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1、操作系统文件操作实验四 文件操作 一、实验名称：简单文件系统的实现 二、实验目的要求 在TC、VB、Delphi、C+Builder等语言与开发环境中，实现对文件的各项操作；使学生进一步了解文件的主要操作。 三、实验内容 为DOS系统设计一个简单的二级文件系统。要求做到以下几点： 可以实现下列几条命令 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 MODIFY 修改文件内容 列目录时要列出文件名，物理地址，保护码和文件长度。 源文件可以进行读写保护。 四、实验提示 首先应
2、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。 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。 五、实验运行结果 参考程序见下: #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 l
3、argest child*/ #define MAX (MAXCHILD*MAXCHILD) /*the size of fpaddrno*/ 1 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 fnameMAXNAME; /*file name*/ OSFILE
4、; typedef struct /*the structure of OSUFD*/ char ufdnameMAXNAME; /*ufd name*/ OSFILE ufdfileMAXCHILD; /*ufd own file*/ OSUFD; typedef struct /*the structure of OSUFDLOGIN*/ char ufdnameMAXNAME; /*ufd name*/ char ufdpword8; /*ufd password*/ OSUFD_LOGIN; typedef struct /*file open mode*/ int ifopen; /
5、*ifopen:0-close,1-open*/ int openmode; /*0-read only,1-write only,2-read and write,3-initial*/ OSUFD_OPENMODE; OSUFD *ufdMAXCHILD; /*ufd and ufd own files*/ OSUFD_LOGIN ufd_lp; int ucount=0; /*the count of mfds ufds*/ int fcountMAXCHILD; /*the count of ufds files*/ int loginsuc=0; /*whether login su
6、ccessfully*/ char usernameMAXNAME; /*record login users name22*/ char dirnameMAXNAME;/*record current directory*/ int fpaddrnoMAX; /*record file physical address num*/ OSUFD_OPENMODE ifopenMAXCHILDMAXCHILD; /*record file open/close*/ int wgetchar; /*whether getchar*/ FILE *fp_mfd,*fp_ufd,*fp_file_p,
7、*fp_file; void main int i,j,choice1; char choice50; /*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.*/ 2 void LoginF; /*LOGIN FileS
8、ystem*/ 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*/ vo
9、id help; if(fp_mfd=fopen(c:osfilemfd,rb)=NULL) fp_mfd=fopen(c:osfilemfd,wb); for(i=0;i,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;
10、 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
11、; else if(strcmp(choice,cls)=0) choice1=10; else if(strcmp(choice,cd)=0) choice1=11; else if(strcmp(choice,help)=0) choice1=20; else choice1=12; fclose(fp_mfd); 3 switch(choice1) case 1:DirF;choiceend=1;break; case 2:CreateF;choiceend=1;if(!wgetchar) getchar;break; case 3:DeleteF;choiceend=1;if(!wge
12、tchar)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;
13、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.); void help(void) printf(nThe Command Listn); printf(nCd Attrib Creat Modify Read Open
14、Cls Delete Exit Closen); 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 (nufdname,strupr(ufd_lp.ufdname); fp_ufd=fopen(str,rb); fcountj=0; ifopenji.ifopen=0; ifopenji.openmode=4; fclose(fp_ufd); for(i=0;fread(&u
15、fdj-ufdfilei,sizeof(OSFILE),1,fp_ufd)!=0;i+,fcountj+) fclose(fp_mfd); 5 ucount=j; SetPANo(0); printf(nnLogin successful! Welcome to this FileSystemnn); loginsuc=1; return; else printf(nn); flag=1; while(flag) printf(Login Failed! Password Error. Try Again(Y/N):); gets(a); ltrim(rtrim(a); if (strcmp(
16、strupr(a),Y)=0) loginsuc=0;flag=0; else if(strcmp(strupr(a),N)=0)loginsuc=0;flag=0;return; printf(New Password(=8):); InputPW(loginpw); /*input new password,use * replace*/ printf(nConfirm Password(ufdname,strupr(ufd_lp.ufdname); fp_ufd=fopen(str,rb); 6 for(i=0;fread(&ufdj-ufdfilei,sizeof(OSFILE),1,
17、fp_ufd)!=0;i+,fcountj+) void SetPANo(int RorW) /*Set physical address num,0-read,1-write*/ int i,j; if (RorW=0) if(fp_file_p=fopen(c:osfilefilefile_p,rb)=NULL) fp_file_p=fopen(c:osfilefilefile_p,wb); fclose(fp_file_p); fp_file_p=fopen(c:osfilefilefile_p,rb); for(i=0;fread(&j,sizeof(int),1,fp_file_p)
18、!=0;i+) fpaddrnoj=1; /*for(i=1;iMAX;i+) if (i%13)=0) fpaddrnoi=1;*/ fp_file_p=fopen(c:osfilefilefile_p,wb); /*for(i=1;iMAX;i+) if(i%13)=0) fpaddrnoi=0;*/ for(i=0;iMAX;i+) ifopenji.ifopen=0; ifopenji.openmode=4; fclose(fp_ufd); fclose(fp_mfd); ucount=j; SetPANo(0); printf(nnLogin Successful! Welcome
19、to this Systemnn); loginsuc=1; return; else printf(nn); 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 7 if (fpaddrnoi=1) fwrite(&i,sizeof(i
