C语言文件系统设计

  文件系统设计
1．文件系统
①下列几条命令
LOGIN    用户登陆
DIR       列文件目录
CREATE   创建文件
DELETE   删除文件
OPEN     打开文件
CLOSE    关闭文件
READ     读文件
WRITE    写文件
②列目录时要列出文件名，物理地址，保护码和文件长度。
③源文件可以进行读写保护。
①首先应确定文件系统的数据结构：主目录、子目录及活动文件等。主目录和子目录都以文件的形式存放于磁盘，这样便于查找和修改。
②用户创建的文件，可以编号存储于磁盘上。如：file0,file1,file2…并以编号作为物理地址，在目录中进行登记。
程序见下（本程序需要在c:下建一个名为osfile的目录及一个名为file的子目录）：
#include "stdio.h"
#include "string.h"
#include "conio.h"
#include "stdlib.h"
#define MAXNAME 25  /*the largest length of mfdname,ufdname,filename*/
#define MAXCHILD 50 /*the largest child*/
#define MAX (MAXCHILD*MAXCHILD) /*the size of fpaddrno*/ [资料来源：http://think58.com]

typedef struct  /*the structure of OSFILE*/
  {int  fpaddr;                /*file physical address*/
   int  flength;               /*file length*/
   int  fmode;   /*file mode:0-Read Only;1-Write Only;2-Read and Write(default);*/
   char fname[MAXNAME];        /*file name*/
  } OSFILE; copyright think58 [资料来源：THINK58.com]

typedef struct     /*the structure of OSUFD*/
  {char ufdname[MAXNAME];   /*ufd name*/
   OSFILE ufdfile[MAXCHILD];   /*ufd own file*/
  }OSUFD;

think58好，好think58 [资料来源：www.THINK58.com]

typedef struct  /*the structure of OSUFD'LOGIN*/
  {char ufdname[MAXNAME];       /*ufd name*/
   char ufdpword[8];            /*ufd password*/
  } OSUFD_LOGIN;

think58好，好think58 [来源：http://think58.com]

[资料来源：http://think58.com]

typedef struct     /*file open mode*/
  {int ifopen;     /*ifopen:0-close,1-open*/
   int openmode;   /*0-read only,1-write only,2-read and write,3-initial*/
  }OSUFD_OPENMODE;

think58好，好think58

[来源：http://www.think58.com]

OSUFD *ufd[MAXCHILD];   /*ufd and ufd own files*/
OSUFD_LOGIN ufd_lp;

think58 [资料来源：http://www.THINK58.com]

[来源：http://think58.com]

int ucount=0;  /*the count of mfd's ufds*/
int fcount[MAXCHILD];  /*the count of ufd's files*/
int loginsuc=0; /*whether login successfully*/
char username[MAXNAME];  /*record login user's name22*/
char dirname[MAXNAME];/*record current directory*/
int fpaddrno[MAX];  /*record file physical address num*/
OSUFD_OPENMODE ifopen[MAXCHILD][MAXCHILD]; /*record file open/close*/
int wgetchar; /*whether getchar()*/ [资料来源：http://think58.com]

FILE *fp_mfd,*fp_ufd,*fp_file_p,*fp_file; copyright think58

void main()
{int i,j,choice1;
 char choice[50];  /*choice operation:dir,create,delete,open,delete,modify,read,write*/
 int choiceend=1;  /*whether choice end*/
 char *rtrim(char *str);  /*remove the trailing blanks.*/
 char *ltrim(char *str);  /*remove the heading blanks.*/
 void LoginF();  /*LOGIN FileSystem*/
 void DirF();  /*Dir FileSystem*/
 void CdF();  /*Change Dir*/
 void CreateF();  /*Create File*/
 void DeleteF(); /*Delete File*/
 void ModifyFM(); /*Modify FileMode*/
 void OpenF();  /*Open File*/
 void CloseF();  /*Close File*/
 void ReadF(); /*Read File*/
 void WriteF(); /*Write File*/
 void QuitF(); /*Quit FileSystem*/
 void help();
 if((fp_mfd=fopen("c:\\osfile\\mfd","rb"))==NULL)
   {fp_mfd=fopen("c:\\osfile\\mfd","wb");
 fclose(fp_mfd);
   } think58好，好think58 [资料来源：http://www.THINK58.com]

 for(i=0;i<MAX;i++) fpaddrno[i]=0;
 textattr(BLACK*16|WHITE);
 clrscr();   /*clear screen*/
 LoginF();   /*user login*/
 clrscr();

