//找到要插入的位置的后面一个
				it_fvt++;
			}
			if ((new_free_block.address + new_free_block.size) == (*it_fvt).address){//（3）修改地址和大小
				(*it_fvt).address = new_free_block.address;
				(*it_fvt).size += new_free_block.size;
			}
			if (it_fvt != free_vt.begin()){
				it_fvt--;
				if (((*it_fvt).address + (*it_fvt).size) == new_free_block.address){//（2）只修改大小
					(*it_fvt).size += new_free_block.size;
					it_fvt++;
					if (new_free_block.address == (*it_fvt).address){//（4）修改大小在（3）时已经修改了地址
						(*(it_fvt - 1)).size = (*(it_fvt - 1)).size + (*it_fvt).size - new_free_block.size ;
						free_vt.erase(it_fvt);
					}
				}
				else{
					if (new_free_block.address != (*(it_fvt+1)).address){
						free_vt.insert(it_fvt, new_free_block); //（1）添加新项目
					}				
				}
			}
			else{
				if (new_free_block.address != (*(it_fvt)).address){
					free_vt.insert(it_fvt, new_free_block); //（1）
				}
			}
			vt.erase(it_vt);
			break;
		}
	}
	if (size == free_vt.size()){
		cout << "无法找到该进程" << endl;
	}
	else{
		cout << "释放" << index << "号进程成功!" << endl;
	}
}

void Memory::add_mission(int index,int size){
	process tend;
	tend.partition_number = -1;
	tend.size = size;
	tend.address = -1;
	tend.state = index;
	vector<process>::iterator it_vt = vt.begin();
	vector<process>::iterator it_fvt = free_vt.begin();
	while (it_fvt != free_vt.end()){
		if (size <= (*it_fvt).size){//找到可以释放的区域
			tend.partition_number = (*it_fvt).partition_number;
			tend.address = (*it_fvt).address;
			process new_free_block;
			new_free_block.partition_number = (*it_fvt).partition_number + 1;
			new_free_block.size = (*it_fvt).size - size;
			new_free_block.address = (*it_fvt).address + size;
			new_free_block.state = -1;
			free_vt.erase(it_fvt);
			it_fvt = free_vt.begin();
			while ((it_fvt!=free_vt.end())&&((*it_fvt).address < new_free_block.address)){//找到要插入的位置
				it_fvt++;
			}
			free_vt.insert(it_fvt,new_free_block);
			break;
		}
		it_fvt++;
	}
	if (tend.address == -1){
		cout << "无可分配的空间" << endl;
	}
	else{
		it_vt = vt.begin();
		while ((it_vt!=vt.end())&&((*it_vt).address < tend.address)){//找到要插入的位置
			it_vt++;
		}
		vt.insert(it_vt, tend);
		cout << tend.state<<"号进程分配成功！分配大小为"<<tend.size <<"K"<< endl;
	}
}

int main(){
	Memory Demo;
	Demo.add_mission(0, 344);
	Demo.add_mission(1, 177);
	Demo.add_mission(2, 148);
	Demo.add_mission(3, 147);
	cout << endl;
	Demo.print_mission();
	Demo.delete_mission(1);
	cout << endl;
	Demo.print_mission();
	Demo.add_mission(4,122);
	cout << endl;
	Demo.print_mission();
	Demo.delete_mission(2);
	cout << endl;
	Demo.print_mission();
	Demo.add_mission(5, 200);
	cout << endl;
	Demo.print_mission();
	Demo.delete_mission(0);
	cout << endl;
	Demo.print_mission();
	Demo.delete_mission(3);
	cout << endl;
	Demo.print_mission();
	return 0;
}