<?php
/** string filter class
 * Date:   2013-01-09
 * Author:  fdipzone
 * Ver:   v1.0
 *
 * Func:
 * public replace      替換非法字元
 * public check       檢查是否含有非法字元
 * private protect_white_list 保護白名單
 * private resume_white_list 還原白名單
 * private getval       白名單 key轉為value
 */
class StrFilter{ // class start
 
private $_white_list = array();
private $_black_list = array();
private $_replacement = '*';
private $_LTAG = '[[##';
private $_RTAG = '##]]';
/**
     * @param Array $white_list
     * @param Array $black_list
     * @param String $replacement
     */
public function __construct($white_list=array(), 
 
$black_list=array(), $replacement='*'){
$this->_white_list = $white_list;
$this->_black_list = $black_list;
$this->_replacement = $replacement;
    }
/** 替換非法字元
     * @param String $content 要替換的字串
     * @return String     替換後的字串
     */
public function replace($content){
if(!isset($content) || 
 
$content==''){
return '';
        }
// protect white list
$content = $this->protect_white_list($content);
// replace black list
if($this->_black_list){
foreach($this->_black_list as $val){
$content = str_replace($val, $this->_replacement, $content);
            }
        }
return $content;
// resume white list
$content = $this->resume_white_list($content);
return $content;
    }
/** 檢查是否含有非法自符
     * @param String $content 字串
     * @return boolean
     */
public function check($content){
if(!isset($content) || $content==''){
return true;
        }
// protect white list
$content = $this->protect_white_list($content);
// check
if($this->_black_list){
foreach($this->_black_list as $val){
if(strstr($content, $val)!=''){
return false;
                }
            }
        }
return true;
    }
/** 保護白名單
     * @param String $content 字串
     * @return String
     */
private function protect_white_list($content){
if($this->_white_list){
foreach($this->_white_list as $key=>$val){
$content = str_replace($val, $this->_LTAG.$key.$this->_RTAG, $content);
            }
        }
return $content;
    }
/** 還原白名單
     * @param String $content
     * @return String
     */
private function resume_white_list($content){
if($this->_white_list){
$content = preg_replace_callback("/\[\[##(.*?)##\]\].*?/si", array($this, 'getval'), $content);
        }
return $content;
    }
/** 白名單 key還原為value
     * @param Array $matches 匹配white_list的key
     * @return String white_list val
     */
private function getval($matches){
return isset($this->_white_list[$matches[1]])? $this->_white_list[$matches[1]] : ''; // key->val
}
} // class end
header("content-type:text/html;charset=utf8");
$white = array('屌絲', '曹操','');
$black = array('屌', '操');
$content = "我操,曹操你是屌絲,我屌你啊，毛你好";
$obj = new StrFilter($white, $black);
echo $obj->check($content);