[资料来源：http://think58.com]

 if(loginsuc==1)  /*Login Successfully*/
 {while (1)
 {wgetchar=0;
  if (choiceend==1)
  {printf("\n\nC:\\%s>",strupr(dirname));}
  else printf("Bad command or file name.\nC:\\%s>",strupr(username));
   gets(choice);
   strcpy(choice,ltrim(rtrim(strlwr(choice))));
   if (strcmp(choice,"dir")==0) choice1=1;
   else if(strcmp(choice,"creat")==0) choice1=2;
   else if(strcmp(choice,"delete")==0) choice1=3;
   else if(strcmp(choice,"attrib")==0) choice1=4;
   else if(strcmp(choice,"open")==0) choice1=5;
   else if(strcmp(choice,"close")==0) choice1=6;
   else if(strcmp(choice,"read")==0) choice1=7;
   else if(strcmp(choice,"modify")==0) choice1=8;
   else if(strcmp(choice,"exit")==0) choice1=9;
   else if(strcmp(choice,"cls")==0) choice1=10;
   else if(strcmp(choice,"cd")==0) choice1=11; think58好，好think58

   else if(strcmp(choice,"help")==0) choice1=20;
   else choice1=12;
  switch(choice1)
    {case 1:DirF();choiceend=1;break;
 case 2:CreateF();choiceend=1;if(!wgetchar) getchar();break;
 case 3:DeleteF();choiceend=1;if(!wgetchar)getchar();break;
 case 4:ModifyFM();choiceend=1;if(!wgetchar) getchar();break;
 case 5:choiceend=1;OpenF();if (!wgetchar) getchar();break;
 case 6:choiceend=1;CloseF();if (!wgetchar) getchar();break;
 case 7:choiceend=1;ReadF();if (!wgetchar) getchar();break;
 case 8:choiceend=1;WriteF();if (!wgetchar) getchar();break;
 case 9:printf("\nYou have exited this system.");
     QuitF();exit(0);break;
 case 10:choiceend=1;clrscr();break;
 case 11:CdF();choiceend=1;break;
 case 20:help();choiceend=1;break;
 default:choiceend=0;
    }
   }
}
else printf("\nAccess denied.");
}

copyright think58 [资料来源：THINK58.com]

void help(void)
{
printf("\nThe Command List\n");
printf("\nCd  Attrib  Creat  Modify  Read  Open  Cls  Delete  Exit  Close\n");
}
char *rtrim(char *str)  /*remove the trailing blanks.*/
{int n=strlen(str)-1;
 while(n>=0)
 {if(*(str+n)!=' ')
   {*(str+n+1)='\0';
 break;
   }
   else n--;
 }
 if (n<0) str[0]='\0';
 return str;
} copyright think58

[资料来源：www.THINK58.com]

char *ltrim(char *str) /*remove the heading blanks.*/
{char *rtrim(char *str);
 strrev(str);
 rtrim(str);
 strrev(str);
 return str;
} think58.com [资料来源：www.THINK58.com]

void LoginF()  /*LOGIN FileSystem*/
{char loginame[MAXNAME],loginpw[9],logincpw[9],str[50];
 int i,j,flag=1;
 char a[25];
 int findout; /*login user not exist*/
 char *rtrim(char *str);  /*remove the trailing blanks.*/
 char *ltrim(char *str);  /*remove the heading blanks.*/
 void InputPW(char *password);  /*input password,use '*' replace*/
 void SetPANo(int RorW);  /*Set physical address num*/
 while(1)
 {findout=0;
 printf("\n\nLogin Name:");
 gets(loginame);
 ltrim(rtrim(loginame));
 fp_mfd=fopen("c:\\osfile\\","rb");
 for(i=0;fread(&ufd_lp,sizeof(OSUFD_LOGIN),1,fp_mfd)!=0;i++)
  if (strcmp(strupr(ufd_lp.ufdname),strupr(loginame))==0)
 {findout=1;
  strcpy(logincpw,ufd_lp.ufdpword);
 }
 fclose(fp_mfd);
 if (findout==1)  /*user exist*/
 {printf("Login Password:");
  InputPW(loginpw); /*input password,use '*' replace*/ think58.com

