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<b>Warning</b>:  session_start(): open(/var/lib/php/sessions/sess_4aov56ol0jkitasbne9i6epshd, O_RDWR) failed: No space left on device (28) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
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<b>Warning</b>:  session_start(): Failed to read session data: files (path: /var/lib/php/sessions) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
static int compareBWImagesByScanlineOrdering(BWImage a, BWImage b) {
  assertSameSize(a, b);
  int w = a.getWidth(), h = a.getHeight();
  for y to h:
    for x to w: {
      int pix1 = a.getInt(x, y), pix2 = b.getInt(x, y);
      if (pix1 != pix2) ret pix1-pix2;
    }
  ret 0;
}