code: public function GIFGetByte($len)
      {
          $this->GIF_buffer = [];
  
          for ($i = 0; $i < $len; $i++) {
              if ($this->GIF_bfseek > strlen($this->GIF_stream)) {
                  return 0;
              }
              $this->GIF_buffer[] = ord($this->GIF_stream{$this->GIF_bfseek++});
          }
          return 1;
      }
docs: /*
  
  05.06.2007.
  Made a little modification
  
  
  -    function GIFGetByte ( $len ) {
  -        $this->GIF_buffer = array ( );
  -
  -        for ( $i = 0; $i < $len; $i++ ) {
  +            if ( $this->GIF_bfseek > strlen ( $this->GIF_stream ) ) {
  +                return 0;
  +            }
  -            $this->GIF_buffer [ ] = ord ( $this->GIF_stream { $this->GIF_bfseek++ } );
  -        }
  +        return 1;
  -    }