Efficiently detect corrupted jpeg file?

Question

Is there an efficient way of detecting if a jpeg file is corrupted?

Background info:
  solutions needs to work from within a php script
  the jpeg files are on disk
  manual checking is no option (user uploaded data)

I know that imagecreatefromjpeg(string $filename); can do it. But it is quite slow at doing so.

Does anybody know a faster/more efficient solutions?

Answer 1

From the command line you can use jpeginfo to find out if a jpeg file is OK or not.

$ jpeginfo -c test.jpeg

test.jpeg 260 x 264 24bit JFIF N 15332 [OK]

It should be trivial to call jpeginfo from php.

Answer 2

My simplest (and fastest) solution:

function jpeg_file_is_complete($path) {
    if (!is_resource($file = fopen($path, 'rb'))) {
        return FALSE;
    }
    // check for the existence of the EOI segment header at the end of the file
    if (0 !== fseek($file, -2, SEEK_END) || "\xFF\xD9" !== fread($file, 2)) {
        fclose($file);
        return FALSE;
    }
    fclose($file);
    return TRUE;
}

function jpeg_file_is_corrupted($path) {
    return !jpeg_file_is_complete($path);
}

Note: This only detects a corrupted file structure, but does NOT detect corrupted image data.