unix.cpp

模拟了一个简单的UNIX文件系统

typedef struct sys
{
	int i;
	char dect[20];
	char memo[20];
	char name[10];
	struct sys *next;
}sys;

typedef struct User
{
	char name[10];
	char password[10];
}User;

typedef struct Files
{
	int num;
	char name[10];
	int p;
	int length;
	char mode[20];
	char fadect[20];
	struct Files *next;
}Files;
#include <string.h>
#include <iostream.h>
#include <iomanip.h>

//系统初始提供的两个用户名和密码
User defaultUser[2] =
{
	"user1","123",
	"user2","456"
};

//全局变量
User *user;     
Files *file;
sys *myfile;  
int nUserNo=0;
int no;
int fnode=0; 
char current[20];   //当前目录
char predect[20];   //上级目录
char nowdir[200];   //当前绝对路径
int used;

//验证用户名和密码
bool checkUser(char* username, char* password)
{
	int i;
	for(i=0; i<8; i++)
	{
		if( (strcmp(username,defaultUser[i].name)==0)
			&& (strcmp(password,defaultUser[i].password)==0)
			)
			return true;
	}
	return false;
}

//创建文件
sys* createFile()
{
	int L=0;
	sys *ps1;
	sys *pend1;
	ps1=new sys; 
	ps1->i=0;
	strcpy(ps1->name,"root");    
	myfile=NULL;
	pend1=ps1;    
	while(L!=1)
	{
		L=L+1;
		if (myfile==NULL)
			myfile=ps1;
		else
			pend1->next =ps1;  
		pend1=ps1;
		ps1=new sys;
		ps1->i =1;
		strcpy(ps1->name ,"lin");  
    } 
	pend1->next=NULL;
	delete ps1;
	return(myfile);
}

