/**
  * Process the copyright tags.
  *
  * @param int $commentStart The position in the stack where
  *                          the comment started.
  *
  * @return void
  */
 protected function processCopyrights($commentStart)
 {
     $copyrights = $this->commentParser->getCopyrights();
     /** @var PHP_CodeSniffer_CommentParser_SingleElement $copyright */
     foreach ($copyrights as $copyright) {
         $errorPos = $commentStart + $copyright->getLine();
         $content = $copyright->getContent();
         if ($content !== '') {
             $matches = array();
             if (preg_match('~^.*?(\\d{4})(?:(.)(\\d{4}))? (.+)$~', $content, $matches) !== 0) {
                 // Check earliest-latest year order.
                 if ($matches[2] > '') {
                     if ($matches[2] != '-') {
                         $error = 'A hyphen must be used between the earliest and latest year';
                         $this->currentFile->addError($error, $errorPos, 'CopyrightHyphen');
                     }
                     if (0 < $matches[3] && $matches[3] < $matches[1]) {
                         $error = "Invalid year span \"{$matches['1']}{$matches['2']}{$matches['3']}\" found; consider \"{$matches['3']}-{$matches['1']}\" instead";
                         $this->currentFile->addWarning($error, $errorPos, 'InvalidCopyright');
                     }
                 }
             } else {
                 $error = '@copyright tag must contain a year and the name of the copyright holder';
                 $this->currentFile->addError($error, $errorPos, 'EmptyCopyright');
             }
         } else {
             $error = '@copyright tag must contain a year and the name of the copyright holder';
             $this->currentFile->addError($error, $errorPos, 'EmptyCopyright');
         }
     }
 }