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Fixed sizeof() problems and logic problems
Source Link
Ha Tran
Ha Tran
  • 74
  • 6

**** UPDATE I hope it is less a mess now. It recovers all images, not invalid anymore but images return chessboard patterns. Any leads why?

while (fread(&buffer, 512, 1, infile) != 0)
    {
        FILE *img = NULL;
        if (buffer[0] == 0xff &&
            buffer[1] == 0xd8 &&
            buffer[2] == 0xff &&
            (buffer[3] & 0xf0) == 0xe0)
            {
                if (img == NULL)
                {
                    sprintf(filename, "%03i.jpg", count);
                    img = fopen(filename,"w");
                    fwrite(&buffer, 512, 1, img);
                    count++;
                }
                else if (img != NULL)
                {
                    fclose(img);
                    sprintf(filename, "%03i.jpg", count);
                    img = fopen(filename, "w");
                    fwrite(&buffer, 512, 1, img);
                    count++;
                }
            }
        else
        {
            if (img != NULL)
            {
                fwrite(&buffer,512,1,img);
            }
            else if (img == NULL)
            {
                continue;
            }
        }
    }
    fclose(infile);
}

**** UPDATE I hope it is less a mess now. It recovers all images, not invalid anymore but images return chessboard patterns. Any leads why?

while (fread(&buffer, 512, 1, infile) != 0)
    {
        FILE *img = NULL;
        if (buffer[0] == 0xff &&
            buffer[1] == 0xd8 &&
            buffer[2] == 0xff &&
            (buffer[3] & 0xf0) == 0xe0)
            {
                if (img == NULL)
                {
                    sprintf(filename, "%03i.jpg", count);
                    img = fopen(filename,"w");
                    fwrite(&buffer, 512, 1, img);
                    count++;
                }
                else if (img != NULL)
                {
                    fclose(img);
                    sprintf(filename, "%03i.jpg", count);
                    img = fopen(filename, "w");
                    fwrite(&buffer, 512, 1, img);
                    count++;
                }
            }
        else
        {
            if (img != NULL)
            {
                fwrite(&buffer,512,1,img);
            }
            else if (img == NULL)
            {
                continue;
            }
        }
    }
    fclose(infile);
}
Source Link
Ha Tran
Ha Tran
  • 74
  • 6

Pset4 recover invalid or unsupported

I have been pulling my hair for recover 2 weeks by now. I finally got it to print 50 files at last. However, they are all invalid . Can anyone help me out?

while (fread(&buffer, sizeof(buffer), 1, infile) == 1) // if fread return anything smaller than 1 then it's EOF
    {
        //fread(&buffer, sizeof(buffer), 1, infile); (this line is causing files not reach 49 files, for some reasons)
        //check if block is beginning of jpeg
        if (buffer[0] == 0xff &&
            buffer[1] == 0xd8 &&
            buffer[2] == 0xff &&
            (buffer[3] & 0xf0) == 0xe0)
            {
                //Create new file to store jpg 
                sprintf(filename, "%03i.jpg", count);
                // Here we open the img file
                FILE *img = fopen(filename, "w");
                // if there is a JPEG file already opened
                // close it.
                // then open the next file
                if (img != NULL)
                {
                    fclose(img);
                    img = fopen(filename,"w");
                }
                //write to the new file 512 bytes/block a time while byte is not JPEG beginning
                while  (buffer[0] != 0xff &&
                        buffer[1] != 0xd8 &&
                        buffer[2] != 0xff &&
                        (buffer[3] & 0xf0) != 0xe0)
                {
                    fwrite(&buffer, sizeof(buffer), 1, img);
                }
                count++;
                fclose(img);
            }
    }
    fclose(infile);
}

Thank you in advance.