public function getCrossReference()
    {
        if ($this->xref === null) {
            $this->xref = new CrossReference($this, $this->resolveFileHeader());
        }

        return $this->xref;
    }
public function getCrossReference()
    {
        if ($this->xref === null) {
            $this->xref = new CrossReference($this, $this->resolveFileHeader());
        }

        return $this->xref;
    }
public function getCrossReference ( ) { if ( $ this -> xref === null ) { $ this -> xref = new CrossReference ( $ this , $ this -> resolveFileHeader ( ) ) ; } return $ this -> xref ; }
Get the cross reference instance.

@return CrossReference
@throws CrossReferenceException
@throws PdfParserException
Get the cross reference instance .