recover_unsupported.c

// recovers jpegs from memory card file
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <cs50.h>

#define BLOCK 512

typedef uint8_t  BYTE;

int main (int argc, char* argv[]) {
    // insure proper usage
    if (argc != 2) {
        fprintf(stderr, "Usage: ./recover image\n");
        return 1;
    }
    // remember forensic image name
    char* raw = argv[1];
    // open card for reading
    FILE* raw_file = fopen(raw, "r");
    if (raw_file == NULL) {
        fprintf(stderr, "Could not open %s.\n", raw);
        return 2;
    }
    // index of jpg written files
    int i = 0;
    // array of 512 Bytes
    BYTE jpg[BLOCK];
    // open the very first file for reading
    char file_name[3];
    sprintf(file_name, "%03i.jpg", i);
    FILE* recovery = fopen(file_name, "w");
    // to indicate if we already found a file or not
    bool already_found = false;
    while (!feof(raw_file)) {
        fread(jpg, 512, 1, raw_file);
        if ((jpg[0] == 0xff && jpg[1] == 0xd8 && jpg[2] == 0xff
        && (jpg[3] & 0xf0) == 0xe0)) {
            if (already_found == true) {
                // close current file
                fclose(recovery);
                // open a new file
                i++;
                sprintf(file_name, "%03i.jpg", i);
                recovery = fopen(file_name, "w");
            }
            // write the current header into the file
            fwrite(jpg, 512, 1, recovery);
            already_found = true;
        }
        else if (already_found == true) {
            // write the current header into the file
            fwrite(jpg, 512, 1, recovery);
        }
    }
}