PSET4 - recovery, problem with writting jpegs after start

Question

include <stdio.h>

include <stdlib.h>

typedef uint8_t byte;

define SI 512

int main(int argc, char* argv[]) {

FILE* card = fopen("card.raw", "r");
if (card == NULL)
{
    fclose(card);
    printf("Unable to open a file\n");
    return 1;
}


byte buffer[SI];
char title[8];

int counter = 0;
FILE* pic = NULL;

//when card can be read
while(fread(buffer,sizeof(byte),SI,card) == SI)
{
    
   
    //check for jpg
    if((buffer[0] == 0xFF && buffer[1] == 0xd8 && buffer[2] == 0xff) && buffer[3] >= 0xe0 && buffer[3] <= 0xef)        {
        
        if(open == 1)
        {
            open = 0;
            fclose(pic);
        }
        
        sprintf(title,"%03d.jpg",counter);
        //open a first picture file to write into
        pic = fopen(title, "a");
        //check if the file exist
        if(pic == NULL)
        {
            printf("This file doesnt exist\n");
            fclose(pic);
            return 2;
        }
        //write the beginning of the first file into pic file
       
         open = 1;
         counter++;
         //write the rest of bytes
          
          
    }
    //if file is open write in bytes Blocks
    if(open == 1)
    {
        fwrite(buffer,sizeof(byte),SI,pic);
    }
        
     
    
       
}
fclose(pic);
fclose(card);
return 0;

}

Answer 1

First, you aren't checking the jpeg signature fully. The fourth byte could be any value between 0xe0' and0xef`, not only the two values you are checking.

Then,your code only writes the first 512 bytes because you are not handling the possibility of multiple buffers into one single file.

In fact, I can see the comment //write the beginning of the first file ..., but I don't see any //write the next 512 bytes into file ... or so comment.