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VHD.c
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VHD.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
/*
boot addr: 10000
fat addr: 10400
root dic addr: 32000
data cluster: 36000
*/
typedef unsigned char byte;
typedef unsigned short hWord; // half word
typedef unsigned long word;
typedef struct mytime{
hWord year, mon, day, hour, min, sec;
} mTime;
typedef struct fileStruct{
char name[9];
char ext[4];
char attr;
mTime ftime;
hWord start;
word size;
} file;
FILE *fp;
word offSet;
byte buff_block[32768];
byte buff_byte;
hWord FAT[32768]; // [0][1] reserved start from [2][3]
hWord nByte = 512, nCluster; // number of bytes within a block, number of clusters on total
hWord nFAT, nBFAT; // number of FATs, number of blocks within a FAT
hWord nFile, nBlock; // number of files in root directory, number of blocks in a cluster
file* fIndex[512];
const char* const month[13] = {"", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nev", "Dec"};
void readBlock(word addr) { // addr: the address of blocks
fseek(fp, addr, SEEK_SET);
fread(buff_block, 1, nByte, fp);
}
byte readByte(word addr) { // addr: the address of a specific byte
fseek(fp, addr, SEEK_SET);
fread(&buff_byte, 1, 1, fp);
return buff_byte;
}
hWord readHWord(word offset) {
return (readByte(offset + 1) << 8) + readByte(offset);
}
word readWord(word offset) {
return (readHWord(offset + 2) << 16) + readHWord(offset);
}
void readFAT() {
hWord i;
for (i = 0; i < nCluster; i++) {
FAT[i] = readHWord(offSet + i * 2);
}
}
int readFileName(hWord n) {
int i;
byte head = readByte(offSet + n * 32);
if ((head == 0xE5) || (head == 0x00))
return 0;
fIndex[n] = (file*)malloc(sizeof(file));
for (i = 0; i < 8; i++)
fIndex[n]->name[i] = readByte(offSet + n * 32 + i);
for (i = 7; i >= 0; i--) {
if (fIndex[n]->name[i] != 32)
break;
fIndex[n]->name[i] = '\0';
}
return 1;
}
void readFileExt(hWord n) {
int i;
for (i = 0; i < 3; i++)
fIndex[n]->ext[i] = readByte(offSet + n * 32 + 8 + i);
for (i = 3; i >= 0; i--) {
if (fIndex[n]->name[i] != 32)
break;
fIndex[n]->name[i] = '\0';
}
}
void readFileAttr(hWord n) {
fIndex[n]->attr = readByte(offSet + n * 32 + 11);
}
void readFileTimeStamp(hWord n) {
hWord td;
td = readHWord(offSet + n * 32 + 22);
fIndex[n]->ftime.hour = td >> 11;
fIndex[n]->ftime.min = (td >> 5) & 0x3f;
fIndex[n]->ftime.sec = (td & 0x1f) << 1;
td = readHWord(offSet + n * 32 + 24);
fIndex[n]->ftime.year = (td >> 9) + 1980;
fIndex[n]->ftime.mon = (td >> 5) & 0xf;
fIndex[n]->ftime.day = td & 0x1f;
}
void readFileStart(hWord n) {
fIndex[n]->start = readHWord(offSet + n * 32 + 26);
}
void readFileSize(hWord n) {
fIndex[n]->size = readWord(offSet + n * 32 + 28);
}
void readRD() {
hWord i;
for (i = 0; i < nFile; i++) {
if (readFileName(i) > 0) {
readFileExt(i);
readFileAttr(i);
readFileTimeStamp(i);
readFileStart(i);
readFileSize(i);
}
}
}
void printFileName(hWord n) {
hWord i;
printf("%s.%s", fIndex[n]->name, fIndex[n]->ext);
for (i = 0; i < 15 - strlen(fIndex[n]->name) - strlen(fIndex[n]->ext); i++)
printf(" ");
}
void printFileAttr(hWord n) {
hWord i, pt = 0x80;
for (i = 0; i < 8; i++) {
if ((fIndex[n]->attr & pt) == 0)
printf("0");
else
printf("1");
pt >>= 1;
}
printf(" ");
}
void printFileTime(hWord n) {
// print time
if (fIndex[n]->ftime.hour < 10)
