I've been watching the lectures from Harvards introductory programming course cs50 and working through the problem sets to learn programming. I'm currently working on pset5 and would like some feedback on the last part of the problem set, image recovery. The goal is to write a program that recovers 50 jpgs from a "forensic image" of a Compact Flash card and name them from 001.jpg to 050.jpg. The program works but I'm not sure If I solved the problem correctly. How badly designed is this implementation ?
Thanks.
Code:/**************************************************************************** * recover.c * * Computer Scince 50 * Problem Set 5 * * Recovers jpg images from image card.raw ****************************************************************************/ #include <cs50.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> typedef uint8_t BYTE; int main(void) { // open card.raw file FILE *inptr = fopen ("card.raw", "r"); if (inptr == NULL) { printf("could not open card.raw file\n"); return 1; } // size of a block in FAT file system int block_size = 512; // buffer store one block BYTE buffer[block_size]; // store image filename char image_name[8]; // recovered jpgs will be named with a number starting from 1 int number = 1; // keep track of when an image is found bool image_found = false; // pointer to current jpeg file on hard disk FILE *outptr = NULL; // look for jpgs until EOF is reached while (feof(inptr) == false) { // read 512 btye block into buffer fread(buffer, block_size, 1, inptr); // check buffer for jpeg signature if (buffer[0] == 255 && buffer[1] == 216 && buffer[2] == 255 && (buffer[3] == 224 || buffer[3] == 225)) { // if a previous jpeg was found close file if (image_found == true) { fclose(outptr); } image_found = true; // name new image sprintf(image_name, "%.3d.jpg", number); number++; // create new jpg image file on hard disk outptr = fopen (image_name, "w"); if (outptr == NULL) { printf("could not create jpeg file\n"); return 2; } // write 512 byte block to jpg file on disk fwrite(buffer, block_size, 1, outptr); } // continue writing parts of a jpg to file on disk else if (image_found == true) { fwrite(buffer, block_size, 1, outptr); } } // close card.raw fclose(inptr); // close last jpg fclose(outptr); return 0; }
