Plugin idea so simple, can not be found

 function pagePost($content)
  {
	  $minWordsFirstPage = 350;
	  $minSentancesFirstPage = 15;
	  $sentancesFirstPageRange = 5;
	  $minWordsRequiredToPage = 650;
	  
	  $words = explode(' ', $content);
	  
	  //check to see if there are enough words in the post to determine if paging is needed
	  if( count($words) > $minWordsRequiredToPage )
	  {
		  $words = 0;
		  $sentancesToAdd = 0;
		  do {
			  	//check to see if there are enough words on the first page.
				//if not lets add some more words
				if (count($words) >= $minWordsFirstPage) {
					break;
				}
				else
				{
					//lets add a bit of simple randomization to the number of sentances on the first page
					$sentancesFirstPage = rand( $minSentancesFirstPage, $minSentancesFirstPage + $sentancesFirstPageRange);
					$sentancesFirstPage = $sentancesFirstPage + $sentancesToAdd;

					$sentances = explode('.', $content, $sentancesFirstPage);
					
					$sentancesTemp = $sentances;
					$sentancesTemp[$sentancesFirstPage] = '';
					$firstPageText = implode('.', $sentancesTemp);
					$words = explode(' ', $firstPageText);

					$sentancesToAdd = $sentancesToAdd + 5;
				}
				
			} while (0);
			
		//now lets add the nextpage tag for our page
		$sentances[$sentancesFirstPage - 2] =  $sentances[$sentancesFirstPage - 2] . '<!--nextpage-->';
		$content = implode('.', $sentances);	
	  }
	  return $content;
  }

wordpress.org/extend/plugins/wp-limit-posts-automatically/