printf("0");
printf("%u:", fIndex[n]->ftime.hour);
if (fIndex[n]->ftime.min < 10)
printf("0");
printf("%u:", fIndex[n]->ftime.min);
if (fIndex[n]->ftime.sec < 10)
printf("0");
printf("%u ", fIndex[n]->ftime.sec);
// print date
printf("%2u %3s %4u ", fIndex[n]->ftime.day, month[fIndex[n]->ftime.mon], fIndex[n]->ftime.year);
}
void printFileSize(hWord n) {
printf("%12lu\n", fIndex[n]->size);
}
void cpCluster(FILE *out, hWord cp1) { // function copy, cp1: cluster pointer 1
hWord i;
for (i = 0; i < nBlock; i++) {
readBlock(offSet + ((cp1 - 2) * nBlock + i) * nByte);
fwrite(buff_block, 1, nByte, out);
}
}
void cvt2upper(char *str) {
int i;
for (i = 0; i < strlen(str); i++) {
if ((str[i] >= 97) && (str[i] <= 122))
str[i] -= 32;
}
}
void getTime(mTime *ftime) {
time_t timep;
struct tm *p;
time(&timep);
p = localtime(&timep);
ftime->year = p->tm_year + 1900;
ftime->mon = p->tm_mon + 1;
ftime->day = p->tm_mday;
ftime->hour = p->tm_hour;
ftime->min = p->tm_min;
ftime->sec = p->tm_sec;
}
void writeTime(mTime ftime) {
hWord td;
td = (ftime.hour << 11) + (ftime.min << 5) + (ftime.sec >> 1);
fputc((byte)(td & 0xFF),fp);
fputc((byte)((td >> 8) & 0xFF),fp);
td = ((ftime.year - 1980) << 9) + (ftime.mon << 5) + ftime.day;
fputc((byte)(td & 0xFF),fp);
fputc((byte)((td >> 8) & 0xFF),fp);
}
void init(char *vhdName) {
fp = fopen(vhdName, "rb+");
offSet = 0x1000b; // jump to boot block
nByte = readHWord(offSet);
offSet = 0x1000d;
nBlock = readByte(offSet);
offSet = 0x10010;
nFAT = (hWord)readByte(offSet);
offSet = 0x10011;
nFile = readHWord(offSet);
offSet = 0x10013;
nCluster = readHWord(offSet);
offSet = 0x10016;
nBFAT = readHWord(offSet);
offSet = 0x10400;
readFAT();
offSet += nFAT * nBFAT * nByte;
readRD(); // read root directory
offSet += nFile * 32;
}
void ls() {
hWord i, j;
printf(" id | file name | Attr | timestamp | size \n");
printf("--------------------------------------------------------------------------\n");
for (i = 0; i < nFile; i++) {
if (fIndex[i]) {
if (((fIndex[i]->attr & 8) == 0) & ((fIndex[i]->attr & 4) == 0) & ((fIndex[i]->attr & 2) == 0)) {
printf("%12u ", i);
printFileName(i);
printFileAttr(i);
printFileTime(i);
printFileSize(i);
}
}
}
}
void cp(hWord n) {
char fullName[15];
hWord cp1 = 0;
if (!fIndex[n])
return;
strcpy(fullName, fIndex[n]->name);
strcat(fullName, ".");
strcat(fullName, fIndex[n]->ext);
FILE *out;
out = fopen(fullName, "wb");
cp1 = fIndex[n]->start;
while (cp1 != 0xFFFF) {
cpCluster(out, cp1);
cp1 = FAT[cp1];
}
fclose(out);
}
void rm(hWord n) {
hWord i, j;
hWord cp1 = 0, cp2 = 0;
if (fIndex[n] == NULL) {
printf("file not exists!\n");
return;
}
cp1 = fIndex[n]->start;
while (cp1 != 0xFFFF) {
cp2 = FAT[cp1];
FAT[cp1] = 0x0000;
for (i = 0; i < nFAT; i++) {
fseek(fp, 0x10400 + i * (nBFAT * nByte) + cp1 * 2, SEEK_SET);
fputc(0, fp);
fputc(0, fp);
}
cp1 = cp2;
}
fseek(fp, offSet - nFile * 32 + n * 32, SEEK_SET);
fputc(0xE5, fp);
free(fIndex[n]);
fIndex[n] = NULL;
printf("Done\n");
}
void mv(char *filename){
FILE *p;
word offset;
hWord linkedCluster[32676];
int i, j, k;
int fileNumber;
byte tmp;
file *newFile;
if(strchr(filename, '.') - filename <= 8){
// deal with name and extent
newFile = (file*)malloc(sizeof(file));
strncpy(newFile->name, filename, strchr(filename, '.') - filename);
cvt2upper(newFile->name);
