Read data from a disk in c++

Question

I'm trying to read some data that lies outside of the partition table, I can successfully read the raw data, but it appears to be encoded in Unicode (UTF-8) or something. There is an application that has been written to read this data and display it properly so I know it can be done.

This data is called "Image Safe Data" and it is something Novell ZenWorks places on the disk at the sixth sector (0x05).

The raw data looks like this:

ZISD♂   Æ☻      ☺   └¿ ├└¿ ☺    ñ3åG    ╓ï╝Y    ≡   ♣   §   ╗ç9%¥⌂+0Kâ¬ê


  :☺               @   f 8 b 3 4 6 6 2 9 3 b 3 2 b b f d c 8 c b d 6 2 2 1 2 1 0 d
2 1 ♫   M H S T R E E ▬   F H I F L 0 0 0 5 9 3     L   \ \ F H 0 1 F S N T H 0
9 \ A P P S \ i m g s \ C X P P N 6 7 1 0 B . z m g $   t r i n i t y - h e a l
 t h . o r g ▬   F H I F L 0 0 0 5 9 3 H   Z N W

I wrote the following code to read the data directly from disk in C++:

#include <iostream>
#include <windows.h>


void main() {
    DWORD nRead;
    char buf[512];

    HANDLE hDisk = CreateFile("\\\\.\\PhysicalDrive0", 
        GENERIC_READ, FILE_SHARE_READ,        
        NULL, OPEN_EXISTING, 0, NULL);

    SetFilePointer(hDisk, 0xA00, 0, FILE_BEGIN);
    ReadFile(hDisk, buf, 512, &nRead, NULL);
    for (int currentpos=0;currentpos < 512;currentpos++) {
        std::cout << buf[currentpos];
    }
    CloseHandle(hDisk);
}

I'm a novice in C++. I need to find a way to output this data so that it can be read by a script if possible. It looks to be delimited by inconsistent characters.

Answer 1

When you print it you're interpreting the data as a char . Some of the values are in the a-zA-Z "normal, printable" range and so print as you'd expect. Others, like '0' are special and unprintable directly. You probably want to print the bytes as hex, not characters. To do that:

std::cout << std::hex << std::setw(2) << std::setfill('0') << unsigned(buf[currentpos]) << " ";

This tells the ostream to print two digits of hex, using 0 if there's less and then forces the char to be printed as an unsigned int.

(If you're interested in learning more about C++ you could also use std::copy and std::ostream_iterator to avoid writing the loop yourself)