recover.c

#include <stdio.h>
#include <stdlib.h>

//TODO
// Figure out how to detect the end of the file an stop
// Figure out what the nth piece of buffer contains when it reads into it from the final chunk
// ie when it runs out of infile, and tries to read that into buffer, what does buffer[i] then contain?
// use that as condition either
// a) in an if () branch on line 77 OR
// b) as an extra criteria in the while loop beginning line 80

int main(int argc, char *argv[])
{
    // Ensure proper usage
    if (argc != 2)
    {
        fprintf(stderr, "Usage: ./recover file-to-recover\n");
        return 1;
    }

    // Open infile
    char *infile = argv[1];
    FILE *inptr = fopen(infile, "r");

    // Error check for blank infile
    if (inptr == NULL)
    {
        fprintf(stderr, "Infile is blank\n");
        return 2;
    }

    // Create array for storing read data
    unsigned char buffer[512];
    // number of JPEGs found
    int pic_counter = 0;
    // Filename of new pic
    char new_pic[8];
    // Read first 512 bytes of infile into a buffer

    do
    {
        fread(&buffer, 1, 512, inptr);
        // condition for when a jpeg is found

    }
    while (!(buffer[0] == 0xff &&
             buffer[1] == 0xd8 &&
             buffer[2] == 0xff &&
             (buffer[3] & 0xf0) == 0xe0));

    do
    {
        // create new jpeg of format "002.jpg"
        sprintf(new_pic, "%03i.jpg", pic_counter);
        FILE *img = fopen(new_pic, "w");

        // write to new_pic once
        // Suspect this might be adding one chunk too many?
        fwrite(&buffer, 1, 512, img);

        // keep reading and writing to new pic until new JPEG is hit
        do
        {
            fread(&buffer, 1, 512, inptr);
            if (feof(inptr))
            {
                break;
            }
            fwrite(&buffer, 1, 512, img);
        }
        while (!(buffer[0] == 0xff &&
                 buffer[1] == 0xd8 &&
                 buffer[2] == 0xff &&
                 (buffer[3] & 0xf0) == 0xe0));

        // add one to pic counter
        pic_counter++;

        // close outfile
        fclose(img);
        // print current pic counter
        printf("Pic counter is %i\n", pic_counter);
    }
    while (pic_counter < 100);

    // close infile
    fclose(inptr);

    // Success
    return 0;
}