PHP keyword replacement class (avoid repeated replacement, retain and restore the original link)

 /*
 * Keyword matching class
 * @author ylx
 * @packet mipang
 * Usage examples
 * $str = "The green-shelled laying hen spreads Van der Sar next year, and the next year 1 spreads open the room Lucas local army";
 * $key = new KeyReplace($str,array("xxxx"=>"sadf", "Next year 1" =>'http://baidu.com',"Next year" =>'google.com'));
 * echo $key->getResultText();
 * echo $key->getRuntime();
 */
class KeyReplace
{
 private $keys = array();
 private $text = "";
 private $runtime = 0;
 private $url = true;
 private $stopkeys = array();
 private $all = false;
 /**
 * @access public
 * @param string $text specifies the article to be processed
 * @param array $keys specifies the dictionary phrase array(key=>url,...) url can be an array, if it is an array it will be replaced randomly One of them
 * @param array $stopkeys specifies stop words array(key,...) The words in this will not be processed
 * @param boolean $url true means to replace it with a link, otherwise it will only be replaced
 * @param boolean $all true means replace all found words, otherwise only replace the first time
*/
 public function __construct($text='',$keys=array(),$url=true,$stopkeys=array (),$all=false) {
 $this->keys = $keys;
 $this->text = $text;
 $this->url = $url;
 $this->stopkeys = $stopkeys;
 $this->all = $all;
 }
 /**
 * Get the processed article
 * @access public
 * @return string text
*/
 public function getResultText() {
 $start = microtime(true);
 $keys = $this->hits_keys();
 $keys_tmp = array_keys($keys);
 function cmp($a, $b ){
 if (mb_strlen($a) == mb_strlen($b)) {
 return 0;
 }
 return (mb_strlen($a)  }< ;/p>
 usort($keys_tmp,"cmp");
 foreach($keys_tmp as $key){
 if( is_array($keys[$key])){
 $url = $keys[$key][rand(0,count($keys[$key])-1)];
 }else
 $url = $keys[ $key];
 $this->text = $this->r_s($this->text,$key,$url);
 }
 $this->runtime = microtime(true)-$start;
 return $this->text;
 }
 /**
 * Get processing time
 * @access public
 * @return float
*/
 public function getRuntime() {
 return $this->runtime;
 }
 /**
 * Set keywords
 * @access public
 * @param array $keys array(key=>url,...)
 */
 public function setKeys($keys) {
 $this->keys = $keys;
 }
 /**
 * Set stop words
 * @access public
 * @param array $keys array(key,...)
* /
 public function setStopKeys($keys) {
 $this->stopkeys = $keys;
 }
 /**
 * Set article
 * @access public
 * @param string $text
*/
 public function setText($text) {
 $this->text = $text;
 }
 /**
 * Used to find the hit keywords in the string
 * @access public
 * @return array $keys Returns the matched word array(key=>url,...)
*/
 public function hits_keys(){
 $ar = $this->keys;
 $ar = $ar?$ar:array();
 $result=array();
 $ str = $this->text;
 foreach($ar as $k=>$url){
 $k = trim($k);
 if(!$k)
 continue;
 if(strpos($ str,$k)!==false && !in_array($k,$this->stopkeys)){
 $result[$k] = $url;
 }
 }
 return $result?$result:array( );
 }
  /**
 * Used to find the hit stop words in the string
 * @access public
 * @return array $keys Returns the matched word array(key,...)
*/
  public function hits_stop_keys(){
    $ar = $this->stopkeys;
    $ar = $ar?$ar:array();
    $result=array();
    $str = $this->text;
    foreach($ar as $k){
      $k = trim($k);
      if(!$k)
 continue;
      if(strpos($str,$k)!==false && in_array($k,$this->stopkeys)){
 $result[] = $k;
      }
    }
    return $result?$result:array();
  }
  /**
 * Handle the replacement process
 * @access private
 * @param string $text The person being replaced
 * @param string $key Keywords
 * @param string $url Link
 * @return string $text The processed article
*/
  private function r_s($text,$key,$url){
    $tmp = $text;
    $stop_keys = $this->hits_stop_keys();
    $stopkeys = $tags = $a = array();
    if(preg_match_all("#]+>[^]*>#su",$tmp,$m)){
      $a=$m[0];
      $tmp = preg_replace("#(?![_s|[_a|[_|[_t|[_ta|[_tag)".$key1."(?!agd+_]|gd+_]|d+_]|sd+_]|_])#us",''.$key.'',$tmp,$this->all?-1:1);
    else
      $tmp = preg_replace("#(?![_s|[_a|[_|[_t|[_ta|[_tag)".$key1."(?!agd+_]|gd+_]|d+_]|sd+_]|_])#us",$url,$tmp,$this->all?-1:1);
    if(!empty($a)){
      foreach($a as $n=>$at){
 $tmp = str_replace("[_a".$n."_]",$at,$tmp);
      }
    }
    if(!empty($tags)){
      foreach($tags as $n=>$at){
 $tmp = str_replace("[_tag".$n."_]",$at,$tmp);
      }
    }
    if(!empty($stopkeys)){
      foreach($stopkeys as $n=>$at){
 $tmp = str_replace("[_s".$n."_]",$at,$tmp);
      }
    }
    return $tmp;
  }
}