set 4 - I don't know why I only get part of the image

Question

I don't know why my code isn't working. It recovers images but only a small fuzzy part of them. Can anyone help?

/** * recover.c * * Computer Science 50 * Problem Set 4 * * Recovers JPEGs from a forensic image. */

include

include

include

typedef uint8_t BYTE; int main(int argc, char* argv[]) { // open memory card file char picture[8]; BYTE block[512]; int counter = 0;

FILE* inptr = fopen("card.raw", "r");
if(inptr == NULL)
{
    printf("could not open file/n");
    return 1;
}
FILE* outptr;
while(fread(&block, 512, 1, inptr) > 0)
{

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

            if( counter > 0)
            {
                fclose(outptr);
                sprintf(picture, "%d.jpg", counter);
                counter++;
                outptr = fopen(picture, "w");
            }  

            if( counter == 0)
            {
                sprintf(picture, "%d.jpg", counter);
                counter++;
                outptr = fopen(picture, "w");
                if (outptr == NULL)
                {
                    printf("could not create /n");
                    return 2;
                }
            }

            fwrite(&block, 512, 1, outptr);

        }  


}
fclose(inptr);

}

Answer 1

You are only writing the first block of each file, which contains the signature, to the output file. All of the following blocks (which will not have a jpeg signature), meaning the rest of the image, are being discarded because there is no code to handle them.

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