IRI::is_valid(): bool

679    public function is_valid()680    {681        if ($this->ipath === '') {682            return true;683        }684 685        $isauthority = $this->iuserinfo !== null || $this->ihost !== null ||686            $this->port !== null;687        if ($isauthority && $this->ipath[0] === '/') {688            return true;689        }690 691        if (!$isauthority && (substr($this->ipath, 0, 2) === '//')) {692            return false;693        }694 695        // Relative urls cannot have a colon in the first path segment (and the696        // slashes themselves are not included so skip the first character).697        if (!$this->scheme && !$isauthority &&698            strpos($this->ipath, ':') !== false &&699            strpos($this->ipath, '/', 1) !== false &&700            strpos($this->ipath, ':') < strpos($this->ipath, '/', 1)) {701            return false;702        }703 704        return true;705    }