pset4 recover compiled, no output

Question

The code compiled successfully, but only made two files 000.jpeg and 001.jpeg. I also cannot open these two files. I used valgrind to check if any memory issues. It's all good. Can I read one byte at a time when looking for jpeg signature and write a block of 512 when writing to new file? I don't know why there are only two output files? when I tried to open 001.jpeg. it shows "Unknown error: File size is bigger than allowed (8MB). Size is 16342528 bytes". why does the code keep writing into one file?

Here is my code:

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

#define BLOCK_SIZE 512

typedef uint8_t BYTE;

int main (void)
{
    //open the file to be recovered
    FILE* in_file = fopen("card.raw", "r");

    //check if file can be open
    if (in_file == NULL)
    {
        printf("cannot open the file\n");
        return 1;
    }

    //one block
    BYTE buffer[BLOCK_SIZE];

    //open a new file
    FILE* image = NULL;

    //keep track of how many images have been recovered
    int counter = 0;

    //read all blocks until end of file
    while(fread(&buffer, sizeof(BYTE) * BLOCK_SIZE, 1, in_file) == 1)
    {
        //iterate through each block
        for (int i = 0; i < BLOCK_SIZE; i++)
        {
            fread(&buffer[i], sizeof(BYTE), 1, in_file);
        }

        //if find a jpeg image
        if (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff && 
            (buffer[3] == 0xe0 || buffer[3] == 0xe1))
        {
            //make sure start writing in a new file
            if (image != NULL)
            {
                fclose(image);
            }

            char title[3];

            //write a new file
            sprintf(title, "%03d.jpg", counter);
            counter++;

            image = fopen(title, "a");

            //make sure open a file successfully
            if (image == NULL)
            {
                printf("Could not write the file.\n");
                return 2;
            }

            //write a block
            fwrite(&buffer, sizeof(BYTE) * BLOCK_SIZE, 1, image);
        }

        //write in existing file
        else if (image != NULL)
        {
            fwrite(&buffer, sizeof(BYTE) * BLOCK_SIZE, 1, image);
        }
    }

    //close input file
    fclose(in_file);

    return 0;
}

Answer 1

First question: what is the string length (including the end of string marker) of the name of a file?

            char title[3];

Once that's fixed, the next problem is how the end of file condition for the input file is handled. The code currently reads a block of data from the input file, processes it, and then checks to see if end of file has been detected. Because of this, an extra block of data will be added to the last file.

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