recover.c

/**
 * recover.c
 *
 * Computer Science 50
 * Problem Set 4
 *
 * Recovers JPEGs from a forensic image.
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

typedef uint8_t  BYTE;

int main(void)
{
    // open CF card
    FILE* inptr = fopen("card.raw", "r");
    if (inptr == NULL)
    {
        printf("Could not open \n");
        return 1;
    }



    int j = 0;     // counter for jpeg file
    char title[8];  // file name for jpeg file
    BYTE block[512]; // 512byte chunk of memory


    while(!feof(inptr))
    {

        fread(block, sizeof(block), 1, inptr);

        if(block[0] == 0xff && block[1] == 0xd8 && block[2] == 0xff && (block[3] >= 0xe0 && block[3] <= 0xef))
        {

            sprintf(title, "%03d.jpg", j);
            j++;

            FILE* outptr = fopen(title,"a");

            do
            {
                fwrite(block, sizeof(block), 1, outptr);
                fread(block, sizeof(block), 1, inptr);
            } while(block[0] != 0xff || block[1] != 0xd8 || block[2] != 0xff || (block[3] < 0xe0 || block[3] > 0xef));

            fclose(outptr);

        }

    }
    fclose(inptr);


    return 0;
}