recover.c

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

typedef uint8_t BYTE;

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        printf("Usage: ./recover image");
        return 1;
    }

    // Original file
    FILE *file = fopen(argv[1], "r");
    
    if (file == NULL)
    {
        printf("Usage: ./recover image");
        return 1;
    }
    
    // file will be written into
    FILE *img = NULL;
    char filename[8];
    
    int counter = 0;
    int i = 0;
    
    BYTE buffer[512];
    while(fread(buffer, 512, 1, file) == 1)
    {
        if (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff && (buffer[3] & 0xf0) == 0xe0)
        {
            i = 1;
            if (counter == 0)
            {
                sprintf(filename, "%03i.jpg", counter);
                img = fopen(filename, "w");
                fwrite(buffer, 512, 1, img);
                counter++;
            }
            else
            {
                fclose(img);
                sprintf(filename, "%03i.jpg", counter);
                img = fopen(filename, "w");
                fwrite(buffer, 512, 1, img);
                counter++;
            }
            
        }
        else
        {
            if (i == 0)
            {
                continue;
            }
            else
            {
                fwrite(buffer, 512, 1, img);
            }
        }
    }
    fclose(img);
    fclose(file);
}