Faster_Image_B52f1a8_Exif_Parser::parseExifIfd PHP Метод

    protected function parseExifIfd()
    {
        $byte_order = $this->stream->read(2);
        switch ($byte_order) {
            case 'II':
                $this->short = 'v';
                $this->long = 'V';
                break;
            case 'MM':
                $this->short = 'n';
                $this->long = 'N';
                break;
            default:
                throw new Faster_Image_B52f1a8_Invalid_Image_Exception();
                break;
        }
        $this->stream->read(2);
        $offset = current(unpack($this->long, $this->stream->read(4)));
        $this->stream->read($offset - 8);
        $tag_count = current(unpack($this->short, $this->stream->read(2)));
        for ($i = $tag_count; $i > 0; $i--) {
            $type = current(unpack($this->short, $this->stream->read(2)));
            $this->stream->read(6);
            $data = current(unpack($this->short, $this->stream->read(2)));
            switch ($type) {
                case 0x100:
                    $this->width = $data;
                    break;
                case 0x101:
                    $this->height = $data;
                    break;
                case 0x112:
                    $this->orientation = $data;
                    break;
            }
            if (isset($this->width) && isset($this->height) && isset($this->orientation)) {
                return true;
            }
            $this->stream->read(2);
        }
        return false;
    }