SysII-FS/FSreadfile.java at master · AmhCS/SysII-FS · GitHub

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packageexternal_tools;

importjava.io.*;

publicclassFSreadfile {

privateStringf;
privateRandomAccessFilefile;
privatelongdirectoryBlockPos = 4096;

publicvoidstart(Stringf, Stringfilename) {
try {
file = newRandomAccessFile(filename,"rw");
intblockNum = getBlockNum(f);
readFile(blockNum);
	}
catch ( IOExceptione ) {
System.out.print("IO Exception - BlockDevice file not found.");
	}
 }

privateintgetBlockNum(Stringf) throwsIOException {
//A byte equal to null is 0x00000000
longcurrPos = directoryBlockPos;
while ( currPos <= 8191 ) {
file.seek(currPos);
byte[] bytes = newbyte[12];
char[] chars = newchar[12];
intc = 0;
while ( c < 12 ) {
bytes[c] = (byte)file.read();
chars[c] = (char)bytes[c];
if ( (int)chars[c] == 0 ) {
break;
 }
c++;
 }
Strings = "";
c = 0;
while ( c < 12 ) {
if ( (int)chars[c] == 0 ) {
break;
 }
s += chars[c];
c++;
 }
if ( s.equals(f) ) {
currPos += 12;
file.seek(currPos);
intblock = file.readInt();
if ( block == 0 ) {
thrownewRuntimeException("File was deleted.");
 }
returnblock;
 }
currPos += 16;
	}

if ( currPos > 8191 ) {
thrownewRuntimeException("File not found.");
	}

return0;
 }

privatevoidreadFile(intblockNum) throwsIOException {
//Iterate to inode
longinodePos = 8192;
intc = blockNum;
while ( c > 2 ) {
inodePos += 4096;
c--;
	}

file.seek(inodePos);

//Read immediate data
c = 0;
while ( c < 2044 ) {
System.out.print(""+(char)file.readByte());
c++;
	}

//Loop through direct indices, printing out 4096 chars at a time
inodePos += 2048;
while ( true ) {
file.seek(inodePos);
longpos = 8192;
c = file.readInt();
if ( c == 0 ) {
break;
 }
inodePos += 4;
while ( c > 2 ) {
pos += 4096;
c--;
 }

file.seek(pos);

c = 0;
while ( c < 4096 ) {
System.out.print(""+(char)file.readByte());
c++;
 }
	}
 }

}