20、nt),1,fp_file_p); fclose(fp_file_p); void InputPW(char *password) /*input password,use * replace*/ int j; for(j=0;jdirn,dirname); printf(n%14s%16s%14s%10s%18sn,FileName,FileAddress,FileLength,Type,FileMode); j=ExistD(dirname); for(i=0;i0) j-;j-; putchar(b);putchar( );putchar(b); else j-; else passwo
21、rdj=0; break; passwordj=0; 8 clrscr; printf(n%14s%16s%14s%10s%18sn,FileName,FileAddress,FileLength,Type,FileMode); itoa(ufdj-ufdfilei.fpaddr,str,10); strcpy(sfpaddr,file); strcat(sfpaddr,str); if (ufdj-ufdfilei.fmode=0) strcpy(sfmode,Read Only); else if(ufdj-ufdfilei.fmode=1) strcpy(sfmode,Write Onl
22、y); else if(ufdj-ufdfilei.fmode=2)strcpy(sfmode,Read And Write); else strcpy(sfmode,Protect); printf(%14s%16s%14d%10s%18sn,ufdj-ufdfilei.fname,sfpaddr,ufdj-ufdfilei.flength,sfmode); printf(n %3d file(s)n,fcountj); else printf(nnC:dirn); printf(n%14s%18s%8sn,DirName,OwnFileCount,Type); for(i=0;iufdna
23、me,fcounti,); count=count+fcounti; printf(n %3d dir(s),%5d file(s)n,ucount,count); int ExistD(char *dirname) /*Whether DirName Exist,Exist-i,Not Exist-0*/ int i; int exist=0; for(i=0;iufdname),strupr(dirname)=0) exist=1; break; if (exist) return(i); else return(-1); 9 void CdF /*Exchange Dir*/ char
24、dnameMAXNAME; char *rtrim(char *str); /*remove the trailing blanks.*/ char *ltrim(char *str); /*remove the heading blanks.*/ int ExistD(char *filename); /*Whether FileName Exist,Exist-i,Not Exist-0*/ printf(nPlease input DirName (cd.-Previous dir; DirNAME-cd DirNAME):); gets(dname); ltrim(rtrim(dnam
25、e); if (ExistD(dname)=0) strcpy(dirname,strupr(dname); else if(strcmp(strupr(dname),CD.)=0) strcpy(ltrim(rtrim(dirname),); else printf(nError.%s does not exist.n,dname); void CreateF /*Create File*/ int fpaddrno,flag=1,i; char fnameMAXNAME,str50,str150,strtext255,a25; char fmode25; char *rtrim(char
26、*str); /*remove the trailing blanks.*/ char *ltrim(char *str); /*remove the heading blanks.*/ int FindPANo; /*find out physical address num*/ int WriteF1; /*write file*/ int ExistF(char *filename); /*Whether FileName Exist,Exist-i,Not Exist-0*/ int ExistD(char *dirname); if (strcmp(strupr(dirname),s
27、trupr(username)!=0) printf(nError. You must create file in your own dir.n);wgetchar=1; else printf(nPlease input FileName:); gets(fname); ltrim(rtrim(fname); if (ExistF(fname)=0) printf(nError. Name %s has already existed.n,fname); wgetchar=1; else printf(Please input FileMode(0-Read Only, 1-Write O
28、nly, 2-Read and Write, 3-Protect):); gets(fmode); ltrim(rtrim(fmode); if(strcmp(fmode,0)=0)|(strcmp(fmode,1)=0)|(strcmp(fmode,2)=0)|(st fpaddrno=FindPANo; rcmp(fmode,3)=0) 10 if (fpaddrno=0) i=ExistD(username); strcpy(ufdi-ufdfilefcounti.fname,fname); ufdi-ufdfilefcounti.fpaddr=fpaddrno; ufdi-ufdfil
29、efcounti.fmode=atoi(fmode); ifopenifcounti.ifopen=0; ifopenifcounti.openmode=4; strcpy(str,c:osfilefilefile); itoa(fpaddrno,str1,10); strcat(str,str1); fp_file=fopen(str,wb); fclose(fp_file); fcounti+; while(flag) printf(Input text now(Y/N):); gets(a); ltrim(rtrim(a); ufdi-ufdfilefcounti-1.flength=0
30、; if(strcmp(strupr(a),Y)=0) fp_file=fopen(str,wb+); ufdi-ufdfilefcounti-1.flength=WriteF1; flag=0; else if(strcmp(strupr(a),N)=0)flag=0;wgetchar=1; printf(n%s has been created successfully!n,fname); else printf(nFail!No Disk Space. Please format your disk.n);wgetchar=1; else printf(nError. FileModes
31、 Range is 0-3n);wgetchar=1; int ExistF(char *filename) /*Whether FileName Exist,Exist-i,Not Exist-0*/ int i,j; int exist=0; int ExistD(char *dirname); j=ExistD(dirname); for(i=0;iufdfilei.fname),strupr(filename)=0) exist=1; break; 11 if (exist) return(i); else return(-1); int FindPANo /*find out phy
32、sical address num*/ int i; for(i=0;iMAX;i+) if (fpaddrnoi=0) fpaddrnoi=1;break; if (iMAX) return(i); else return(-1); int WriteF1 /*write file*/ int length=0; char c; printf(Please input text(# stands for end):n); while(c=getchar)!=#) fprintf(fp_file,%c,c); if (c!=n) length+; fprintf(fp_file,n); fcl
33、ose(fp_file); return(length); void DeleteF /*Delete File*/ char fnameMAXNAME; char str50,str150; int i,j,k,flag=1; char a25; /*whether delete*/ char *rtrim(char *str); /*remove the trailing blanks.*/ char *ltrim(char *str); /*remove the heading blanks.*/ int ExistF(char *filename); /*Whether FileName Exist,Exist-i,Not Exist-0*/ int ExistD(char *dirname); if
