windows fat16文件系统模拟

#include <stdio.h> #include <time.h> #include <stdlib.h> #include <string.h> #include "fat16.h" //位图 unsigned __int8 bitMap[BIT_MAP_ROW][BIT_MAP_COL]; //读写缓存，这里取一个簇的大小 unsigned __int8 rwBuffer[BUFFER_SIZE]; //当前工作目录 char curWorkDir[PATH_LEN]; //根目录的FCB struct FCB rootFCB; //当前文件夹的FCB struct FCB curFCB; //fat表 unsigned __int16 fatTable[CLUSTER_NUM]; //硬盘文件的句柄 FILE *disk; //打开文件的句柄 struct fileHANDLE fHandle[MAX_FILE_OPEN]; void fatFormat() { disk = fopen("fat16.disk","wb+"); struct FCB root; int i,j,k; k = 0; printf("开始硬盘格式化......\n"); //初始化缓存 for(i = 0;i < BUFFER_SIZE;i++) { rwBuffer[i] = '0'; } //初始化fat表 for(i = 0;i < CLUSTER_NUM;i++) { fatTable[i] = 0; } //初始化bitMap表,置为1表示未使用，置为为0表示使用 for(i = 0;i < BIT_MAP_ROW;i++) for(j = 0;j < BIT_MAP_COL;j++) { if(k <= DATE_START) { bitMap[i][j]=0; } else { bitMap[i][j]=1; } k++; } //初始化硬盘 for(i = 0;i < CLUSTER_NUM;i++) { fwrite(rwBuffer,sizeof(__int8),BUFFER_SIZE,disk); } //写fat表，占256块，编号为0-255，大小为128kB /* fseek(disk,0,SEEK_SET); fwrite(fatTable,sizeof(__int16),CLUSTER_NUM,disk); //写bitmap表，占16*8块，编号为256-383，大小为64kB fseek(disk,256*BLOCK_SIZE,SEEK_SET); for(i = 0;i < BIT_MAP_ROW;i++) { fwrite(bitMap[i],sizeof(__int8),BIT_MAP_COL,disk); } */ //写分区信息占用物理块号为399块，即根FCB的信息,这里应该使用的是编号为400的块 fseek(disk,VOLUM_START*BLOCK_SIZE,SEEK_SET); root.block_no = DATE_START; root.block_num = 1; root.create_time = time(NULL); root.file_size = 2; root.file_type = DIR_TYPE; strcpy(root.filename,"C:"); root.last_modify = time(NULL); //writeFCB(&root); fwrite(&root,sizeof(struct FCB),1,disk); //文件指针定位到下一块，这里是根目录的内容 fseek(disk,DATE_START*BLOCK_SIZE,SEEK_SET); //写两个文件目录.和.. strcpy(root.filename,"."); //writeFCB(&root); fwrite(&root,sizeof(struct FCB),1,disk); strcpy(root.filename,".."); //writeFCB(&root); fwrite(&root,sizeof(struct FCB),1,disk); /*strcpy(root.filename,"program"); root.block_no = mallocBlock(); root.file_size = 4; fwrite(&root,sizeof(struct FCB),1,disk); fseek(disk,root.block_no*BLOCK_SIZE,SEEK_SET); strcpy(root.filename,"."); //writeFCB(&root); fwrite(&root,sizeof(struct FCB),1,disk); strcpy(root.filename,".."); fwrite(&root,sizeof(struct FCB),1,disk); root.block_no = mallocBlock(); root.block_num = 1; root.file_size = 0; root.file_type = FILE_TYPE; strcpy(root.filename,"test.txt"); fwrite(&root,sizeof(struct FCB),1,disk); root.block_no =mallocBlock(); strcpy(root.filename,"youjingdi.txt"); fwrite(&root,sizeof(struct FCB),1,disk); */ fseek(disk,0,SEEK_SET); fwrite(fatTable,sizeof(__int16),CLUSTER_NUM,disk); //写bitmap表，占16*8块，编号为256-383，大小为64kB for(i = 0;i < BIT_MAP_ROW;i++) { fwrite(bitMap[i],sizeof(__int8),BIT_MAP_COL,disk); } printf("格式化完毕\n"); fclose(disk); fatInit(); } void fatInit() { int i; disk = fopen("fat16.disk","rb+"); if(disk==NULL) { printf("format the disk?[y/n]:"); i = getchar(); if(i=='y'|| i=='Y') fatFormat(); else { exit(0); } } disk = fopen("fat16.disk","rb+"); fseek(disk,0,SEEK_SET); fread(fatTable,sizeof(__int16),CLUSTER_NUM,disk); //写bitmap表，占16*8块，编号为256-383，大小为64kB fseek(disk,256*BLOCK_SIZE,SEEK_SET); for(i = 0;i < BIT_MAP_ROW;i++) { fread(bitMap[i],sizeof(__int8),BIT_MAP_COL,disk); } for(i = 0;i < MAX_FILE_OPEN;i++) { fHandle[i].cur_point = 0; fHandle[i].file_fcb.block_no = 0; fHandle[i].file_fcb.block_num = 0; fHandle[i].file_fcb.create_time = 0; fHandle[i].file_fcb.file_size = 0; fHandle[i].file_fcb.file_type = 0; strcpy(fHandle[i].file_fcb.filename,""); fHandle[i].file_fcb.last_modify = 0; fHandle[i].handle = -1; } fseek(disk,VOLUM_START*BLOCK_SIZE,SEEK_SET); fread(&rootFCB,sizeof(struct FCB),1,disk); //printf("%d\n",rootFCB.file_size); memcpy(&curFCB,&rootFCB,sizeof(struct FCB)); strcpy(curWorkDir,"C:"); } int fatCreate(char *fileName) { struct FCB tmpFCB; struct FCB fileFCB; struct FCB backup_curfcb; char backup_curdir[PATH_LEN+1]; char backup_fileName[NAME_LEN+1]; int i,j,k; int size,blockNum,blockNo; memcpy(&tmpFCB,&curFCB,sizeof(struct FCB)); blockNo = tmpFCB.block_no; blockNum = tmpFCB.block_num; size = tmpFCB.file_size; fseek(disk,blockNo*BLOCK_SIZE,SEEK_SET); for(i = 0;i < size;i++) { if(i!=0 && i%16==0) { blockNo = fatTable[blockNo]; fseek(disk,blockNo*BLOCK_SIZE,SEEK_SET); } fread(&tmpFCB,sizeof(struct FCB),1,disk); if(strcmp(tmpFCB.filename,fileName)==0) { printf("the name is used\n"); return -1; } } memcpy(&tmpFCB,&curFCB,sizeof(struct FCB)); blockNo = tmpFCB.block_no; blockNum = tmpFCB.block_num; size = tmpFCB.file_size; //跳转到最后一块 for(i = 0;i < blockNum -1;i++) { blockNo = fatTable[blockNo]; } size=size%16; if(size==0) { //当前块已经满了，需要申请新的物理块 fatTable[blockNo] = mallocBlock(); //切换到当前工作块上 blockNo = fatTable[blockNo]; tmpFCB.block_num++; } tmpFCB.file_size++; fseek(disk,blockNo*BLOCK_SIZE+size*(sizeof(struct FCB)),SEEK_SET); fileFCB.block_no = mallocBlock(); fileFCB.block_num = 1; fileFCB.create_time = time(NULL); fileFCB.file_size = 0; fileFCB.file_type = FILE_TYPE; strcpy(fileFCB.filename,fileName); fileFCB.last_modify = time(NULL); fwrite(&fileFCB,sizeof(struct FCB),1,disk); //已经是根目录了。则直接修改根FCB即可 if(strcmp(curWorkDir,"C:")==0) { fseek(disk,VOLUM_START*BLOCK_SIZE,SEEK_SET); fwrite(&tmpFCB,sizeof(struct FCB),1,disk); memcpy(&rootFCB,&tmpFCB,sizeof(struct FCB)); memcpy(&curFCB,&tmpFCB,sizeof(struct FCB)); } //否则跳到上一级目录 else { //备份当前工作目录和当前的FCB strcpy(backup_curdir,curWorkDir); memcpy(&backup_curfcb,&tmpFCB,sizeof(struct FCB)); getLastName(backup_curdir,backup_fileName); //切换到上一级目录，来修改其当前文件夹的FCB内容 cd(".."); blockNo = curFCB.block_no; size = curFCB.file_size; fseek(disk,blockNo*BLOCK_SIZE,SEEK_SET); for(i = 0;i < size;i++) { fread(&tmpFCB,sizeof(struct FCB),1,disk); { if(strcmp(tmpFCB.filename,backup_fileName)==0 && tmpFCB.file_type == DIR_TYPE) { printf("yes find \n"); break; } } } fseek(disk,0-sizeof(struct FCB),SEEK_CUR); fwrite(&backup_curfcb,sizeof(struct FCB),1,disk); //还原当前工作目录和当前的FCB strcpy(curWorkDir,backup_curdir); memcpy(&curFCB,&backup_curfcb,sizeof(struct FCB)); } fflush(disk); return 0; } int fatRename(char *srcName,char *dirName) { struct FCB tmpFCB; struct FCB backup_curfcb; int size,node,num,i; int flag = 0; memcpy(&tmpFCB,&curFCB,sizeof(struct FCB)); node = tmpFCB.block_no; num = tmpFCB.block_num; size = tmpFCB.file_size; fseek(disk,node*BLOCK_SIZE,SEEK_SET); for(i = 0;i < size;i++) { if(i!=0 && i%16==0) { node = fatTable[node]; fseek(disk,node*BLOCK_SIZE,SEEK_SET); } fread(&tmpFCB,sizeof(struct FCB),1,disk); if(strcmp(tmpFCB.filename,dirName)==0) { printf("the name is used\n"); return -1; } } memcpy(&tmpFCB,&curFCB,sizeof(struct FCB)); size = tmpFCB.file_size; node = tmpFCB.block_no; fseek(disk,(node)*BLOCK_SIZE,SEEK_SET); for(i = 0; i < size;i++) { if(i!=0 && i%16==0) { node = fatTable[node]; fseek(disk,(node)*BLOCK_SIZE,SEEK_SET); } fread(&tmpFCB,sizeof(struct FCB),1,disk); if(strcmp(tmpFCB.filename,srcName)==0) { flag = 1; break; } } if(flag==1) { strcpy(tmpFCB.filename,dirName); fseek(disk,0-sizeof(struct FCB),SEEK_CUR); fwrite(&tmpFCB,sizeof(struct FCB),1,disk); } else { prin