   if (strcmp(loginpw,logincpw)==0)
  {strcpy(username,strupr(loginame));
   strcpy(dirname,username);
   fp_mfd=fopen("c:\\osfile\\","rb");
   for(j=0;fread(&ufd_lp,sizeof(OSUFD_LOGIN),1,fp_mfd)!=0;j++)
  {strcpy(str,"c:\\osfile\\");
   strcat(str,ufd_lp.ufdname);
   ufd[j]=(OSUFD*)malloc(sizeof(OSUFD));
   strcpy(ufd[j]->ufdname,strupr(ufd_lp.ufdname));
   fp_ufd=fopen(str,"rb");
   fcount[j]=0;
   for(i=0;fread(&ufd[j]->ufdfile[i],sizeof(OSFILE),1,fp_ufd)!=0;i++,fcount[j]++)
     {ifopen[j][i].ifopen=0;
     ifopen[j][i].openmode=4;}
   fclose(fp_ufd);}
   fclose(fp_mfd);
   ucount=j;
   SetPANo(0);
  printf("\n\nLogin successful! Welcome to this FileSystem\n\n");
  loginsuc=1;
  return;}
   else
  {printf("\n\n"); copyright think58
   flag=1;
   while(flag)
   {printf("Login Failed!  Password Error.  Try Again(Y/N):");
   gets(a);
   ltrim(rtrim(a));
   if (strcmp(strupr(a),"Y")==0) {loginsuc=0;flag=0;}
   else if(strcmp(strupr(a),"N")==0){loginsuc=0;flag=0;return;}
   }
  }
   }
 else
   {printf("New Password(<=8):");
    InputPW(loginpw); /*input new password,use '*' replace*/
    printf("\nConfirm Password(<=8):"); /*input new password,use '*' replace*/
    InputPW(logincpw);
   if (strcmp(loginpw,logincpw)==0)
  {strcpy(ufd_lp.ufdname,strupr(loginame));
   strcpy(ufd_lp.ufdpword,loginpw);
   fp_mfd=fopen("c:\\osfile\\","ab");
   fwrite(&ufd_lp,sizeof(OSUFD_LOGIN),1,fp_mfd);
   fclose(fp_mfd);
   strcpy(username,strupr(loginame));
   strcpy(dirname,loginame);
   strcpy(str,"c:\\osfile\\");
   strcat(str,username);
   if((fp_ufd=fopen(str,"rb"))==NULL)
  {fp_ufd=fopen(str,"wb");
   fclose(fp_ufd);
  }
   fp_mfd=fopen("c:\\osfile\\","rb");
   for(j=0;fread(&ufd_lp,sizeof(OSUFD_LOGIN),1,fp_mfd)!=0;j++)
  {strcpy(str,"c:\\osfile\\");
   strcat(str,ufd_lp.ufdname);
   ufd[j]=(OSUFD*)malloc(sizeof(OSUFD));
   strcpy(ufd[j]->ufdname,strupr(ufd_lp.ufdname));
   fp_ufd=fopen(str,"rb");
   for(i=0;fread(&ufd[j]->ufdfile[i],sizeof(OSFILE),1,fp_ufd)!=0;i++,fcount[j]++)
     {ifopen[j][i].ifopen=0;
     ifopen[j][i].openmode=4;}
   fclose(fp_ufd);}
   fclose(fp_mfd);
   ucount=j;
   SetPANo(0);
   printf("\n\nLogin Successful! Welcome to this System\n\n");
   loginsuc=1; think58 [来源：http://think58.com]
   return;
   }
   else
   {printf("\n\n");
   flag=1;
   while(flag)
   {printf("Login Failed! Password Error. Try Again(Y/N):");
   gets(a);
   ltrim(rtrim(a));
   if (strcmp(strupr(a),"Y")==0) {loginsuc=0;flag=0;}
   else if(strcmp(strupr(a),"N")==0){loginsuc=0;flag=0;return;}
   }
   }
 }
 }
 } think58.com [资料来源：www.THINK58.com]

void SetPANo(int RorW)  /*Set physical address num,0-read,1-write*/
{int i,j;
 if (RorW==0)
 {if((fp_file_p=fopen("c:\\osfile\\file\\file_p","rb"))==NULL)
     {fp_file_p=fopen("c:\\osfile\\file\\file_p","wb");
      fclose(fp_file_p);
     }
  fp_file_p=fopen("c:\\osfile\\file\\file_p","rb");
  for(i=0;fread(&j,sizeof(int),1,fp_file_p)!=0;i++)
    fpaddrno[j]=1;
  /*for(i=1;i<MAX;i++)
    if ((i%13)==0) fpaddrno[i]=1;*/
 }
 else
 {fp_file_p=fopen("c:\\osfile\\file\\file_p","wb");
  /*for(i=1;i<MAX;i++)
    if((i%13)==0) fpaddrno[i]=0;*/
  for(i=0;i<MAX;i++)
  if (fpaddrno[i]==1)
  fwrite(&i,sizeof(int),1,fp_file_p);
  }
 fclose(fp_file_p);
} [来源：http://think58.com]

void InputPW(char *password)  /*input password,use '*' replace*/
{int j;
内容来自think58 [资料来源：http://www.THINK58.com]