//查看帮助信息
void help(void)
{
	cout<<"********************************帮助信息**********************************"<< endl;
	cout<<"dir--显示文件和目录"<<endl; 
	cout<<"create--创建新文件和编辑文件"<<endl;
	cout<<"cd--改变当前目录"<<endl;
	cout<<"mkdir--创建新目录"<<endl;
	cout<<"open--打开显示文件"<<endl;
	cout<<"delete--删除文件"<<endl;
	cout<<"logout--退出系统"<<endl;
	cout<< "__"<<endl;
}
//获取文件长度
long filelength=0;
void getlen(sys *myfile,char filename[30])
{
	sys *dect=myfile;
    filelength=0;
	while(myfile)
	{
		if ((strcmp(myfile->name,filename)==0)&&(myfile->i>1)&&(strcmp(myfile->dect,current)==0))
		{
			filelength=filelength+strlen(myfile->memo);
		}
		myfile=myfile->next ;
	}
}
//创建新文件------------------------------------
Files* create()
{
	int n=0;
	Files *ps;        //临时节点
	Files *pend;      //最后一个i节点
	ps=new Files; 
	ps->num=0; 
	strcpy(ps->name,"..");    
	file=NULL;
	pend=ps;    
	while(n!=1)
	{
		n=n+1;
		if (file==NULL)
			file=ps;
		else
			pend->next =ps;  
		pend=ps;
		ps=new Files;
		ps->num =1;
		strcpy(ps->name ,"..");  
    } 
	pend->next=NULL;
	delete ps;
	return(file); 
}
//读文件------------------------------------
void read(sys *myfile,char filename[30])
{
	sys *dect=myfile;
    filelength=0;
	while(myfile)
	{
		if ((strcmp(myfile->name,filename)==0)&&(myfile->i>1)&&(strcmp(myfile->dect,current)==0))
		{
			cout<<myfile->memo<<endl;
			filelength=filelength+strlen(myfile->memo);
		}
		myfile=myfile->next ;
	}
	cout<<endl<<endl;
}
//写文件------------------------------------
void write(struct sys *myfile,struct sys *wrfile)
{
	if (myfile==NULL)
	{
		myfile=wrfile;
		wrfile->next=NULL;
		return;
	} 
	if (myfile->i >wrfile->i )
	{
		wrfile->next =myfile;
		myfile=wrfile;
		return;
	} 
	struct sys *p=myfile;
	while(p->next)
	{
		p=p->next ;
    } 
	p->next=wrfile;
	wrfile->next =NULL; 
}
//查找文件------------------------------------
int searchFile(sys *myfile,char filename[30])
{
	while(myfile)
	{
		if (strcmp(myfile->name,filename)==0)
		{
			return 1;
		}
		myfile=myfile->next ;
	}
	return 0;
}
//显示===================================================================
void display(Files *file)
{
	int fno=0;
	int dno=0;
	int fcount=0;
    Files *dect=file; 
	cout<<endl;
	while(file)
	{
		if (file->num!=0)
		{            
			if (file->p==0&&strcmp(file->fadect,predect)==0)
			{   
				getlen(myfile,file->name);
				cout<<setiosflags(ios::left)<<setw(12)<<file->name<<setiosflags(ios::left)<<setw(20)<<":File"<<endl;  
				fcount=fcount+filelength;
				fno=fno+1;   
			}   
		}
		file=file->next;  
	}
	while(dect)
	{
		if ((dect->num!=0)&&(strcmp(dect->fadect,predect)==0))
		{
			if (dect->p==1)
			{
				cout<<setiosflags(ios::left)<<setw(12)<<dect->name<<setiosflags(ios::left)<<setw(20)<<":DIR"<<endl;
				dno=dno+1;
			}   
		}
		dect=dect->next;  
	}
	int free;
	free =32256 - used;
	cout<<endl;
	cout<<setiosflags(ios::left)<<setw(25)<<"File Number:"<<setiosflags(ios::left)<<setw(20)<<fno
		<<used<<" bytes"<<endl;
	cout<<setiosflags(ios::left)<<setw(25)<<"Directorie Number:"<<setiosflags(ios::left)<<setw(20)<<dno
		<<free<<" bytes free"<<endl;
}
//加入文件节点------------------------------------
void insert( Files *file, Files *newfile)
{
	if (file==NULL)
	{
		file=newfile;
		newfile->next=NULL;
		return;
	} 
	if (file->num > newfile->num )
	{
		newfile->next =file;
		file=newfile;
		return;
	} 
	Files *p=file;
	while(p->next)
	{
		p=p->next ;
    } 
	p->next=newfile;
	newfile->next =NULL;
}
//删除文件------------------------------------
void deletef(Files *file,char name[20])
{
	Files *p;
	if(!file)
	{
		cout<<"ERROR: can not delete a dectory!  "<<endl<<endl;return;
	}
	if (strcmp(file->name,name)==0)
	{
		if (file->p ==0)
		{
			p=file;
			file=file->next ;
			used -= file->length;
			cout<<endl;
			delete p;
			return;
		}
	} 
	for(Files *pg=file;pg->next ;pg=pg->next )
	{
		if (strcmp(pg->next->name ,name)==0)
		{
			used -= pg->next->length;
			if (pg->next->p ==0)
			{
				p=pg->next ;
				pg->next =p->next ;    
				
				cout<<endl;
				delete p;
				return;
			}
		}
	}
	cout<<"ERROR: file not found. "<<endl<<endl;
}
//改变目录------------------------------------
void cd(Files *file,char dect[20])
{
	while(file)
	{
		if((strcmp(file->name,dect)==0)&&(file->p==1))
		{
			strcpy(predect,current);
			strcpy(current,dect);
			strcat(nowdir, dect);
			strcat(nowdir, "/");
			return;
		}  
		file=file->next ;
	}
}

//入口函数main()
int main()
{   
	char username[20];  
    char password[20]; 
	Files *addfile;

	//初始界面
    cout<<"******************************************************************"<<endl;
    cout<<"*                  欢迎使用模拟UNIX文件系统                      *"<<endl;
    cout<<"*                                                                *"<<endl; 
    cout<<"*                                                                *"<<endl;
    cout<<"*             用户名:user1/user2        密码:123/456             *"<<endl;
    cout<<"******************************************************************"<<endl<<endl;  