for (i = strlen(newFile->name); i < 8; i++)
newFile->name[i] = ' ';
newFile->name[8] = '\0';
strcpy(newFile->ext, strchr(filename, '.') + 1);
cvt2upper(newFile->ext);
for (i = strlen(newFile->ext); i < 4; i++)
newFile->ext[i] = '\0';
printf("%s %s\n", newFile->name, newFile->ext);
// get size
p = fopen(filename, "rb");//open target file
fseek(p, 0, SEEK_END);
newFile->size = ftell(p);//the size of the target file
fseek(p, 0, SEEK_SET);
// get the clusters to place the file
linkedCluster[0] = (newFile->size - 1) / (nByte * nBlock) + 1;// a cluster occupies 512 bytes
for(i = 2, j = 1; i < nBFAT*nByte && j <= linkedCluster[0]; ++i)
if(FAT[i] == 0)
linkedCluster[j++] = i;
linkedCluster[j] = 0xFFFF;
newFile->start = linkedCluster[1];
// set the attribute
newFile->attr = 0x20;
// update file index list
fileNumber = -1;
while(fIndex[++fileNumber]);
fIndex[fileNumber] = newFile;
// modify root directory
offset = 0x32000 + fileNumber * 0x20;
fseek(fp,offset,SEEK_SET);
for(i = 0; i < 8; ++i)
fputc((byte)newFile->name[i],fp);
for(i = 0; i < 3; ++i)
fputc((byte)newFile->ext[i],fp);
fputc(0x20,fp); // file attr
fseek(fp,10,SEEK_CUR);// escape 10 reserved bytes
/* for(i = 0; i < 4; ++i)//file time and date
fputc((byte)(10),fp);*/
getTime(&(newFile->ftime));
writeTime(newFile->ftime);
fputc((byte)(linkedCluster[1]%256),fp);// first cluster
fputc((byte)(linkedCluster[1]/256),fp);
fputc((byte)((newFile->size) & 0xFF),fp);//file size
fputc((byte)((newFile->size >> 8) & 0xFF),fp);
fputc((byte)((newFile->size >> 16) & 0xFF),fp);
fputc((byte)((newFile->size >> 24) & 0xFF),fp);
// modify FAT
for(i = 1; i <= linkedCluster[0]; ++i){
FAT[linkedCluster[i]] = linkedCluster[i + 1];
offset = 0x10400 + linkedCluster[i] * 2;
fseek(fp, offset, SEEK_SET);
fputc((byte)(linkedCluster[i + 1] & 0xFF), fp);
fputc((byte)(linkedCluster[i + 1] >> 8),fp);
}
//data block
i=0;
j=511;
while(!feof(p)){
if(++j == nByte * nBlock){ // one cluster occupies 1 block
++i;
j = 0;
offset = 0x36000 + (linkedCluster[i] - 2) * (nByte * nBlock);
fseek(fp, offset, SEEK_SET);
for (k = 0; k < nByte * nBlock; k++)
fputc(0, fp);
fseek(fp, offset, SEEK_SET);
}
tmp = fgetc(p);
fputc((byte)(tmp),fp);
}
newFile->name[strchr(filename, '.') - filename] = '\0';
}else{
printf("Invalaid filename.");
}
}
int main() {
char vhdname[16], filename[16];
char cmd[20];
int id;
printf("Please input the name of VHD:\n");
scanf("%s", vhdname);
init(vhdname);
while (1) {
printf("What do you want to do?\n");
scanf("%s", cmd);
if (strcmp(cmd, "help") == 0) {
printf("ls -- list out files and info\n");
printf("cp -- copy a file from vhd out\n");
printf("mv -- move a file from outside into vhd\n");
printf("rm -- remove a file from vhd\n");
printf("exit -- exit the program\n");
}
else if (strcmp(cmd, "ls") == 0) {
ls();
}
else if (strcmp(cmd, "cp") == 0) {
printf("Please input the file id u want to copy out:\n");
scanf("%d", &id);
cp(id);
}
else if (strcmp(cmd, "mv") == 0) {
printf("Please: input the file you want to add into the visual disc.\nFilename: ");
scanf("%s",filename);
mv(filename);
}
else if (strcmp(cmd, "rm") == 0) {
printf("Please input the file id you want to remove:\n");
scanf("%d", &id);
rm(id);
}
else if (strcmp(cmd, "exit") == 0) {
exit(0);
}
else {
printf("Please input the right command, input 'help' for more infomation.\n");
}
}
}