	//输入用户名和密码
    while(true)
	{
        cout<<"用户名: ";
        cin>>username;
        cout<<"密码  : ";
        cin>>password;    
        if(checkUser(username, password))
		{
            break; 
		}
        else
		{
            cout<<"用户名或密码错误,请重新输入!"<<endl;
		}
	}

    cout<<endl<<"登陆成功,欢迎使用模拟UNIX文件系统!(使用help命令查看帮助信息)"<<endl<<endl;
    file=create(); 
    myfile=createFile();    
    strcpy(current,"/");
    strcpy(predect,"..");
    strcpy(nowdir,"/");
    used =0;
begin:
    char command[10];
    cout<<"["<<username<<"]: "<<nowdir<<">";
    cin>>command;

    //列出文件和目录:dir
    if (strcmp(command,"dir")==0)
	{
        display(file);
        goto begin;
	} 
	
    //打开文件:open
    if (strcmp(command,"open")==0)
	{
        char filename[30];
        cin>>filename;
        int r=searchFile(myfile,filename);
        if(r==1)
		{
            read(myfile,filename);
		}
        else
		{
            cout<<"No such file!"<<endl;
		}
		
        goto begin;
	}
	
    //查看帮助信息:help
    if (strcmp(command,"help")==0)
	{
        help();
        goto begin;
	}
	
    //删除文件:delete
    if (strcmp(command,"delete")==0)
	{
        char delname[20];
		cout<<"请输入要删除的目录名或者文件名:";
        cin>>delname;
        deletef(file,delname);
		
        goto begin;
	}

    //改变目录:cd
    char dect[20];
    if (strcmp(command,"cd")==0)
	{
        cin>>dect;
        if (strcmp(dect,"/")==0)
		{
            strcpy(current,"/");
            strcpy(predect,"..");
            strcpy(nowdir,"/");
            goto begin;
		}
        else
		{
            cd(file,dect);
            goto begin;
		}
	}
	
    //新建目录:mkdir
    if (strcmp(command,"mkdir")==0)
	{
        no=no+1;  
        addfile=new Files;
        addfile->num =no;  
        cin>>addfile->name;
        addfile->p =1;
        addfile->length =strlen(addfile->name);    
        strcpy(addfile->fadect,predect);
        insert(file,addfile);  
        cout<<"Make Directory Successful!"<<endl;
        goto begin;
	}
	
	//创建文件:create
	if (strcmp(command,"create")==0)
	{ 
		fnode=fnode+1;
		sys *alterfile;
		alterfile=new sys;
		alterfile->i =fnode;
		cout<<"请输入文件名:";
		cin>>alterfile->name ;  
		int r;
		r=searchFile(myfile,alterfile->name);
		if (r!=1)
		{
			no=no+1;
			addfile=new Files;
			char filen[30];
			addfile->num =no;
			strcpy(addfile->mode,"rw-r-");
			strcpy(addfile->name ,alterfile->name); 
			strcpy(filen,addfile->name);
			addfile->p =0;
			addfile->length =0;
			strcpy(addfile->fadect,predect);
			sys *appfile;
			appfile=new sys;
			fnode=fnode+1;                   
			appfile->i =fnode;
			strcpy(appfile->name,addfile->name);
			strcpy(appfile->dect,current);
			cout<<"请输入文件大小:";
			cin>>appfile->memo ;
			write(myfile,appfile);
			addfile->length =strlen(appfile->memo);
			used += addfile->length;
			insert(file,addfile);
			goto begin;
		}
		cin>>alterfile->memo ;
		used += strlen(alterfile->memo);
        strcpy(alterfile->dect,current);
        write(myfile,alterfile);
		cout<<"File Successful!"<<endl;
		goto begin;
	}
	
	//退出系统:logout
	if (strcmp(command,"logout")==0)
	{
		return;  
	}
	cout<<"找不到这个命令,请输入help查看帮助信息!"<<endl<<endl;
	goto begin;
    return;
}